//
// Copyright 2019 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//

// MSRTTTest: Tests of EXT_multisampled_render_to_texture extension

#include <array>

#include "common/unsafe_buffers.h"
#include "test_utils/ANGLETest.h"
#include "test_utils/gl_raii.h"

#include "common/mathutil.h"

using namespace angle;

namespace
{

using MultisampledRenderToTextureTestParams = std::tuple<angle::PlatformParameters, bool>;

std::string PrintToStringParamName(
    const ::testing::TestParamInfo<MultisampledRenderToTextureTestParams> &info)
{
    std::stringstream ss;
    ss << std::get<0>(info.param);
    if (std::get<1>(info.param))
    {
        ss << "_RobustResourceInit";
    }
    return ss.str();
}

class MSRTTTest : public ANGLETest<MultisampledRenderToTextureTestParams>
{
  protected:
    MSRTTTest()
    {
        setWindowWidth(64);
        setWindowHeight(64);
        setConfigRedBits(8);
        setConfigGreenBits(8);
        setConfigBlueBits(8);
        setConfigAlphaBits(8);

        setRobustResourceInit(::testing::get<1>(GetParam()));
        forceNewDisplay();
    }

    void testSetUp() override
    {
        if (getClientMajorVersion() >= 3 && getClientMinorVersion() >= 1)
        {
            glGetIntegerv(GL_MAX_INTEGER_SAMPLES, &mMaxIntegerSamples);
        }
    }

    void testTearDown() override {}

    void assertErrorIfNotMSRTT2(GLenum error)
    {
        if (EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture2"))
        {
            ASSERT_GL_NO_ERROR();
        }
        else
        {
            ASSERT_GL_ERROR(error);
        }
    }

    void setupCopyTexProgram()
    {
        mCopyTextureProgram.makeRaster(essl1_shaders::vs::Texture2D(),
                                       essl1_shaders::fs::Texture2D());
        ASSERT_GL_TRUE(mCopyTextureProgram.valid());

        mCopyTextureUniformLocation =
            glGetUniformLocation(mCopyTextureProgram, essl1_shaders::Texture2DUniform());

        ASSERT_GL_NO_ERROR();
    }

    void setupUniformColorProgramMultiRenderTarget(const bool bufferEnabled[8], GLuint *programOut)
    {
        std::stringstream fs;

        fs << "#extension GL_EXT_draw_buffers : enable\n"
              "precision highp float;\n"
              "uniform mediump vec4 "
           << essl1_shaders::ColorUniform()
           << ";\n"
              "void main()\n"
              "{\n";

        for (unsigned int index = 0; index < 8; index++)
        {
            if (ANGLE_UNSAFE_TODO(bufferEnabled[index]))
            {
                fs << "    gl_FragData[" << index << "] = " << essl1_shaders::ColorUniform()
                   << ";\n";
            }
        }

        fs << "}\n";

        *programOut = CompileProgram(essl1_shaders::vs::Simple(), fs.str().c_str());
        ASSERT_NE(*programOut, 0u);
    }

    void verifyResults(GLuint texture,
                       const GLColor expected,
                       GLint fboSize,
                       GLint xs,
                       GLint ys,
                       GLint xe,
                       GLint ye)
    {
        glViewport(0, 0, fboSize, fboSize);

        glBindFramebuffer(GL_FRAMEBUFFER, 0);

        // Draw a quad with the target texture
        glUseProgram(mCopyTextureProgram);
        glBindTexture(GL_TEXTURE_2D, texture);
        glUniform1i(mCopyTextureUniformLocation, 0);

        glDisable(GL_DEPTH_TEST);
        glDisable(GL_STENCIL_TEST);
        glDisable(GL_BLEND);
        glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
        drawQuad(mCopyTextureProgram, essl1_shaders::PositionAttrib(), 0.5f);

        // Expect that the rendered quad has the same color as the source texture
        EXPECT_PIXEL_COLOR_NEAR(xs, ys, expected, 1.0);
        EXPECT_PIXEL_COLOR_NEAR(xs, ye - 1, expected, 1.0);
        EXPECT_PIXEL_COLOR_NEAR(xe - 1, ys, expected, 1.0);
        EXPECT_PIXEL_COLOR_NEAR(xe - 1, ye - 1, expected, 1.0);
        EXPECT_PIXEL_COLOR_NEAR((xs + xe) / 2, (ys + ye) / 2, expected, 1.0);
    }

    void clearAndDrawQuad(GLuint program, GLsizei viewportWidth, GLsizei viewportHeight)
    {
        glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);
        glViewport(0, 0, viewportWidth, viewportHeight);
        ASSERT_GL_NO_ERROR();

        drawQuad(program, essl1_shaders::PositionAttrib(), 0.0f);
        ASSERT_GL_NO_ERROR();
    }

    struct GLType
    {
        GLenum internalFormat;
        GLenum format;
        GLenum type;
    };

    void createAndAttachColorAttachment(bool useRenderbuffer,
                                        GLsizei size,
                                        GLenum renderbufferTarget,
                                        const GLType *glType,
                                        GLint samples,
                                        GLTexture *textureOut,
                                        GLRenderbuffer *renderbufferOut);
    void createAndAttachDepthStencilAttachment(bool useRenderbuffer,
                                               GLsizei size,
                                               GLTexture *textureOut,
                                               GLRenderbuffer *renderbufferOut);
    void colorAttachmentMultisampleDrawTestCommon(bool useRenderbuffer);
    void copyTexImageTestCommon(bool useRenderbuffer);
    void copyTexSubImageTestCommon(bool useRenderbuffer);
    void drawCopyThenBlendCommon(bool useRenderbuffer);
    void clearDrawCopyThenBlendSameProgramCommon(bool useRenderbuffer);
    void drawCopyDrawThenMaskedClearCommon(bool useRenderbuffer);
    void clearThenBlendCommon(bool useRenderbuffer);

    GLProgram mCopyTextureProgram;
    GLint mCopyTextureUniformLocation = -1;

    const GLint mTestSampleCount = 4;
    GLint mMaxIntegerSamples     = 0;
};

class MSRTTES3Test : public MSRTTTest
{
  protected:
    void readPixelsTestCommon(bool useRenderbuffer);
    void blitFramebufferTestCommon(bool useRenderbuffer);
    void drawCopyDrawAttachInvalidatedThenDrawCommon(bool useRenderbuffer);
    void drawCopyDrawAttachDepthStencilClearThenDrawCommon(bool useRenderbuffer);
    void depthStencilClearThenDrawCommon(bool useRenderbuffer);
    void colorAttachment1Common(bool useRenderbuffer);
    void colorAttachments0And3Common(bool useRenderbuffer);
    void blitFramebufferMixedColorAndDepthCommon(bool useRenderbuffer);
    void renderbufferUnresolveColorAndDepthStencilThenTwoColors(bool withDepth, bool withStencil);
};

class MSRTTES31Test : public MSRTTTest
{
  protected:
    void blitFramebufferAttachment1Common(bool useRenderbuffer);
    void drawCopyThenBlendAllAttachmentsMixed(bool useRenderbuffer);
};

// Checking against invalid parameters for RenderbufferStorageMultisampleEXT.
TEST_P(MSRTTTest, RenderbufferParameterCheck)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    // Linux Intel Vulkan returns 0 for GL_MAX_INTEGER_SAMPLES http://anglebug.com/42264519
    ANGLE_SKIP_TEST_IF(IsLinux() && IsIntel() && IsVulkan());

    GLRenderbuffer renderbuffer;
    glBindRenderbuffer(GL_RENDERBUFFER, renderbuffer);

    // Positive test case.  Formats required by the spec (GLES2.0 Table 4.5)
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_DEPTH_COMPONENT16, 64, 64);
    ASSERT_GL_NO_ERROR();
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_STENCIL_INDEX8, 64, 64);
    ASSERT_GL_NO_ERROR();
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_RGBA4, 64, 64);
    ASSERT_GL_NO_ERROR();
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_RGB5_A1, 64, 64);
    ASSERT_GL_NO_ERROR();
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_RGB565, 64, 64);
    ASSERT_GL_NO_ERROR();

    // Positive test case.  A few of the ES3 formats
    if (getClientMajorVersion() >= 3)
    {
        glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_DEPTH24_STENCIL8, 64, 64);
        ASSERT_GL_NO_ERROR();
        glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_RGBA8, 64, 64);
        ASSERT_GL_NO_ERROR();

        if (getClientMinorVersion() >= 1)
        {
            glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, mMaxIntegerSamples, GL_RGBA32I, 64,
                                                64);
            ASSERT_GL_NO_ERROR();
            glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, mMaxIntegerSamples, GL_RGBA32UI,
                                                64, 64);
            ASSERT_GL_NO_ERROR();
        }
    }

    GLint samples;
    glGetIntegerv(GL_MAX_SAMPLES_EXT, &samples);
    ASSERT_GL_NO_ERROR();
    EXPECT_GE(samples, 1);

    // Samples too large
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, samples + 1, GL_DEPTH_COMPONENT16, 64, 64);
    ASSERT_GL_ERROR(GL_INVALID_VALUE);

    // Renderbuffer size too large
    GLint maxSize;
    glGetIntegerv(GL_MAX_RENDERBUFFER_SIZE, &maxSize);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 2, GL_RGBA4, maxSize + 1, maxSize);
    ASSERT_GL_ERROR(GL_INVALID_VALUE);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 2, GL_DEPTH_COMPONENT16, maxSize,
                                        maxSize + 1);
    ASSERT_GL_ERROR(GL_INVALID_VALUE);

    // Retrieving samples
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_DEPTH_COMPONENT16, 64, 64);
    GLint param = 0;
    glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_SAMPLES_EXT, &param);
    // GE because samples may vary base on implementation. Spec says "the resulting value for
    // RENDERBUFFER_SAMPLES_EXT is guaranteed to be greater than or equal to samples and no more
    // than the next larger sample count supported by the implementation"
    EXPECT_GE(param, 4);
}

// Checking against invalid parameters for FramebufferTexture2DMultisampleEXT.
TEST_P(MSRTTTest, Texture2DParameterCheck)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    bool isES3 = getClientMajorVersion() >= 3;

    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 64, 64, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    ASSERT_GL_NO_ERROR();

    GLTexture depthTexture;
    if (isES3)
    {
        glBindTexture(GL_TEXTURE_2D, depthTexture);
        glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH24_STENCIL8, 64, 64, 0, GL_DEPTH_STENCIL,
                     GL_UNSIGNED_INT_24_8_OES, nullptr);
    }

    GLFramebuffer fbo;
    glBindFramebuffer(GL_FRAMEBUFFER, fbo);
    // Positive test case
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, 4);
    ASSERT_GL_NO_ERROR();
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    if (EnsureGLExtensionEnabled("GL_EXT_draw_buffers") || isES3)
    {
        // Attachment not COLOR_ATTACHMENT0.  Allowed only in EXT_multisampled_render_to_texture2
        glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, GL_TEXTURE_2D,
                                             texture, 0, 4);
        assertErrorIfNotMSRTT2(GL_INVALID_ENUM);
    }

    // Depth/stencil attachment.  Allowed only in EXT_multisampled_render_to_texture2
    if (isES3)
    {
        glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D,
                                             depthTexture, 0, 4);
        assertErrorIfNotMSRTT2(GL_INVALID_ENUM);

        glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_TEXTURE_2D,
                                             depthTexture, 0, 4);
        assertErrorIfNotMSRTT2(GL_INVALID_ENUM);

        glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT,
                                             GL_TEXTURE_2D, depthTexture, 0, 4);
        assertErrorIfNotMSRTT2(GL_INVALID_ENUM);

        glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, GL_TEXTURE_2D,
                                             depthTexture, 0, 4);
        assertErrorIfNotMSRTT2(GL_INVALID_ENUM);
    }

    // Attachment not 2D texture
    GLTexture cube;
    glBindTexture(GL_TEXTURE_CUBE_MAP, cube);
    for (GLenum face = 0; face < 6; face++)
    {
        glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, 0, GL_RGBA, 64, 64, 0, GL_RGBA,
                     GL_UNSIGNED_BYTE, nullptr);
        ASSERT_GL_NO_ERROR();
    }
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, cube,
                                         0, 4);
    ASSERT_GL_ERROR(GL_INVALID_OPERATION);

    // Target not framebuffer
    glFramebufferTexture2DMultisampleEXT(GL_RENDERBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, 4);
    ASSERT_GL_ERROR(GL_INVALID_ENUM);

    GLint samples;
    glGetIntegerv(GL_MAX_SAMPLES_EXT, &samples);
    ASSERT_GL_NO_ERROR();
    EXPECT_GE(samples, 1);

    // Samples negative
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, -1);
    ASSERT_GL_ERROR(GL_INVALID_VALUE);

    // Samples too large
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, samples + 1);
    ASSERT_GL_ERROR(GL_INVALID_VALUE);

    // Retrieving samples
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, 4);
    GLint param = 0;
    glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                          GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_SAMPLES_EXT, &param);
    // GE because samples may vary base on implementation. Spec says "the resulting value for
    // TEXTURE_SAMPLES_EXT is guaranteed to be greater than or equal to samples and no more than the
    // next larger sample count supported by the implementation"
    EXPECT_GE(param, 4);
}

// Checking against invalid parameters for FramebufferTexture2DMultisampleEXT (cubemap).
TEST_P(MSRTTTest, TextureCubeMapParameterCheck)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    bool isES3 = getClientMajorVersion() >= 3;

    GLTexture texture;
    glBindTexture(GL_TEXTURE_CUBE_MAP, texture);
    for (GLenum face = 0; face < 6; face++)
    {
        glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, 0, GL_RGBA, 64, 64, 0, GL_RGBA,
                     GL_UNSIGNED_BYTE, nullptr);
        ASSERT_GL_NO_ERROR();
    }

    GLint samples;
    glGetIntegerv(GL_MAX_SAMPLES_EXT, &samples);
    ASSERT_GL_NO_ERROR();
    EXPECT_GE(samples, 1);

    GLFramebuffer FBO;
    glBindFramebuffer(GL_FRAMEBUFFER, FBO);
    for (GLenum face = 0; face < 6; face++)
    {
        // Positive test case
        glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                             GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, texture, 0, 4);
        ASSERT_GL_NO_ERROR();
        EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

        if (EnsureGLExtensionEnabled("GL_EXT_draw_buffers") || isES3)
        {
            // Attachment not COLOR_ATTACHMENT0.  Allowed only in
            // EXT_multisampled_render_to_texture2
            glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1,
                                                 GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, texture, 0,
                                                 4);
            assertErrorIfNotMSRTT2(GL_INVALID_ENUM);
        }

        // Target not framebuffer
        glFramebufferTexture2DMultisampleEXT(GL_RENDERBUFFER, GL_COLOR_ATTACHMENT0,
                                             GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, texture, 0, 4);
        ASSERT_GL_ERROR(GL_INVALID_ENUM);

        // Samples too large
        glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                             GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, texture, 0,
                                             samples + 1);
        ASSERT_GL_ERROR(GL_INVALID_VALUE);

        // Retrieving samples
        glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                             GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, texture, 0, 4);
        GLint param = 0;
        glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                              GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_SAMPLES_EXT,
                                              &param);
        // GE because samples may vary base on implementation. Spec says "the resulting value for
        // TEXTURE_SAMPLES_EXT is guaranteed to be greater than or equal to samples and no more than
        // the next larger sample count supported by the implementation"
        EXPECT_GE(param, 4);
    }

    // Attachment not cubemap texture
    GLTexture notcube;
    glBindTexture(GL_TEXTURE_2D, notcube);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 64, 64, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                         GL_TEXTURE_CUBE_MAP_POSITIVE_X, notcube, 0, 4);
    ASSERT_GL_ERROR(GL_INVALID_OPERATION);
}

// Checking for framebuffer completeness using extension methods.
TEST_P(MSRTTTest, FramebufferCompleteness)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    // Checking that Renderbuffer and texture2d having different number of samples results
    // in a FRAMEBUFFER_INCOMPLETE_MULTISAMPLE
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 64, 64, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    ASSERT_GL_NO_ERROR();

    // Texture attachment for color attachment 0.  Framebuffer should be complete.
    GLFramebuffer FBO;
    glBindFramebuffer(GL_FRAMEBUFFER, FBO);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, 4);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    GLsizei maxSamples = 0;
    glGetIntegerv(GL_MAX_SAMPLES, &maxSamples);

    // Depth/stencil renderbuffer, potentially with a different sample count.
    GLRenderbuffer dsRenderbuffer;
    glBindRenderbuffer(GL_RENDERBUFFER, dsRenderbuffer);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, maxSamples, GL_DEPTH_COMPONENT16, 64, 64);
    ASSERT_GL_NO_ERROR();
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, dsRenderbuffer);

    if (maxSamples > 4)
    {
        EXPECT_GLENUM_EQ(GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE,
                         glCheckFramebufferStatus(GL_FRAMEBUFFER));
    }
    else
    {
        EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);
    }

    // Color renderbuffer for color attachment 0.
    GLRenderbuffer colorRenderbuffer;
    glBindRenderbuffer(GL_RENDERBUFFER, colorRenderbuffer);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, maxSamples, GL_RGBA4, 64, 64);
    ASSERT_GL_NO_ERROR();
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER,
                              colorRenderbuffer);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    if (getClientMajorVersion() >= 3 &&
        EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture2"))
    {
        // Texture attachment for color attachment 1.
        GLTexture texture2;
        glBindTexture(GL_TEXTURE_2D, texture2);
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 64, 64, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
        ASSERT_GL_NO_ERROR();

        // Attach with a potentially different number of samples.
        glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, GL_TEXTURE_2D,
                                             texture, 0, 4);

        if (maxSamples > 4)
        {
            EXPECT_GLENUM_EQ(GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE,
                             glCheckFramebufferStatus(GL_FRAMEBUFFER));
        }
        else
        {
            EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);
        }

        // Attach with same number of samples.
        glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, GL_TEXTURE_2D,
                                             texture, 0, maxSamples);
        EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);
    }
}

// Checking for framebuffer completeness using extension methods.
TEST_P(MSRTTTest, FramebufferCompletenessSmallSampleCount)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    // A sample count of '2' can be rounded up to '4' on some systems (e.g., ARM+Android).
    GLsizei samples = 2;

    // Checking that Renderbuffer and texture2d having different number of samples results
    // in a FRAMEBUFFER_INCOMPLETE_MULTISAMPLE
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 64, 64, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    ASSERT_GL_NO_ERROR();

    // Texture attachment for color attachment 0.  Framebuffer should be complete.
    GLFramebuffer FBO;
    glBindFramebuffer(GL_FRAMEBUFFER, FBO);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, samples);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Depth/stencil renderbuffer, potentially with a different sample count.
    GLRenderbuffer dsRenderbuffer;
    glBindRenderbuffer(GL_RENDERBUFFER, dsRenderbuffer);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, samples, GL_DEPTH_COMPONENT16, 64, 64);
    ASSERT_GL_NO_ERROR();
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, dsRenderbuffer);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Color renderbuffer for color attachment 0.
    GLRenderbuffer colorRenderbuffer;
    glBindRenderbuffer(GL_RENDERBUFFER, colorRenderbuffer);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, samples, GL_RGBA4, 64, 64);
    ASSERT_GL_NO_ERROR();
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER,
                              colorRenderbuffer);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);
}

// Test mixing unsized and sized formats with multisampling. Regression test for
// http://crbug.com/1238327
TEST_P(MSRTTTest, UnsizedTextureFormatSampleMissmatch)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_texture_rg"));

    GLsizei samples = 0;
    glGetIntegerv(GL_MAX_SAMPLES, &samples);

    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, 64, 64, 0, GL_RED, GL_UNSIGNED_BYTE, nullptr);
    ASSERT_GL_NO_ERROR();

    // Texture attachment for color attachment 0.  Framebuffer should be complete.
    GLFramebuffer FBO;
    glBindFramebuffer(GL_FRAMEBUFFER, FBO);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, samples);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Depth/stencil renderbuffer, potentially with a different sample count.
    GLRenderbuffer dsRenderbuffer;
    glBindRenderbuffer(GL_RENDERBUFFER, dsRenderbuffer);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, samples, GL_STENCIL_INDEX8, 64, 64);
    ASSERT_GL_NO_ERROR();
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_RENDERBUFFER,
                              dsRenderbuffer);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);
}

void MSRTTTest::createAndAttachColorAttachment(bool useRenderbuffer,
                                               GLsizei size,
                                               GLenum renderbufferTarget,
                                               const GLType *glType,
                                               GLint samples,
                                               GLTexture *textureOut,
                                               GLRenderbuffer *renderbufferOut)
{
    GLenum internalFormat = glType ? glType->internalFormat : GL_RGBA;
    GLenum format         = glType ? glType->format : GL_RGBA;
    GLenum type           = glType ? glType->type : GL_UNSIGNED_BYTE;

    if (useRenderbuffer)
    {
        if (internalFormat == GL_RGBA)
        {
            internalFormat = GL_RGBA8;
        }
        glBindRenderbuffer(GL_RENDERBUFFER, *renderbufferOut);
        glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, samples, internalFormat, size, size);
        glFramebufferRenderbuffer(GL_FRAMEBUFFER, renderbufferTarget, GL_RENDERBUFFER,
                                  *renderbufferOut);
    }
    else
    {
        glBindTexture(GL_TEXTURE_2D, *textureOut);
        glTexImage2D(GL_TEXTURE_2D, 0, internalFormat, size, size, 0, format, type, nullptr);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
        glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, renderbufferTarget, GL_TEXTURE_2D,
                                             *textureOut, 0, samples);
    }
    ASSERT_GL_NO_ERROR();
}

void MSRTTTest::createAndAttachDepthStencilAttachment(bool useRenderbuffer,
                                                      GLsizei size,
                                                      GLTexture *textureOut,
                                                      GLRenderbuffer *renderbufferOut)
{
    if (useRenderbuffer)
    {
        glBindRenderbuffer(GL_RENDERBUFFER, *renderbufferOut);
        glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, mTestSampleCount, GL_DEPTH24_STENCIL8,
                                            size, size);
        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER,
                                  *renderbufferOut);
    }
    else
    {
        glBindTexture(GL_TEXTURE_2D, *textureOut);
        glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH24_STENCIL8, size, size, 0, GL_DEPTH_STENCIL,
                     GL_UNSIGNED_INT_24_8_OES, nullptr);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
        glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT,
                                             GL_TEXTURE_2D, *textureOut, 0, mTestSampleCount);
    }
    ASSERT_GL_NO_ERROR();
}

void MSRTTTest::colorAttachmentMultisampleDrawTestCommon(bool useRenderbuffer)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    GLFramebuffer FBO;
    glBindFramebuffer(GL_FRAMEBUFFER, FBO);

    // Set up color attachment and bind to FBO
    constexpr GLsizei kSize = 6;
    GLTexture texture;
    GLRenderbuffer renderbuffer;
    createAndAttachColorAttachment(useRenderbuffer, kSize, GL_COLOR_ATTACHMENT0, nullptr,
                                   mTestSampleCount, &texture, &renderbuffer);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Set viewport and clear to blue
    glViewport(0, 0, kSize, kSize);
    glClearColor(0.0, 0.0, 1.0, 1.0);
    glClear(GL_COLOR_BUFFER_BIT);

    // Set up Green square program
    ANGLE_GL_PROGRAM(program, essl1_shaders::vs::Simple(), essl1_shaders::fs::Green());
    glUseProgram(program);
    GLint positionLocation = glGetAttribLocation(program, essl1_shaders::PositionAttrib());
    ASSERT_NE(-1, positionLocation);

    setupQuadVertexBuffer(0.5f, 0.5f);
    glVertexAttribPointer(positionLocation, 3, GL_FLOAT, GL_FALSE, 0, 0);
    glEnableVertexAttribArray(positionLocation);

    // Draw green square
    glDrawArrays(GL_TRIANGLES, 0, 6);
    ASSERT_GL_NO_ERROR();

    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(kSize / 2, kSize / 2, GLColor::green);

    // Set up Red square program
    ANGLE_GL_PROGRAM(program2, essl1_shaders::vs::Simple(), essl1_shaders::fs::Red());
    glUseProgram(program2);
    GLint positionLocation2 = glGetAttribLocation(program2, essl1_shaders::PositionAttrib());
    ASSERT_NE(-1, positionLocation2);

    setupQuadVertexBuffer(0.5f, 0.75f);
    glVertexAttribPointer(positionLocation2, 3, GL_FLOAT, GL_FALSE, 0, 0);

    // Draw red square
    glDrawArrays(GL_TRIANGLES, 0, 6);
    ASSERT_GL_NO_ERROR();

    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(kSize / 2, kSize / 2, GLColor::red);

    glDisableVertexAttribArray(0);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
}

// Draw test with color attachment only.
TEST_P(MSRTTTest, 2DColorAttachmentMultisampleDrawTest)
{
    colorAttachmentMultisampleDrawTestCommon(false);
}

// Draw test with renderbuffer color attachment only
TEST_P(MSRTTTest, RenderbufferColorAttachmentMultisampleDrawTest)
{
    colorAttachmentMultisampleDrawTestCommon(true);
}

// Test draw with a scissored region.
TEST_P(MSRTTTest, ScissoredDrawTest)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    GLFramebuffer FBO;
    glBindFramebuffer(GL_FRAMEBUFFER, FBO);

    // Set up color attachment and bind to FBO
    constexpr GLsizei kSize = 1024;
    GLTexture texture;
    GLRenderbuffer renderbuffer;
    createAndAttachColorAttachment(false, kSize, GL_COLOR_ATTACHMENT0, nullptr, mTestSampleCount,
                                   &texture, &renderbuffer);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Set viewport and clear to black
    glViewport(0, 0, kSize, kSize);
    glClearColor(0.0, 0.0, 0.0, 1.0);
    glClear(GL_COLOR_BUFFER_BIT);

    // Set up Green square program
    ANGLE_GL_PROGRAM(drawGreen, essl1_shaders::vs::Simple(), essl1_shaders::fs::Green());
    glUseProgram(drawGreen);

    // Draw green square
    drawQuad(drawGreen, essl1_shaders::PositionAttrib(), 0.0f);
    ASSERT_GL_NO_ERROR();

    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, 0, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(0, kSize - 1, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, kSize - 1, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(kSize / 2, kSize / 2, GLColor::green);

    // Set up Red square program
    ANGLE_GL_PROGRAM(drawRed, essl1_shaders::vs::Simple(), essl1_shaders::fs::Red());
    glUseProgram(drawRed);

    // Draw a scissored red square

    constexpr GLint kScissorStartX = 1;
    constexpr GLint kScissorStartY = 103;
    constexpr GLint kScissorEndX   = 285;
    constexpr GLint kScissorEndY   = 402;

    glEnable(GL_SCISSOR_TEST);
    glScissor(kScissorStartX, kScissorStartY, kScissorEndX - kScissorStartX + 1,
              kScissorEndY - kScissorStartY + 1);
    drawQuad(drawRed, essl1_shaders::PositionAttrib(), 0.0f);
    ASSERT_GL_NO_ERROR();

    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, 0, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(0, kSize - 1, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, kSize - 1, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(kSize / 2, kSize / 2, GLColor::green);

    EXPECT_PIXEL_COLOR_EQ(kScissorStartX, kScissorStartY, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kScissorEndX, kScissorStartY, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kScissorStartX, kScissorEndY, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kScissorEndX, kScissorEndY, GLColor::red);

    EXPECT_PIXEL_COLOR_EQ(kScissorStartX - 1, kScissorStartY, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(kScissorStartX, kScissorStartY - 1, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(kScissorEndX + 1, kScissorStartY, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(kScissorEndX, kScissorStartY - 1, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(kScissorStartX - 1, kScissorEndY, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(kScissorStartX, kScissorEndY + 1, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(kScissorEndX + 1, kScissorEndY, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(kScissorEndX, kScissorEndY + 1, GLColor::green);
}

// Test transform feedback with state change.  In the Vulkan backend, this results in an implicit
// break of the render pass, and must work correctly with respect to the subpass index that's used.
TEST_P(MSRTTES3Test, TransformFeedbackTest)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    GLFramebuffer FBO;
    glBindFramebuffer(GL_FRAMEBUFFER, FBO);

    // Set up color attachment and bind to FBO
    constexpr GLsizei kSize = 1024;
    GLTexture texture;
    GLRenderbuffer renderbuffer;
    createAndAttachColorAttachment(false, kSize, GL_COLOR_ATTACHMENT0, nullptr, mTestSampleCount,
                                   &texture, &renderbuffer);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Set up transform feedback.
    GLTransformFeedback xfb;
    glBindTransformFeedback(GL_TRANSFORM_FEEDBACK, xfb);

    constexpr size_t kXfbBufferSize = 1024;  // arbitrary number
    GLBuffer xfbBuffer;
    glBindBuffer(GL_TRANSFORM_FEEDBACK_BUFFER, xfbBuffer);
    glBufferData(GL_TRANSFORM_FEEDBACK_BUFFER, kXfbBufferSize, nullptr, GL_STATIC_DRAW);
    glBindBufferBase(GL_TRANSFORM_FEEDBACK_BUFFER, 0, xfbBuffer);

    // Set up program with transform feedback
    std::vector<std::string> tfVaryings = {"gl_Position"};
    ANGLE_GL_PROGRAM_TRANSFORM_FEEDBACK(drawColor, essl1_shaders::vs::Simple(),
                                        essl1_shaders::fs::UniformColor(), tfVaryings,
                                        GL_INTERLEAVED_ATTRIBS);
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);

    // Start transform feedback
    glBeginTransformFeedback(GL_TRIANGLES);

    // Set viewport and clear to black
    glViewport(0, 0, kSize, kSize);
    glClearColor(0.0, 0.0, 0.0, 1.0);
    glClear(GL_COLOR_BUFFER_BIT);

    // Draw green.  There's no unresolve operation as the framebuffer has just been cleared.
    glUniform4f(colorUniformLocation, 0.0f, 1.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.0f);
    ASSERT_GL_NO_ERROR();

    // Incur a state change while transform feedback is active.  This will result in a pipeline
    // rebind in the Vulkan backend, which should necessarily break the render pass when
    // VK_EXT_transform_feedback is used.
    glEnable(GL_BLEND);
    glBlendFunc(GL_ONE, GL_ONE);

    // Draw red.  The implicit render pass break means that there's an unresolve operation.
    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.0f);

    // End transform feedback
    glEndTransformFeedback();

    // Expect yellow.
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::yellow);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, 0, GLColor::yellow);
    EXPECT_PIXEL_COLOR_EQ(0, kSize - 1, GLColor::yellow);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, kSize - 1, GLColor::yellow);
    EXPECT_PIXEL_COLOR_EQ(kSize / 2, kSize / 2, GLColor::yellow);
}

// Draw test using both color and depth attachments.
TEST_P(MSRTTTest, 2DColorDepthMultisampleDrawTest)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    constexpr GLsizei kSize = 6;
    // create complete framebuffer with depth buffer
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    ASSERT_GL_NO_ERROR();

    GLFramebuffer FBO;
    glBindFramebuffer(GL_FRAMEBUFFER, FBO);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, 4);

    GLRenderbuffer renderbuffer;
    glBindRenderbuffer(GL_RENDERBUFFER, renderbuffer);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_DEPTH_COMPONENT16, kSize, kSize);
    ASSERT_GL_NO_ERROR();
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, renderbuffer);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Set viewport and clear framebuffer
    glViewport(0, 0, kSize, kSize);
    glClearColor(0.0, 0.0, 0.0, 1.0);
    glClearDepthf(0.5f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    // Draw first green square
    ANGLE_GL_PROGRAM(program, essl1_shaders::vs::Simple(), essl1_shaders::fs::Green());
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_GREATER);
    glUseProgram(program);
    GLint positionLocation = glGetAttribLocation(program, essl1_shaders::PositionAttrib());
    ASSERT_NE(-1, positionLocation);

    setupQuadVertexBuffer(0.8f, 0.5f);
    glVertexAttribPointer(positionLocation, 3, GL_FLOAT, GL_FALSE, 0, 0);
    glEnableVertexAttribArray(positionLocation);

    // Tests that TRIANGLES works.
    glDrawArrays(GL_TRIANGLES, 0, 6);
    ASSERT_GL_NO_ERROR();

    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::black);
    EXPECT_PIXEL_COLOR_EQ(kSize / 2, kSize / 2, GLColor::green);

    // Draw red square behind green square
    ANGLE_GL_PROGRAM(program2, essl1_shaders::vs::Simple(), essl1_shaders::fs::Red());
    glUseProgram(program2);
    GLint positionLocation2 = glGetAttribLocation(program2, essl1_shaders::PositionAttrib());
    ASSERT_NE(-1, positionLocation2);

    setupQuadVertexBuffer(0.7f, 1.0f);
    glVertexAttribPointer(positionLocation2, 3, GL_FLOAT, GL_FALSE, 0, 0);

    glDrawArrays(GL_TRIANGLES, 0, 6);
    ASSERT_GL_NO_ERROR();
    glDisable(GL_DEPTH_TEST);

    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kSize / 2, kSize / 2, GLColor::green);

    glDisableVertexAttribArray(0);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
}

// Draw test using color attachment with multiple levels.
TEST_P(MSRTTTest, MultipleLevelsMultisampleDraw2DColor)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    constexpr GLsizei kSize        = 256;
    const GLuint desiredLevelCount = gl::log2(kSize) + 1;
    const std::vector<GLColor> greenColor(kSize * kSize, GLColor::green);

    // Create texture to be used as color attachment
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);

    // Initialize all levels
    for (GLuint level = 0; level < desiredLevelCount; level++)
    {
        GLsizei levelSize = kSize >> level;
        glTexImage2D(GL_TEXTURE_2D, level, GL_RGBA, levelSize, levelSize, 0, GL_RGBA,
                     GL_UNSIGNED_BYTE, greenColor.data());
    }

    GLFramebuffer FBO;
    GLFramebuffer readFbo;

    // Multisample draw and verify with each level
    for (GLuint currentLevel = 0; currentLevel < desiredLevelCount; currentLevel++)
    {
        GLsizei currentLevelSize = kSize >> currentLevel;

        // Attach a texture level as color attachment
        glBindFramebuffer(GL_FRAMEBUFFER, FBO);
        glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                             texture, currentLevel, 4);
        EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

        // Draw blue color
        glViewport(0, 0, currentLevelSize, currentLevelSize);
        ANGLE_GL_PROGRAM(program, essl1_shaders::vs::Simple(), essl1_shaders::fs::Blue());
        glUseProgram(program);
        drawQuad(program, essl1_shaders::PositionAttrib(), 0.5f);
        ASSERT_GL_NO_ERROR();

        // Verify blue color
        glBindFramebuffer(GL_FRAMEBUFFER, readFbo);
        glBindTexture(GL_TEXTURE_2D, texture);
        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture,
                               currentLevel);
        EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

        EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::blue);
        EXPECT_PIXEL_COLOR_EQ(currentLevelSize / 2, currentLevelSize / 2, GLColor::blue);
    }
}

// Draw test using color attachment with multiple levels and multiple render targets.
TEST_P(MSRTTES3Test, MultipleLevelsMultisampleMRTDraw2DColor)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_draw_buffers"));

    constexpr GLsizei kSize        = 256;
    const GLuint desiredLevelCount = gl::log2(kSize) + 1;
    const std::vector<GLColor> greenColor(kSize * kSize, GLColor::green);

    // Create texture to be used as color attachment
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);

    // Initialize all levels
    for (GLuint level = 0; level < desiredLevelCount; level++)
    {
        GLsizei levelSize = kSize >> level;
        glTexImage2D(GL_TEXTURE_2D, level, GL_RGBA, levelSize, levelSize, 0, GL_RGBA,
                     GL_UNSIGNED_BYTE, greenColor.data());
    }

    // Multisample MRT draw and verify
    const std::string frag = R"(#extension GL_EXT_draw_buffers : enable
        precision highp float;
        uniform mediump vec4 u_color;
        void main()
        {
            gl_FragData[0] = u_color;
            gl_FragData[1] = u_color;
        })";
    ANGLE_GL_PROGRAM(mrtProgram, essl1_shaders::vs::Simple(), frag.c_str());
    glUseProgram(mrtProgram);
    GLint colorUniformLocation = glGetUniformLocation(mrtProgram, "u_color");
    ASSERT_NE(colorUniformLocation, -1);
    glUniform4f(colorUniformLocation, 1.0f, 1.0f, 0.0f, 1.0f);

    // Attach texture level 0 and 1 as color attachment
    GLFramebuffer FBO;
    glBindFramebuffer(GL_FRAMEBUFFER, FBO);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, 4);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, GL_TEXTURE_2D,
                                         texture, 1, 4);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Draw yellow color to both attachments
    glViewport(0, 0, kSize, kSize);
    constexpr GLenum kDrawBuffers[] = {GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1};
    glDrawBuffers(2, kDrawBuffers);
    ASSERT_GL_NO_ERROR();
    drawQuad(mrtProgram, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Verify yellow color in common render area of both attachments
    GLFramebuffer readFbo;
    glBindFramebuffer(GL_FRAMEBUFFER, readFbo);
    glBindTexture(GL_TEXTURE_2D, texture);

    // Verify level 0
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture, 0);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);
    EXPECT_PIXEL_COLOR_EQ((kSize >> 1) - 1, (kSize >> 1) - 1, GLColor::yellow);

    // Verify level 1
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture, 1);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);
    EXPECT_PIXEL_COLOR_EQ((kSize >> 1) - 1, (kSize >> 1) - 1, GLColor::yellow);
}

void MSRTTES3Test::readPixelsTestCommon(bool useRenderbuffer)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    GLFramebuffer FBO;
    glBindFramebuffer(GL_FRAMEBUFFER, FBO);

    constexpr GLsizei kSize = 6;
    GLTexture texture;
    GLRenderbuffer renderbuffer;
    createAndAttachColorAttachment(useRenderbuffer, kSize, GL_COLOR_ATTACHMENT0, nullptr,
                                   mTestSampleCount, &texture, &renderbuffer);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Set viewport and clear to red
    glViewport(0, 0, kSize, kSize);
    glClearColor(1.0f, 0.0f, 0.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);
    ASSERT_GL_NO_ERROR();

    // Bind Pack Pixel Buffer and read to it
    GLBuffer PBO;
    glBindBuffer(GL_PIXEL_PACK_BUFFER, PBO);
    glBufferData(GL_PIXEL_PACK_BUFFER, 4 * kSize * kSize, nullptr, GL_STATIC_DRAW);
    glReadPixels(0, 0, kSize, kSize, GL_RGBA, GL_UNSIGNED_BYTE, 0);
    ASSERT_GL_NO_ERROR();

    // Retrieving pixel color
    void *mappedPtr    = glMapBufferRange(GL_PIXEL_PACK_BUFFER, 0, 32, GL_MAP_READ_BIT);
    GLColor *dataColor = static_cast<GLColor *>(mappedPtr);
    EXPECT_GL_NO_ERROR();

    EXPECT_EQ(GLColor::red, dataColor[0]);

    glUnmapBuffer(GL_PIXEL_PACK_BUFFER);
    EXPECT_GL_NO_ERROR();
}

// Read pixels with pack buffer. ES3+.
TEST_P(MSRTTES3Test, ReadPixelsTest)
{
    readPixelsTestCommon(false);
}

// Read pixels with pack buffer from renderbuffer. ES3+.
TEST_P(MSRTTES3Test, RenderbufferReadPixelsTest)
{
    readPixelsTestCommon(true);
}

void MSRTTTest::copyTexImageTestCommon(bool useRenderbuffer)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    constexpr GLsizei kSize = 16;

    setupCopyTexProgram();

    GLFramebuffer FBO;
    glBindFramebuffer(GL_FRAMEBUFFER, FBO);

    GLTexture texture;
    GLRenderbuffer renderbuffer;
    createAndAttachColorAttachment(useRenderbuffer, kSize, GL_COLOR_ATTACHMENT0, nullptr,
                                   mTestSampleCount, &texture, &renderbuffer);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Set color for framebuffer
    glClearColor(0.25f, 1.0f, 0.75f, 0.5f);
    glClear(GL_COLOR_BUFFER_BIT);
    ASSERT_GL_NO_ERROR();

    GLTexture copyToTex;
    glBindTexture(GL_TEXTURE_2D, copyToTex);

    // Disable mipmapping
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 0, 0, kSize, kSize, 0);
    ASSERT_GL_NO_ERROR();

    verifyResults(copyToTex, {64, 255, 191, 255}, kSize, 0, 0, kSize, kSize);
}

// CopyTexImage from a multisampled texture functionality test.
TEST_P(MSRTTTest, CopyTexImageTest)
{
    copyTexImageTestCommon(false);
}

// CopyTexImage from a multisampled texture functionality test using renderbuffer.
TEST_P(MSRTTTest, RenderbufferCopyTexImageTest)
{
    copyTexImageTestCommon(true);
}

void MSRTTTest::copyTexSubImageTestCommon(bool useRenderbuffer)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    constexpr GLsizei kSize = 16;

    setupCopyTexProgram();

    GLFramebuffer copyFBO0;
    glBindFramebuffer(GL_FRAMEBUFFER, copyFBO0);

    // Create color attachment for copyFBO0
    GLTexture texture;
    GLRenderbuffer renderbuffer;
    createAndAttachColorAttachment(useRenderbuffer, kSize, GL_COLOR_ATTACHMENT0, nullptr,
                                   mTestSampleCount, &texture, &renderbuffer);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    GLFramebuffer copyFBO1;
    glBindFramebuffer(GL_FRAMEBUFFER, copyFBO1);

    // Create color attachment for copyFBO1
    GLTexture texture1;
    GLRenderbuffer renderbuffer1;
    createAndAttachColorAttachment(useRenderbuffer, kSize, GL_COLOR_ATTACHMENT0, nullptr,
                                   mTestSampleCount, &texture1, &renderbuffer1);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Set color for copyFBO0
    glBindFramebuffer(GL_FRAMEBUFFER, copyFBO0);
    glClearColor(0.25f, 1.0f, 0.75f, 0.5f);
    glClear(GL_COLOR_BUFFER_BIT);
    ASSERT_GL_NO_ERROR();

    // Set color for copyFBO1
    glBindFramebuffer(GL_FRAMEBUFFER, copyFBO1);
    glClearColor(1.0f, 0.75f, 0.5f, 0.25f);
    glClear(GL_COLOR_BUFFER_BIT);
    ASSERT_GL_NO_ERROR();

    GLTexture copyToTex;
    glBindTexture(GL_TEXTURE_2D, copyToTex);

    // Disable mipmapping
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

    // copyFBO0 -> copyToTex
    // copyToTex should hold what was originally in copyFBO0 : (.25, 1, .75, .5)
    glBindFramebuffer(GL_FRAMEBUFFER, copyFBO0);
    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 0, 0, kSize, kSize, 0);
    ASSERT_GL_NO_ERROR();

    const GLColor expected0(64, 255, 191, 255);
    verifyResults(copyToTex, expected0, kSize, 0, 0, kSize, kSize);

    // copyFBO[1] - copySubImage -> copyToTex
    // copyToTex should have subportion what was in copyFBO[1] : (1, .75, .5, .25)
    // The rest should still be untouched: (.25, 1, .75, .5)
    GLint half = kSize / 2;
    glBindFramebuffer(GL_FRAMEBUFFER, copyFBO1);
    glCopyTexSubImage2D(GL_TEXTURE_2D, 0, half, half, half, half, half, half);
    ASSERT_GL_NO_ERROR();

    const GLColor expected1(255, 191, 127, 255);
    verifyResults(copyToTex, expected1, kSize, half, half, kSize, kSize);

    // Verify rest is untouched
    verifyResults(copyToTex, expected0, kSize, 0, 0, half, half);
    verifyResults(copyToTex, expected0, kSize, 0, half, half, kSize);
    verifyResults(copyToTex, expected0, kSize, half, 0, kSize, half);
}

// CopyTexSubImage from a multisampled texture functionality test.
TEST_P(MSRTTTest, CopyTexSubImageTest)
{
    copyTexSubImageTestCommon(false);
}

// CopyTexSubImage from a multisampled texture functionality test with renderbuffers
TEST_P(MSRTTTest, RenderbufferCopyTexSubImageTest)
{
    copyTexSubImageTestCommon(true);
}

void MSRTTES3Test::blitFramebufferTestCommon(bool useRenderbuffer)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    constexpr GLsizei kSize = 16;

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    // Create multisampled framebuffer to use as source.
    GLRenderbuffer depthMS;
    glBindRenderbuffer(GL_RENDERBUFFER, depthMS);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_DEPTH_COMPONENT24, kSize, kSize);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthMS);
    ASSERT_GL_NO_ERROR();

    GLTexture textureMS;
    GLRenderbuffer renderbufferMS;
    createAndAttachColorAttachment(useRenderbuffer, kSize, GL_COLOR_ATTACHMENT0, nullptr,
                                   mTestSampleCount, &textureMS, &renderbufferMS);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Clear depth to 0.5 and color to green.
    glClearDepthf(0.5f);
    glClearColor(0.0f, 1.0f, 0.0f, 1.0f);
    glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
    glFlush();
    ASSERT_GL_NO_ERROR();

    // Draw red into the multisampled color buffer.
    ANGLE_GL_PROGRAM(drawRed, essl1_shaders::vs::Simple(), essl1_shaders::fs::Red());
    ANGLE_GL_PROGRAM(drawBlue, essl1_shaders::vs::Simple(), essl1_shaders::fs::Blue());
    glEnable(GL_DEPTH_TEST);
    drawQuad(drawRed, essl1_shaders::PositionAttrib(), -0.05f);
    drawQuad(drawBlue, essl1_shaders::PositionAttrib(), 0.05f);
    ASSERT_GL_NO_ERROR();

    // Create single sampled framebuffer to use as dest.
    GLFramebuffer fboSS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboSS);
    GLTexture colorSS;
    glBindTexture(GL_TEXTURE_2D, colorSS);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, colorSS, 0);
    ASSERT_GL_NO_ERROR();

    // Bind MS to READ as SS is already bound to DRAW.
    glBindFramebuffer(GL_READ_FRAMEBUFFER, fboMS);
    glBlitFramebuffer(0, 0, kSize, kSize, 0, 0, kSize, kSize, GL_COLOR_BUFFER_BIT, GL_NEAREST);
    ASSERT_GL_NO_ERROR();

    // Bind SS to READ so we can readPixels from it
    glBindFramebuffer(GL_FRAMEBUFFER, fboSS);

    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(0, kSize - 1, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, kSize - 1, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kSize / 2, kSize / 2, GLColor::red);
    ASSERT_GL_NO_ERROR();
}

// BlitFramebuffer functionality test. ES3+.
TEST_P(MSRTTES3Test, BlitFramebufferTest)
{
    blitFramebufferTestCommon(false);
}

// BlitFramebuffer functionality test with renderbuffer. ES3+.
TEST_P(MSRTTES3Test, RenderbufferBlitFramebufferTest)
{
    blitFramebufferTestCommon(true);
}

// GenerateMipmap functionality test
TEST_P(MSRTTTest, GenerateMipmapTest)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    constexpr GLsizei kSize = 64;

    setupCopyTexProgram();
    glUseProgram(mCopyTextureProgram);

    // Initialize texture with blue
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, kSize, kSize, 0, GL_RGB, GL_UNSIGNED_BYTE, nullptr);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

    GLFramebuffer FBO;
    glBindFramebuffer(GL_FRAMEBUFFER, FBO);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, 4);
    ASSERT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);
    glClearColor(0.0f, 0.0f, 1.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);
    glViewport(0, 0, kSize, kSize);
    glBindFramebuffer(GL_FRAMEBUFFER, 0);
    ASSERT_GL_NO_ERROR();

    // Generate mipmap
    glGenerateMipmap(GL_TEXTURE_2D);
    ASSERT_GL_NO_ERROR();

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);

    // Now draw the texture to various different sized areas.
    clearAndDrawQuad(mCopyTextureProgram, kSize, kSize);
    EXPECT_PIXEL_COLOR_EQ(kSize / 2, kSize / 2, GLColor::blue);

    // Use mip level 1
    clearAndDrawQuad(mCopyTextureProgram, kSize / 2, kSize / 2);
    EXPECT_PIXEL_COLOR_EQ(kSize / 4, kSize / 4, GLColor::blue);

    // Use mip level 2
    clearAndDrawQuad(mCopyTextureProgram, kSize / 4, kSize / 4);
    EXPECT_PIXEL_COLOR_EQ(kSize / 8, kSize / 8, GLColor::blue);

    ASSERT_GL_NO_ERROR();
}

void MSRTTTest::drawCopyThenBlendCommon(bool useRenderbuffer)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    constexpr GLsizei kSize = 64;

    setupCopyTexProgram();

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    // Create multisampled framebuffer to draw into
    GLTexture textureMS;
    GLRenderbuffer renderbufferMS;
    createAndAttachColorAttachment(useRenderbuffer, kSize, GL_COLOR_ATTACHMENT0, nullptr,
                                   mTestSampleCount, &textureMS, &renderbufferMS);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Draw red into the multisampled color buffer.
    ANGLE_GL_PROGRAM(drawColor, essl1_shaders::vs::Simple(), essl1_shaders::fs::UniformColor());
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);

    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Create a texture and copy into it.
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 0, 0, kSize, kSize, 0);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

    // Draw again into the framebuffer, this time blending.  This tests that the framebuffer's data,
    // residing in the single-sampled texture, is available to the multisampled intermediate image
    // for blending.

    // Blend half-transparent green into the multisampled color buffer.
    glUniform4f(colorUniformLocation, 0.0f, 1.0f, 0.0f, 0.5f);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Verify that the texture is now yellow
    const GLColor kExpected(127, 127, 0, 191);
    EXPECT_PIXEL_COLOR_NEAR(0, 0, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, 0, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(0, kSize - 1, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, kSize - 1, kExpected, 1);

    // For completeness, verify that the texture used as copy target is red.
    ASSERT_GL_NO_ERROR();
    verifyResults(texture, GLColor::red, kSize, 0, 0, kSize, kSize);

    ASSERT_GL_NO_ERROR();
}

// Draw, copy, then blend.  The copy will make sure an implicit resolve happens.  Regardless, the
// following draw should retain the data written by the first draw command.
TEST_P(MSRTTTest, DrawCopyThenBlend)
{
    drawCopyThenBlendCommon(false);
}

// Draw, copy, then blend.  The copy will make sure an implicit resolve happens.  Regardless, the
// following draw should retain the data written by the first draw command.  Uses renderbuffer.
TEST_P(MSRTTTest, RenderbufferDrawCopyThenBlend)
{
    drawCopyThenBlendCommon(true);
}

void MSRTTTest::clearDrawCopyThenBlendSameProgramCommon(bool useRenderbuffer)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    constexpr GLsizei kSize = 64;

    setupCopyTexProgram();

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    // Create multisampled framebuffer to draw into
    GLTexture textureMS;
    GLRenderbuffer renderbufferMS;
    createAndAttachColorAttachment(useRenderbuffer, kSize, GL_COLOR_ATTACHMENT0, nullptr,
                                   mTestSampleCount, &textureMS, &renderbufferMS);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Draw red into the multisampled color buffer.
    ANGLE_GL_PROGRAM(drawColor, essl1_shaders::vs::Simple(), essl1_shaders::fs::UniformColor());
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);

    // Clear the framebuffer.
    glClearColor(0.1f, 0.9f, 0.2f, 0.8f);
    glClear(GL_COLOR_BUFFER_BIT);

    // Then draw into it.
    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Blend green into it.  This makes sure that the blend after the resolve doesn't have different
    // state from the one used here.
    glEnable(GL_BLEND);
    glBlendFunc(GL_ONE, GL_ONE);
    glUniform4f(colorUniformLocation, 0.0f, 1.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Create a texture and copy into it.
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 0, 0, kSize, kSize, 0);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

    // Draw again into the framebuffer, this time blending.  This tests that the framebuffer's data,
    // residing in the single-sampled texture, is available to the multisampled intermediate image
    // for blending.

    // Blend blue into the multisampled color buffer.
    glUniform4f(colorUniformLocation, 0.0f, 0.0f, 1.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Verify that the texture is now white
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::white);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, 0, GLColor::white);
    EXPECT_PIXEL_COLOR_EQ(0, kSize - 1, GLColor::white);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, kSize - 1, GLColor::white);

    // Once again, clear and draw so the program is used again in the way it was first used.
    glClear(GL_COLOR_BUFFER_BIT);
    glDisable(GL_BLEND);
    glUniform4f(colorUniformLocation, 0.0f, 0.0f, 1.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);

    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, 0, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(0, kSize - 1, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, kSize - 1, GLColor::blue);

    // For completeness, verify that the texture used as copy target is yellow.
    ASSERT_GL_NO_ERROR();
    verifyResults(texture, GLColor::yellow, kSize, 0, 0, kSize, kSize);

    ASSERT_GL_NO_ERROR();
}

// Clear&Draw, copy, then blend with same program.  The copy will make sure an implicit resolve
// happens.  The second draw should retain the data written by the first draw command ("unresolve"
// operation).  The same program is used for the first and second draw calls, and the fact that the
// attachment is cleared or unresolved should not cause issues.  In the Vulkan backend, the program
// will be used in different subpass indices, so two graphics pipelines should be created for it.
TEST_P(MSRTTTest, ClearDrawCopyThenBlendSameProgram)
{
    clearDrawCopyThenBlendSameProgramCommon(false);
}

// Same as ClearDrawCopyThenBlendSameProgram but with renderbuffers
TEST_P(MSRTTTest, RenderbufferClearDrawCopyThenBlendSameProgram)
{
    clearDrawCopyThenBlendSameProgramCommon(true);
}

// Similar to RenderbufferClearDrawCopyThenBlendSameProgram, but with the depth/stencil attachment
// being unresolved only.
TEST_P(MSRTTES3Test, RenderbufferClearDrawCopyThenBlendWithDepthStencilSameProgram)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    constexpr GLsizei kSize = 64;

    setupCopyTexProgram();

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    // Create multisampled framebuffer to draw into
    GLTexture color;
    glBindTexture(GL_TEXTURE_2D, color);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, color,
                                         0, 4);

    GLRenderbuffer depthStencil;
    glBindRenderbuffer(GL_RENDERBUFFER, depthStencil);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_DEPTH24_STENCIL8, kSize, kSize);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER,
                              depthStencil);
    ASSERT_GL_NO_ERROR();
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Draw red into the multisampled color buffer.
    ANGLE_GL_PROGRAM(drawColor, essl1_shaders::vs::Simple(), essl1_shaders::fs::UniformColor());
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);

    // Enable write to depth/stencil so the attachment has valid contents, but always pass the test.
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_ALWAYS);

    glEnable(GL_STENCIL_TEST);
    glStencilFunc(GL_ALWAYS, 0x55, 0xFF);
    glStencilOp(GL_REPLACE, GL_REPLACE, GL_REPLACE);
    glStencilMask(0xFF);

    // Clear the framebuffer.
    glClearColor(0.1f, 0.9f, 0.2f, 0.8f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);

    // Then draw into it.
    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 1.0f);
    ASSERT_GL_NO_ERROR();

    // Blend green into it.  This makes sure that the blend after the resolve doesn't have different
    // state from the one used here.  Additionally, test that the previous draw output the correct
    // depth/stencil data.  Again, this makes sure that the draw call after the resolve doesn't have
    // different has depth/stencil test state.

    // If depth is not set to 1, rendering would fail.
    glDepthFunc(GL_LESS);

    // If stencil is not set to 0x55, rendering would fail.
    glStencilFunc(GL_EQUAL, 0x55, 0xFF);
    glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);

    glEnable(GL_BLEND);
    glBlendFunc(GL_ONE, GL_ONE);
    glUniform4f(colorUniformLocation, 0.0f, 1.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.95f);
    ASSERT_GL_NO_ERROR();

    // Create a texture and copy into it.
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 0, 0, kSize, kSize, 0);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

    // Clear color (but not depth/stencil), and draw again into the framebuffer, this time blending.
    // Additionally, make sure the depth/stencil data are retained.

    // Clear color (to blue), but not depth/stencil.
    glClearColor(0.0f, 0.0f, 1.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);

    // Blend green into the multisampled color buffer.
    glUniform4f(colorUniformLocation, 0.0f, 1.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.9f);
    ASSERT_GL_NO_ERROR();

    // Verify that the texture is now cyan
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::cyan);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, 0, GLColor::cyan);
    EXPECT_PIXEL_COLOR_EQ(0, kSize - 1, GLColor::cyan);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, kSize - 1, GLColor::cyan);

    // Once again, clear and draw so the program is used again in the way it was first used.
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
    glDisable(GL_BLEND);
    glDepthFunc(GL_ALWAYS);
    glStencilFunc(GL_ALWAYS, 0x55, 0xFF);
    glStencilOp(GL_REPLACE, GL_REPLACE, GL_REPLACE);
    glUniform4f(colorUniformLocation, 0.0f, 0.0f, 1.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);

    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, 0, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(0, kSize - 1, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, kSize - 1, GLColor::blue);

    // For completeness, verify that the texture used as copy target is yellow.
    ASSERT_GL_NO_ERROR();
    verifyResults(texture, GLColor::yellow, kSize, 0, 0, kSize, kSize);

    ASSERT_GL_NO_ERROR();
}

void MSRTTTest::drawCopyDrawThenMaskedClearCommon(bool useRenderbuffer)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    constexpr GLsizei kSize = 64;

    setupCopyTexProgram();

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    // Create multisampled framebuffer to draw into
    GLTexture textureMS;
    GLRenderbuffer renderbufferMS;
    createAndAttachColorAttachment(useRenderbuffer, kSize, GL_COLOR_ATTACHMENT0, nullptr,
                                   mTestSampleCount, &textureMS, &renderbufferMS);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Draw red into the multisampled color buffer.
    ANGLE_GL_PROGRAM(drawColor, essl1_shaders::vs::Simple(), essl1_shaders::fs::UniformColor());
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);

    // Draw into framebuffer.
    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Create a texture and copy into it.
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 0, 0, kSize, kSize, 0);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

    // Draw again into the framebuffer, this time blending.  Afterwards, issue a masked clear.  This
    // ensures that previous resolved data is unresolved, and mid-render-pass clears work correctly.

    // Draw green into the multisampled color buffer.
    glUniform4f(colorUniformLocation, 0.0f, 1.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Issue a masked clear.
    glClearColor(0.1f, 0.9f, 1.0f, 0.8f);
    glColorMask(GL_FALSE, GL_FALSE, GL_TRUE, GL_FALSE);
    glClear(GL_COLOR_BUFFER_BIT);

    // Verify that the texture is now cyan
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::cyan);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, 0, GLColor::cyan);
    EXPECT_PIXEL_COLOR_EQ(0, kSize - 1, GLColor::cyan);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, kSize - 1, GLColor::cyan);

    // For completeness, verify that the texture used as copy target is red.
    ASSERT_GL_NO_ERROR();
    verifyResults(texture, GLColor::red, kSize, 0, 0, kSize, kSize);

    ASSERT_GL_NO_ERROR();
}

// Draw, copy, draw then issue a masked clear.  The copy will make sure an implicit resolve
// happens.  The second draw should retain the data written by the first draw command ("unresolve"
// operation).  The final clear uses a draw call to perform the clear in the Vulkan backend, and it
// should use the correct subpass index.
TEST_P(MSRTTTest, DrawCopyDrawThenMaskedClear)
{
    drawCopyDrawThenMaskedClearCommon(false);
}

// Same as DrawCopyDrawThenMaskedClearCommon but with renderbuffers
TEST_P(MSRTTTest, RenderbufferDrawCopyDrawThenMaskedClear)
{
    drawCopyDrawThenMaskedClearCommon(true);
}

void MSRTTES3Test::drawCopyDrawAttachInvalidatedThenDrawCommon(bool useRenderbuffer)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    constexpr GLsizei kSize = 64;

    setupCopyTexProgram();

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    // Create multisampled framebuffer to draw into
    GLTexture textureMS;
    GLRenderbuffer renderbufferMS;
    createAndAttachColorAttachment(useRenderbuffer, kSize, GL_COLOR_ATTACHMENT0, nullptr,
                                   mTestSampleCount, &textureMS, &renderbufferMS);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Draw red into the multisampled color buffer.
    ANGLE_GL_PROGRAM(drawColor, essl1_shaders::vs::Simple(), essl1_shaders::fs::UniformColor());
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);

    // Clear and draw into framebuffer.
    glClear(GL_COLOR_BUFFER_BIT);
    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Create a texture and copy into it.
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 0, 0, kSize, kSize, 0);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

    // Draw green into framebuffer.  This will unresolve color.
    glUniform4f(colorUniformLocation, 0.0f, 1.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Create multisampled framebuffer and invalidate its attachment.
    GLFramebuffer invalidateFboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, invalidateFboMS);

    // Create multisampled framebuffer to draw into
    GLTexture invalidateTextureMS;
    GLRenderbuffer invalidateRenderbufferMS;
    createAndAttachColorAttachment(useRenderbuffer, kSize, GL_COLOR_ATTACHMENT0, nullptr,
                                   mTestSampleCount, &invalidateTextureMS,
                                   &invalidateRenderbufferMS);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Invalidate the attachment.
    GLenum invalidateAttachments[] = {GL_COLOR_ATTACHMENT0};
    glInvalidateFramebuffer(GL_FRAMEBUFFER, 1, invalidateAttachments);

    // Replace the original framebuffer's attachment with the invalidated one.
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);
    if (useRenderbuffer)
    {
        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER,
                                  invalidateRenderbufferMS);
    }
    else
    {
        glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                             invalidateTextureMS, 0, 4);
    }
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Draw blue into the multisampled color buffer.
    glUniform4f(colorUniformLocation, 0.0f, 0.0f, 1.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Verify that the texture is now blue
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, 0, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(0, kSize - 1, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, kSize - 1, GLColor::blue);

    // For completeness, verify that the texture used as copy target is red.
    ASSERT_GL_NO_ERROR();
    verifyResults(texture, GLColor::red, kSize, 0, 0, kSize, kSize);

    ASSERT_GL_NO_ERROR();
}

// Draw, copy, draw, attach an invalidated image then draw.  The second draw will need to unresolve
// color.  Attaching an invalidated image changes the framebuffer, and the following draw doesn't
// require an unresolve.  In the Vulkan backend, mismatches in unresolve state between framebuffer
// and render pass will result in an ASSERT.
TEST_P(MSRTTES3Test, DrawCopyDrawAttachInvalidatedThenDraw)
{
    drawCopyDrawAttachInvalidatedThenDrawCommon(false);
}

// Same as DrawCopyDrawAttachInvalidatedThenDraw but with renderbuffers
TEST_P(MSRTTES3Test, RenderbufferDrawCopyDrawAttachInvalidatedThenDraw)
{
    drawCopyDrawAttachInvalidatedThenDrawCommon(true);
}

// Draw with a stencil-only attachment once without needing to unresolve it, and once needing to.
// Regression test for a bug in the Vulkan backend where the state of stencil unresolve attachment's
// existence was masked out by mistake in the framebuffer cache key, so the same framebuffer object
// was used for both render passes, even though they could have different subpass counts due to
// stencil unresolve.
TEST_P(MSRTTES3Test, RenderbufferDrawStencilThenUnresolveStencil)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    constexpr GLsizei kSize = 64;

    setupCopyTexProgram();

    ANGLE_GL_PROGRAM(drawColor, essl1_shaders::vs::Simple(), essl1_shaders::fs::UniformColor());
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    // Create multisampled framebuffer to draw into
    GLTexture textureMS;
    createAndAttachColorAttachment(false, kSize, GL_COLOR_ATTACHMENT0, nullptr, mTestSampleCount,
                                   &textureMS, nullptr);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    GLRenderbuffer dsRenderbufferMS;
    glBindRenderbuffer(GL_RENDERBUFFER, dsRenderbufferMS);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, mTestSampleCount, GL_STENCIL_INDEX8, kSize,
                                        kSize);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_RENDERBUFFER,
                              dsRenderbufferMS);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Draw red once with stencil cleared, not needing unresolve
    glClearColor(0.1, 0.2, 0.3, 0.4);
    glClearStencil(0);
    glClear(GL_COLOR_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);

    glEnable(GL_STENCIL_TEST);
    glStencilFunc(GL_ALWAYS, 0x55, 0xFF);
    glStencilOp(GL_REPLACE, GL_REPLACE, GL_REPLACE);
    glStencilMask(0xFF);

    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 1.0f);
    ASSERT_GL_NO_ERROR();

    // Create a texture and copy color into it, this breaks the render pass
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 0, 0, kSize, kSize, 0);

    // Clear the color, so that only stencil needs unresolving.
    glClear(GL_COLOR_BUFFER_BIT);

    // Draw green, expecting correct stencil.  This unresolves stencil.
    glStencilFunc(GL_EQUAL, 0x55, 0xFF);
    glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);

    glUniform4f(colorUniformLocation, 0.0f, 1.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 1.0f);
    ASSERT_GL_NO_ERROR();

    // Verify that the texture is now green
    verifyResults(textureMS, GLColor::green, kSize, 0, 0, kSize, kSize);

    // For completeness, also verify that the copy texture is red
    verifyResults(texture, GLColor::red, kSize, 0, 0, kSize, kSize);

    ASSERT_GL_NO_ERROR();
}

void MSRTTES3Test::drawCopyDrawAttachDepthStencilClearThenDrawCommon(bool useRenderbuffer)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    // Use glFramebufferTexture2DMultisampleEXT for depth/stencil texture is only supported with
    // GL_EXT_multisampled_render_to_texture2.
    ANGLE_SKIP_TEST_IF(!useRenderbuffer &&
                       !EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture2"));
    constexpr GLsizei kSize = 64;

    setupCopyTexProgram();

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    // Create multisampled framebuffer to draw into
    GLTexture textureMS;
    GLRenderbuffer renderbufferMS;
    createAndAttachColorAttachment(useRenderbuffer, kSize, GL_COLOR_ATTACHMENT0, nullptr,
                                   mTestSampleCount, &textureMS, &renderbufferMS);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Draw red into the multisampled color buffer.
    ANGLE_GL_PROGRAM(drawColor, essl1_shaders::vs::Simple(), essl1_shaders::fs::UniformColor());
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);

    // Clear and draw into framebuffer.  There is no unresolve due to clear.  The clear value is
    // irrelevant as the contents are immediately overdrawn with the draw call.
    glClear(GL_COLOR_BUFFER_BIT);
    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Create a texture and copy into it.
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 0, 0, kSize, kSize, 0);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

    // Draw green into framebuffer.  This will unresolve color.
    glUniform4f(colorUniformLocation, 0.0f, 1.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Attach a depth/stencil attachment.
    GLTexture dsTextureMS;
    GLRenderbuffer dsRenderbufferMS;
    createAndAttachDepthStencilAttachment(useRenderbuffer, kSize, &dsTextureMS, &dsRenderbufferMS);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Clear all attachments, so no unresolve would be necessary.
    glClearColor(0.0f, 0.0f, 1.0f, 1.0f);
    glClearDepthf(1);
    glClearStencil(0x55);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);

    // If depth is not cleared to 1, rendering would fail.
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_LESS);

    // If stencil is not cleared to 0x55, rendering would fail.
    glEnable(GL_STENCIL_TEST);
    glStencilFunc(GL_EQUAL, 0x55, 0xFF);
    glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
    glStencilMask(0xFF);

    // Blend half-transparent green into the multisampled color buffer.
    glUniform4f(colorUniformLocation, 0.0f, 1.0f, 0.0f, 0.5f);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.95f);
    ASSERT_GL_NO_ERROR();

    // Verify that the texture is now cyan
    const GLColor kExpected2(0, 127, 127, 191);
    EXPECT_PIXEL_COLOR_NEAR(0, 0, kExpected2, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, 0, kExpected2, 1);
    EXPECT_PIXEL_COLOR_NEAR(0, kSize - 1, kExpected2, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, kSize - 1, kExpected2, 1);

    // For completeness, verify that the texture used as copy target is red.
    ASSERT_GL_NO_ERROR();
    verifyResults(texture, GLColor::red, kSize, 0, 0, kSize, kSize);

    ASSERT_GL_NO_ERROR();
}

// Draw, copy, draw, attach depth/stencil, clear then draw.  The second draw will need to unresolve
// color.  Attaching depth/stencil changes the framebuffer, and the following clear ensures no
// unresolve is necessary.  In the Vulkan backend, mismatches in unresolve state between framebuffer
// and render pass will result in an ASSERT.
TEST_P(MSRTTES3Test, DrawCopyDrawAttachDepthStencilClearThenDraw)
{
    drawCopyDrawAttachDepthStencilClearThenDrawCommon(false);
}

// Same as DrawCopyDrawAttachDepthStencilClearThenDraw but with renderbuffers
TEST_P(MSRTTES3Test, RenderbufferDrawCopyDrawAttachDepthStencilClearThenDraw)
{
    drawCopyDrawAttachDepthStencilClearThenDrawCommon(true);
}

// Draw, copy, redefine the color attachment with a different format, clear, copy then draw.  The
// initial draw will need to unresolve color as the color attachment is preinitilized with data.
// Redefining the color attachment forces framebuffer to recreate when the clear is called.  The
// second copy resolves the clear and the final draw unresolves again.  In the Vulkan backend,
// mismatches in unresolve state between framebuffer and render pass will result in an ASSERT and a
// validation error (if ASSERT is removed).
TEST_P(MSRTTES3Test, DrawCopyRedefineClearCopyThenDraw)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    constexpr GLsizei kSize = 64;

    setupCopyTexProgram();

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    std::vector<GLColor> initialColorData(kSize * kSize, GLColor::black);

    // Create multisampled framebuffer to draw into
    GLTexture colorMS;
    glBindTexture(GL_TEXTURE_2D, colorMS);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE,
                 initialColorData.data());
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         colorMS, 0, 4);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Draw red into the multisampled color buffer.
    ANGLE_GL_PROGRAM(drawColor, essl1_shaders::vs::Simple(), essl1_shaders::fs::UniformColor());
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);

    // Draw into framebuffer.  This will unresolve color.
    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Create a texture and copy into it.
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 0, 0, kSize, kSize, 0);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

    // Incompatibly redefine the texture, forcing its image to be recreated.
    glBindTexture(GL_TEXTURE_2D, colorMS);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, kSize, kSize, 0, GL_RGB, GL_UNSIGNED_BYTE, nullptr);
    ASSERT_GL_NO_ERROR();
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    glClearColor(0.0f, 1.0f, 0.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);

    // Create another texture and copy into it.
    GLTexture texture2;
    glBindTexture(GL_TEXTURE_2D, texture2);
    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 0, 0, kSize, kSize, 0);

    // Clear to green and blend blue into the multisampled color buffer.
    glUseProgram(drawColor);
    glUniform4f(colorUniformLocation, 0.0f, 0.0f, 1.0f, 1.0f);
    glEnable(GL_BLEND);
    glBlendFunc(GL_ONE, GL_ONE);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Verify that the texture is now cyan
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::cyan);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, 0, GLColor::cyan);
    EXPECT_PIXEL_COLOR_EQ(0, kSize - 1, GLColor::cyan);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, kSize - 1, GLColor::cyan);

    // For completeness, verify that the texture used as copy target is red.
    ASSERT_GL_NO_ERROR();
    verifyResults(texture, GLColor::red, kSize, 0, 0, kSize, kSize);

    ASSERT_GL_NO_ERROR();
}

// Draw, copy, rebind the attachment, clear then draw.  The initial draw will need to unresolve
// color.  The framebuffer attachment is temporary changed and then reset back to the original.
// This causes the framebuffer to be recreated on the following clear and draw.  The clear prevents
// the final draw from doing an unresolve.  In the Vulkan backend, mismatches in unresolve state
// between framebuffer and render pass will result in an ASSERT and a validation error (if ASSERT is
// removed).
TEST_P(MSRTTES3Test, DrawCopyRebindAttachmentClearThenDraw)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    constexpr GLsizei kSize = 64;

    setupCopyTexProgram();

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    std::vector<GLColor> initialColorData(kSize * kSize, GLColor::black);

    // Create multisampled framebuffer to draw into
    GLTexture colorMS;
    glBindTexture(GL_TEXTURE_2D, colorMS);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE,
                 initialColorData.data());
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         colorMS, 0, 4);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Draw red into the multisampled color buffer.
    ANGLE_GL_PROGRAM(drawColor, essl1_shaders::vs::Simple(), essl1_shaders::fs::UniformColor());
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);

    // Draw into framebuffer.  This will unresolve color.
    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Create a texture and copy into it.
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 0, 0, kSize, kSize, 0);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

    // Bind the framebuffer to another texture.
    GLTexture color;
    glBindTexture(GL_TEXTURE_2D, color);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, color, 0);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Do whatever.
    glClear(GL_COLOR_BUFFER_BIT);

    // Rebind the framebuffer back to the original texture.
    glBindTexture(GL_TEXTURE_2D, colorMS);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         colorMS, 0, 4);

    // Clear to green and blend blue into the multisampled color buffer.
    glClearColor(0.0f, 1.0f, 0.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);
    glUseProgram(drawColor);
    glUniform4f(colorUniformLocation, 0.0f, 0.0f, 1.0f, 1.0f);
    glEnable(GL_BLEND);
    glBlendFunc(GL_ONE, GL_ONE);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Verify that the texture is now cyan
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::cyan);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, 0, GLColor::cyan);
    EXPECT_PIXEL_COLOR_EQ(0, kSize - 1, GLColor::cyan);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, kSize - 1, GLColor::cyan);

    // For completeness, verify that the texture used as copy target is red.
    ASSERT_GL_NO_ERROR();
    verifyResults(texture, GLColor::red, kSize, 0, 0, kSize, kSize);

    ASSERT_GL_NO_ERROR();
}

void MSRTTTest::clearThenBlendCommon(bool useRenderbuffer)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    constexpr GLsizei kSize = 64;

    setupCopyTexProgram();

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    // Create multisampled framebuffer to draw into
    GLTexture textureMS;
    GLRenderbuffer renderbufferMS;
    createAndAttachColorAttachment(useRenderbuffer, kSize, GL_COLOR_ATTACHMENT0, nullptr,
                                   mTestSampleCount, &textureMS, &renderbufferMS);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Clear the framebuffer.
    glClearColor(1.0f, 0.0f, 0.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);

    // Blend half-transparent green into the multisampled color buffer.
    ANGLE_GL_PROGRAM(drawColor, essl1_shaders::vs::Simple(), essl1_shaders::fs::UniformColor());
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);

    glUniform4f(colorUniformLocation, 0.0f, 1.0f, 0.0f, 0.5f);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Verify that the texture is now yellow
    const GLColor kExpected(127, 127, 0, 191);
    EXPECT_PIXEL_COLOR_NEAR(0, 0, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, 0, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(0, kSize - 1, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, kSize - 1, kExpected, 1);
}

// Clear then blend.  The clear should be applied correctly.
TEST_P(MSRTTTest, ClearThenBlend)
{
    clearThenBlendCommon(false);
}

// Clear then blend.  The clear should be applied correctly.  Uses renderbuffer.
TEST_P(MSRTTTest, RenderbufferClearThenBlend)
{
    clearThenBlendCommon(true);
}

void MSRTTES3Test::depthStencilClearThenDrawCommon(bool useRenderbuffer)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    if (!useRenderbuffer)
    {
        ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture2"));
    }

    constexpr GLsizei kSize = 64;

    setupCopyTexProgram();

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    // Create framebuffer to draw into, with both color and depth attachments.
    GLTexture textureMS;
    GLRenderbuffer renderbufferMS;
    createAndAttachColorAttachment(useRenderbuffer, kSize, GL_COLOR_ATTACHMENT0, nullptr,
                                   mTestSampleCount, &textureMS, &renderbufferMS);

    GLTexture dsTextureMS;
    GLRenderbuffer dsRenderbufferMS;
    createAndAttachDepthStencilAttachment(useRenderbuffer, kSize, &dsTextureMS, &dsRenderbufferMS);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Set viewport and clear depth/stencil
    glViewport(0, 0, kSize, kSize);
    glClearDepthf(1);
    glClearStencil(0x55);
    glClear(GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);

    // If depth is not cleared to 1, rendering would fail.
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_LESS);

    // If stencil is not cleared to 0x55, rendering would fail.
    glEnable(GL_STENCIL_TEST);
    glStencilFunc(GL_EQUAL, 0x55, 0xFF);
    glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
    glStencilMask(0xFF);

    // Set up program
    ANGLE_GL_PROGRAM(drawRed, essl1_shaders::vs::Simple(), essl1_shaders::fs::Red());

    // Draw red
    drawQuad(drawRed, essl1_shaders::PositionAttrib(), 0.0f);
    ASSERT_GL_NO_ERROR();

    // Create a texture and copy into it.
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 0, 0, kSize, kSize, 0);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    ASSERT_GL_NO_ERROR();

    // Verify.
    verifyResults(texture, GLColor::red, kSize, 0, 0, kSize, kSize);
}

// Clear depth stencil, then draw.  The clear should be applied correctly.
TEST_P(MSRTTES3Test, DepthStencilClearThenDraw)
{
    depthStencilClearThenDrawCommon(false);
}

// Clear depth stencil, then draw.  The clear should be applied correctly.  Uses renderbuffer.
TEST_P(MSRTTES3Test, RenderbufferDepthStencilClearThenDraw)
{
    depthStencilClearThenDrawCommon(true);
}

// Clear&Draw, copy, then blend similarly to RenderbufferClearDrawCopyThenBlendSameProgram.  This
// tests uses a depth/stencil buffer and makes sure the second draw (in the second render pass)
// succeeds (i.e. depth/stencil data is not lost).  Note that this test doesn't apply to
// depth/stencil textures as they are explicitly autoinvalidated between render passes.
TEST_P(MSRTTES3Test, RenderbufferDepthStencilClearDrawCopyThenBlend)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    // http://anglebug.com/42263663
    ANGLE_SKIP_TEST_IF(IsLinux() && IsIntel() && IsVulkan());

    constexpr GLsizei kSize = 64;

    setupCopyTexProgram();

    GLFramebuffer fbo;
    glBindFramebuffer(GL_FRAMEBUFFER, fbo);

    // Create framebuffer to draw into, with both color and depth/stencil attachments.
    GLTexture color;
    glBindTexture(GL_TEXTURE_2D, color);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, color,
                                         0, 4);

    GLRenderbuffer depthStencil;
    glBindRenderbuffer(GL_RENDERBUFFER, depthStencil);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_DEPTH24_STENCIL8, kSize, kSize);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER,
                              depthStencil);
    ASSERT_GL_NO_ERROR();
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Set viewport and clear depth/stencil
    glViewport(0, 0, kSize, kSize);
    glClearDepthf(1);
    glClearStencil(0x55);
    glClear(GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);

    // If depth is not cleared to 1, rendering would fail.
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_LESS);

    // If stencil is not cleared to 0x55, rendering would fail.
    glEnable(GL_STENCIL_TEST);
    glStencilFunc(GL_EQUAL, 0x55, 0xFF);
    glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
    glStencilMask(0xFF);

    // Set up program
    ANGLE_GL_PROGRAM(drawColor, essl1_shaders::vs::Simple(), essl1_shaders::fs::UniformColor());
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);

    // Draw red
    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.25f);
    ASSERT_GL_NO_ERROR();

    // Create a texture and copy into it.
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 0, 0, kSize, kSize, 0);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    ASSERT_GL_NO_ERROR();

    // Draw again into the framebuffer, this time blending.  This tests that both the color and
    // depth/stencil data are preserved after the resolve incurred by the copy above.
    glUniform4f(colorUniformLocation, 0.0f, 1.0f, 0.0f, 0.5f);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.0f);
    ASSERT_GL_NO_ERROR();

    // Verify that the texture is now yellow
    const GLColor kExpected(127, 127, 0, 191);
    EXPECT_PIXEL_COLOR_NEAR(0, 0, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, 0, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(0, kSize - 1, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, kSize - 1, kExpected, 1);

    // For completeness, verify that the texture used as copy target is red.
    verifyResults(texture, GLColor::red, kSize, 0, 0, kSize, kSize);
}

// Draw, copy, then clear&blend.  This tests uses a depth/stencil buffer and makes sure the second
// draw (in the second render pass) succeeds (i.e.  depth/stencil data is not lost).  The difference
// with RenderbufferDepthStencilClearDrawCopyThenBlend is that color is cleared in the second render
// pass, so only depth/stencil data is unresolved.  This test doesn't apply to depth/stencil
// textures as they are explicitly autoinvalidated between render passes.
TEST_P(MSRTTES3Test, RenderbufferDepthStencilDrawCopyClearThenBlend)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    // http://anglebug.com/42263663
    ANGLE_SKIP_TEST_IF(IsLinux() && IsIntel() && IsVulkan());

    constexpr GLsizei kSize = 64;

    setupCopyTexProgram();

    GLFramebuffer fbo;
    glBindFramebuffer(GL_FRAMEBUFFER, fbo);

    // Create framebuffer to draw into, with both color and depth/stencil attachments.
    GLTexture color;
    glBindTexture(GL_TEXTURE_2D, color);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, color,
                                         0, 4);

    GLRenderbuffer depthStencil;
    glBindRenderbuffer(GL_RENDERBUFFER, depthStencil);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_DEPTH24_STENCIL8, kSize, kSize);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER,
                              depthStencil);
    ASSERT_GL_NO_ERROR();
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Set viewport and clear depth/stencil through draw
    glViewport(0, 0, kSize, kSize);

    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_ALWAYS);

    glEnable(GL_STENCIL_TEST);
    glStencilFunc(GL_ALWAYS, 0x55, 0xFF);
    glStencilOp(GL_REPLACE, GL_REPLACE, GL_REPLACE);
    glStencilMask(0xFF);

    // Set up program
    ANGLE_GL_PROGRAM(drawColor, essl1_shaders::vs::Simple(), essl1_shaders::fs::UniformColor());
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);

    // Draw red
    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 1.0f);
    ASSERT_GL_NO_ERROR();

    // Create a texture and copy into it.
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 0, 0, kSize, kSize, 0);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    ASSERT_GL_NO_ERROR();

    // Clear color to blue
    glClearColor(0.0, 0.0, 1.0, 1.0);
    glClear(GL_COLOR_BUFFER_BIT);

    // If depth is not cleared to 1, rendering would fail.
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_LESS);

    // If stencil is not cleared to 0x55, rendering would fail.
    glEnable(GL_STENCIL_TEST);
    glStencilFunc(GL_EQUAL, 0x55, 0xFF);
    glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
    glStencilMask(0xFF);

    // Draw again into the framebuffer, this time blending.  This tests that depth/stencil data are
    // preserved after the resolve incurred by the copy above and color is cleared correctly.
    glUniform4f(colorUniformLocation, 0.0f, 1.0f, 0.0f, 0.5f);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.0f);
    ASSERT_GL_NO_ERROR();

    // Copy into the texture again.
    glBindTexture(GL_TEXTURE_2D, texture);
    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 0, 0, kSize, kSize, 0);
    ASSERT_GL_NO_ERROR();

    // Verify that the texture is now cyan
    const GLColor kExpected(0, 127, 127, 191);
    EXPECT_PIXEL_COLOR_NEAR(0, 0, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, 0, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(0, kSize - 1, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, kSize - 1, kExpected, 1);

    // For completeness, verify that the texture used as copy target is also cyan.
    const GLColor expectedCopyResult(0, 127, 127, 191);
    verifyResults(texture, expectedCopyResult, kSize, 0, 0, kSize, kSize);
}

// Clear, then blit depth/stencil with renderbuffers.  This test makes sure depth/stencil blit uses
// the correct image.  Note that this test doesn't apply to depth/stencil textures as they are
// explicitly autoinvalidated between render passes.
TEST_P(MSRTTES3Test, RenderbufferClearThenBlitDepthStencil)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    constexpr GLsizei kSize = 64;

    setupCopyTexProgram();

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    // Create framebuffer to draw into, with both color and depth/stencil attachments.
    GLTexture color;
    glBindTexture(GL_TEXTURE_2D, color);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, color,
                                         0, 4);

    GLRenderbuffer depthStencilMS;
    glBindRenderbuffer(GL_RENDERBUFFER, depthStencilMS);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_DEPTH24_STENCIL8, kSize, kSize);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER,
                              depthStencilMS);
    ASSERT_GL_NO_ERROR();
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Clear depth/stencil
    glClearDepthf(1);
    glClearStencil(0x55);
    glClear(GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);

    // Create framebuffer as blit target.
    GLFramebuffer fbo;
    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, fbo);

    glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, color, 0);

    GLRenderbuffer depthStencil;
    glBindRenderbuffer(GL_RENDERBUFFER, depthStencil);
    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, kSize, kSize);
    glFramebufferRenderbuffer(GL_DRAW_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER,
                              depthStencil);
    ASSERT_GL_NO_ERROR();
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_DRAW_FRAMEBUFFER);

    // Blit depth/stencil
    glBlitFramebuffer(0, 0, kSize, kSize, 0, 0, kSize, kSize,
                      GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT, GL_NEAREST);

    // Draw into the framebuffer that was the destination of blit, verifying that depth and stencil
    // values are correct.

    // If depth is not 1, rendering would fail.
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_LESS);

    // If stencil is not 0x55, rendering would fail.
    glEnable(GL_STENCIL_TEST);
    glStencilFunc(GL_EQUAL, 0x55, 0xFF);
    glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
    glStencilMask(0xFF);

    // Set up program
    ANGLE_GL_PROGRAM(drawColor, essl1_shaders::vs::Simple(), essl1_shaders::fs::UniformColor());
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);

    // Draw red
    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.0f);
    ASSERT_GL_NO_ERROR();

    // Verify that the texture is now red
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(0, kSize - 1, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, kSize - 1, GLColor::red);

    // Clear depth/stencil to a different value, and blit again but this time flipped.
    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, fboMS);
    glClearDepthf(0);
    glClearStencil(0x3E);
    glClear(GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);

    // Blit
    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, fbo);
    glBlitFramebuffer(0, 0, kSize, kSize, kSize, kSize, 0, 0,
                      GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT, GL_NEAREST);

    // Draw green
    glDepthFunc(GL_GREATER);
    glStencilFunc(GL_EQUAL, 0x3E, 0xFF);
    glUniform4f(colorUniformLocation, 0.0f, 1.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.0f);
    ASSERT_GL_NO_ERROR();

    // Verify that the texture is now green
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, 0, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(0, kSize - 1, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, kSize - 1, GLColor::green);
}

// Draw, then blit depth/stencil with renderbuffers.  This test makes sure depth/stencil resolve is
// correctly implemented.  Note that this test doesn't apply to depth/stencil textures as they are
// explicitly autoinvalidated between render passes.
TEST_P(MSRTTES3Test, RenderbufferDrawThenBlitDepthStencil)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    // http://anglebug.com/42263663
    ANGLE_SKIP_TEST_IF(IsLinux() && IsIntel() && IsVulkan());

    constexpr GLsizei kSize = 64;

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    // Create framebuffer to draw into, with both color and depth/stencil attachments.
    GLTexture color;
    glBindTexture(GL_TEXTURE_2D, color);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, color,
                                         0, 4);

    GLRenderbuffer depthStencilMS;
    glBindRenderbuffer(GL_RENDERBUFFER, depthStencilMS);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_DEPTH24_STENCIL8, kSize, kSize);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER,
                              depthStencilMS);
    ASSERT_GL_NO_ERROR();
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Set up program
    ANGLE_GL_PROGRAM(drawColor, essl1_shaders::vs::Simple(), essl1_shaders::fs::UniformColor());
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);

    // Output depth/stencil through draw
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_ALWAYS);

    glEnable(GL_STENCIL_TEST);
    glStencilFunc(GL_ALWAYS, 0x55, 0xFF);
    glStencilOp(GL_REPLACE, GL_REPLACE, GL_REPLACE);
    glStencilMask(0xFF);

    // Draw blue
    glUniform4f(colorUniformLocation, 0.0f, 0.0f, 1.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 1.0f);
    ASSERT_GL_NO_ERROR();

    // Create framebuffer as blit target.
    GLFramebuffer fbo;
    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, fbo);

    glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, color, 0);

    GLRenderbuffer depthStencil;
    glBindRenderbuffer(GL_RENDERBUFFER, depthStencil);
    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, kSize, kSize);
    glFramebufferRenderbuffer(GL_DRAW_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER,
                              depthStencil);
    ASSERT_GL_NO_ERROR();
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_DRAW_FRAMEBUFFER);

    // Blit depth/stencil
    glBlitFramebuffer(0, 0, kSize, kSize, 0, 0, kSize, kSize,
                      GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT, GL_NEAREST);

    // Draw into the framebuffer that was the destination of blit, verifying that depth and stencil
    // values are correct.

    // If depth is not 1, rendering would fail.
    glDepthFunc(GL_LESS);

    // If stencil is not 0x55, rendering would fail.
    glStencilFunc(GL_EQUAL, 0x55, 0xFF);
    glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
    glStencilMask(0xFF);

    // Draw red
    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.0f);
    ASSERT_GL_NO_ERROR();

    // Verify that the texture is now red
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(0, kSize - 1, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, kSize - 1, GLColor::red);
}

// Makes sure that mixed drawing/reading into/from the same texture using multisampled and single
// sampled framebuffers produce expected results.
TEST_P(MSRTTES3Test, MixedMultisampleSingleSampledDraw)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    constexpr GLsizei kSize = 64;

    // Create render target texture.
    GLTexture color;
    glBindTexture(GL_TEXTURE_2D, color);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

    // Create multisampled framebuffer.
    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, color,
                                         0, 4);
    ASSERT_GL_NO_ERROR();
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Create single sampled framebuffer.
    GLFramebuffer fbo;
    glBindFramebuffer(GL_FRAMEBUFFER, fbo);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, color, 0);
    ASSERT_GL_NO_ERROR();
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Set up program
    ANGLE_GL_PROGRAM(drawColor, essl1_shaders::vs::Simple(), essl1_shaders::fs::UniformColor());
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);

    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    // Draw blue multisampled.
    glUniform4f(colorUniformLocation, 0.0f, 0.0f, 1.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 1.0f);
    ASSERT_GL_NO_ERROR();

    glBindFramebuffer(GL_FRAMEBUFFER, fbo);

    // Draw red single sampled.
    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.0f);
    ASSERT_GL_NO_ERROR();

    // Check that single sampled framebuffer is red.
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(0, kSize - 1, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, kSize - 1, GLColor::red);

    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    // Check that multisampled framebuffer is also red since it uses same texture.
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(0, kSize - 1, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, kSize - 1, GLColor::red);

    glBindFramebuffer(GL_FRAMEBUFFER, fbo);

    // Check that single sampled framebuffer is still red.
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(0, kSize - 1, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, kSize - 1, GLColor::red);

    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    // Draw green multisampled with scissor.
    glEnable(GL_SCISSOR_TEST);
    glScissor(0, 0, kSize / 2, kSize / 2);
    glUniform4f(colorUniformLocation, 0.0f, 1.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 1.0f);
    ASSERT_GL_NO_ERROR();

    glBindFramebuffer(GL_FRAMEBUFFER, fbo);

    // Draw yellow single sampled with scissor.
    glScissor(kSize / 2, kSize / 2, kSize / 2, kSize / 2);
    glUniform4f(colorUniformLocation, 1.0f, 1.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 1.0f);
    ASSERT_GL_NO_ERROR();

    // Check that single sampled framebuffer contains expected colors.
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(0, kSize - 1, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, kSize - 1, GLColor::yellow);
}

// Draw, then blit depth/stencil with renderbuffers, without a color attachment. Note that this test
// doesn't apply to depth/stencil textures as they are explicitly autoinvalidated between render
// passes.
//
// This test first uses a draw call to fill in the depth/stencil buffer, then blits it to force a
// resolve.  Then it uses a no-op draw call to start a "fullscreen" render pass followed by a
// scissored draw to modify parts of the depth buffer:
//
// +--------------------+
// |     D=1, S=0x55    |
// |                    |
// |     +--------+     |
// |     |  D=0   |     |
// |     | S=0xAA |     |
// |     +--------+     |
// |                    |
// |                    |
// +--------------------+
//
// Blit is used again to copy the depth/stencil attachment data, and the result is verified.
TEST_P(MSRTTES3Test, RenderbufferDrawThenBlitDepthStencilOnly)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    // http://anglebug.com/42263663
    ANGLE_SKIP_TEST_IF(IsLinux() && IsIntel() && IsVulkan());

    constexpr GLsizei kSize = 64;

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    // Create framebuffer to draw into, with depth/stencil attachment only.
    GLRenderbuffer depthStencilMS;
    glBindRenderbuffer(GL_RENDERBUFFER, depthStencilMS);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_DEPTH24_STENCIL8, kSize, kSize);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER,
                              depthStencilMS);
    ASSERT_GL_NO_ERROR();
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Set up program
    ANGLE_GL_PROGRAM(drawColor, essl1_shaders::vs::Simple(), essl1_shaders::fs::UniformColor());
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);
    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);

    // Output depth/stencil through draw
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_ALWAYS);

    glEnable(GL_STENCIL_TEST);
    glStencilFunc(GL_ALWAYS, 0x55, 0xFF);
    glStencilOp(GL_REPLACE, GL_REPLACE, GL_REPLACE);
    glStencilMask(0xFF);

    // Draw.  Depth/stencil is now:
    //
    // +--------------------+
    // |     D=1, S=0x55    |
    // |                    |
    // |                    |
    // |                    |
    // |                    |
    // |                    |
    // |                    |
    // |                    |
    // +--------------------+
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 1.0f);
    ASSERT_GL_NO_ERROR();

    // Create framebuffer as blit target.
    GLFramebuffer fbo;
    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, fbo);

    GLRenderbuffer depthStencil;
    glBindRenderbuffer(GL_RENDERBUFFER, depthStencil);
    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, kSize, kSize);
    glFramebufferRenderbuffer(GL_DRAW_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER,
                              depthStencil);
    ASSERT_GL_NO_ERROR();
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_DRAW_FRAMEBUFFER);

    // Blit depth/stencil
    glBlitFramebuffer(0, 0, kSize, kSize, 0, 0, kSize, kSize,
                      GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT, GL_NEAREST);

    // Disable depth/stencil and draw again.  Depth/stencil is not modified.
    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, fboMS);
    glDisable(GL_DEPTH_TEST);
    glDisable(GL_STENCIL_TEST);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.0f);
    ASSERT_GL_NO_ERROR();

    // Enable depth/stencil and do a scissored draw.  Depth/stencil is now:
    //
    // +--------------------+
    // |     D=1, S=0x55    |
    // |                    |
    // |     +--------+     |
    // |     |  D=0   |     |
    // |     | S=0xAA |     |
    // |     +--------+     |
    // |                    |
    // |                    |
    // +--------------------+
    glEnable(GL_DEPTH_TEST);
    glEnable(GL_STENCIL_TEST);
    glStencilFunc(GL_ALWAYS, 0xAA, 0xFF);
    glEnable(GL_SCISSOR_TEST);
    glScissor(kSize / 4, kSize / 4, kSize / 2, kSize / 2);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), -1.0f);
    glDisable(GL_SCISSOR_TEST);
    ASSERT_GL_NO_ERROR();

    // Blit depth/stencil again.
    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, fbo);
    glBlitFramebuffer(0, 0, kSize, kSize, 0, 0, kSize, kSize,
                      GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT, GL_NEAREST);
    ASSERT_GL_NO_ERROR();

    // Draw into the framebuffer that was the destination of blit, verifying that depth and stencil
    // values are correct.
    GLTexture color;
    glBindTexture(GL_TEXTURE_2D, color);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, color, 0);
    ASSERT_GL_NO_ERROR();
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_DRAW_FRAMEBUFFER);

    // First, verify the outside border, where D=1 and S=0x55
    glDepthFunc(GL_LESS);
    glStencilFunc(GL_EQUAL, 0x55, 0xFF);
    glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
    glStencilMask(0xFF);
    ASSERT_GL_NO_ERROR();

    // Draw green
    glUniform4f(colorUniformLocation, 0.0f, 1.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.95f);
    ASSERT_GL_NO_ERROR();

    // Then, verify the center, where D=0 and S=0xAA
    glDepthFunc(GL_GREATER);
    glStencilFunc(GL_EQUAL, 0xAA, 0xFF);
    glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
    glStencilMask(0xFF);

    // Draw blue
    glUniform4f(colorUniformLocation, 0.0f, 0.0f, 1.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), -0.95f);
    ASSERT_GL_NO_ERROR();

    // Verify that the border is now green
    glBindFramebuffer(GL_READ_FRAMEBUFFER, fbo);
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, 0, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(0, kSize - 1, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, kSize - 1, GLColor::green);

    // Verify that the center is now blue
    EXPECT_PIXEL_COLOR_EQ(kSize / 4, kSize / 4, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(3 * kSize / 4 - 1, kSize / 4, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(kSize / 4, 3 * kSize / 4 - 1, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(3 * kSize / 4 - 1, 3 * kSize / 4 - 1, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(kSize / 2, kSize / 2, GLColor::blue);
}

// Test the depth read/write mode change within the renderpass while there is color unresolve
// attachment
TEST_P(MSRTTTest, DepthReadWriteToggleWithStartedRenderPass)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    constexpr GLsizei kSize = 64;

    setupCopyTexProgram();

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    // Create framebuffer to draw into, with both color and depth attachments.
    GLTexture textureMS;
    GLRenderbuffer renderbufferMS;
    createAndAttachColorAttachment(true, kSize, GL_COLOR_ATTACHMENT0, nullptr, mTestSampleCount,
                                   &textureMS, &renderbufferMS);

    GLTexture dsTextureMS;
    GLRenderbuffer dsRenderbufferMS;
    glBindRenderbuffer(GL_RENDERBUFFER, dsRenderbufferMS);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_DEPTH_COMPONENT16, kSize, kSize);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER,
                              dsRenderbufferMS);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // First renderpass: draw with depth value 0.5f
    glViewport(0, 0, kSize, kSize);
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_ALWAYS);
    glDepthMask(GL_TRUE);
    glClearColor(0.0, 0.0, 0.0, 1.0);
    glClear(GL_COLOR_BUFFER_BIT);
    glEnable(GL_BLEND);
    glBlendFunc(GL_ONE, GL_ZERO);
    ANGLE_GL_PROGRAM(drawBlue, essl1_shaders::vs::Simple(), essl1_shaders::fs::Blue());
    drawQuad(drawBlue, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();
    // The color check should end the renderpass
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::blue);

    // Create another FBO and render, jus so try to clear rendering cache. At least on pixel4,
    // the test now properly fail if I force the loadOP to DontCare in the next renderpass.
    constexpr bool clearRenderingCacheWithFBO = true;
    if (clearRenderingCacheWithFBO)
    {
        GLFramebuffer fboMS2;
        glBindFramebuffer(GL_FRAMEBUFFER, fboMS2);
        GLTexture textureMS2;
        GLRenderbuffer renderbufferMS2;
        createAndAttachColorAttachment(true, 2048, GL_COLOR_ATTACHMENT0, nullptr, mTestSampleCount,
                                       &textureMS2, &renderbufferMS2);
        GLTexture dsTextureMS2;
        GLRenderbuffer dsRenderbufferMS2;
        glBindRenderbuffer(GL_RENDERBUFFER, dsRenderbufferMS2);
        glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_DEPTH_COMPONENT16, 2048, 2048);
        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER,
                                  dsRenderbufferMS2);
        EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);
        ASSERT_GL_NO_ERROR();
        glViewport(0, 0, 2048, 2048);
        ANGLE_GL_PROGRAM(drawColor, essl1_shaders::vs::Simple(), essl1_shaders::fs::UniformColor());
        glUseProgram(drawColor);
        GLint colorUniformLocation =
            glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
        ASSERT_NE(colorUniformLocation, -1);
        glUniform4f(colorUniformLocation, 0.0f, 0.0f, 0.0f, 0.0f);
        drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
        ASSERT_GL_NO_ERROR();
    }

    // Second renderpass: Start with depth read only and then switch to depth write
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);
    glViewport(0, 0, kSize, kSize);
    glDepthFunc(GL_LESS);
    // Draw red with depth read only. pass depth test, Result: color=Red, depth=0.5
    glDepthMask(GL_FALSE);
    glBlendFunc(GL_ONE, GL_ONE);
    ANGLE_GL_PROGRAM(drawRed, essl1_shaders::vs::Simple(), essl1_shaders::fs::Red());
    glUseProgram(drawRed);
    drawQuad(drawRed, essl1_shaders::PositionAttrib(), 0.1f);
    ASSERT_GL_NO_ERROR();

    // Draw green with depth write. Pass depth test. Result: color=Green, depth=0.3
    glDepthMask(GL_TRUE);
    glBlendFunc(GL_ONE, GL_ONE);
    ANGLE_GL_PROGRAM(drawGreen, essl1_shaders::vs::Simple(), essl1_shaders::fs::Green());
    glUseProgram(drawGreen);
    drawQuad(drawGreen, essl1_shaders::PositionAttrib(), 0.3f);
    ASSERT_GL_NO_ERROR();

    // Create a texture and copy into it.
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 0, 0, kSize, kSize, 0);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    ASSERT_GL_NO_ERROR();

    // Verify the color has all three color in it.
    EXPECT_PIXEL_COLOR_EQ(1, 1, GLColor::white);
}

void MSRTTES3Test::colorAttachment1Common(bool useRenderbuffer)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture2"));
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_draw_buffers"));

    constexpr GLsizei kSize = 64;

    setupCopyTexProgram();

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    // Create multisampled framebuffer to draw into, use color attachment 1
    GLTexture textureMS;
    GLRenderbuffer renderbufferMS;
    createAndAttachColorAttachment(useRenderbuffer, kSize, GL_COLOR_ATTACHMENT1, nullptr,
                                   mTestSampleCount, &textureMS, &renderbufferMS);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Setup program to render into attachment 1.
    constexpr bool kBuffersEnabled[8] = {false, true};

    GLuint drawColor;
    setupUniformColorProgramMultiRenderTarget(kBuffersEnabled, &drawColor);
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);

    constexpr GLenum kDrawBuffers[] = {GL_NONE, GL_COLOR_ATTACHMENT1};
    glDrawBuffers(2, kDrawBuffers);
    glReadBuffer(GL_COLOR_ATTACHMENT1);
    ASSERT_GL_NO_ERROR();

    // Draw red into the multisampled color buffer.
    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Create a texture and copy into it.
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 0, 0, kSize, kSize, 0);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    ASSERT_GL_NO_ERROR();

    // Blend half-transparent green into the multisampled color buffer.
    glUniform4f(colorUniformLocation, 0.0f, 1.0f, 0.0f, 0.5f);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Verify that the texture is now yellow
    const GLColor kExpected(127, 127, 0, 191);
    EXPECT_PIXEL_COLOR_NEAR(0, 0, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, 0, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(0, kSize - 1, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, kSize - 1, kExpected, 1);

    // For completeness, verify that the texture used as copy target is red.
    verifyResults(texture, GLColor::red, kSize, 0, 0, kSize, kSize);

    ASSERT_GL_NO_ERROR();

    glDeleteProgram(drawColor);
}

// Draw, copy, then blend.  The copy will make sure an implicit resolve happens.  Regardless, the
// following draw should retain the data written by the first draw command.
// Uses color attachment 1.
TEST_P(MSRTTES3Test, ColorAttachment1)
{
    colorAttachment1Common(false);
}

// Draw, copy, then blend.  The copy will make sure an implicit resolve happens.  Regardless, the
// following draw should retain the data written by the first draw command.
// Uses color attachment 1.  Uses renderbuffer.
TEST_P(MSRTTES3Test, RenderbufferColorAttachment1)
{
    colorAttachment1Common(true);
}

void MSRTTES3Test::colorAttachments0And3Common(bool useRenderbuffer)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    ANGLE_SKIP_TEST_IF(!useRenderbuffer &&
                       !EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture2"));
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_draw_buffers"));

    constexpr GLsizei kSize = 64;

    setupCopyTexProgram();

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    // Create multisampled framebuffer to draw into, use color attachment 1
    GLTexture textureMS0;
    GLRenderbuffer renderbufferMS0;
    createAndAttachColorAttachment(useRenderbuffer, kSize, GL_COLOR_ATTACHMENT0, nullptr,
                                   mTestSampleCount, &textureMS0, &renderbufferMS0);

    GLTexture textureMS3;
    GLRenderbuffer renderbufferMS3;
    createAndAttachColorAttachment(useRenderbuffer, kSize, GL_COLOR_ATTACHMENT3, nullptr,
                                   mTestSampleCount, &textureMS3, &renderbufferMS3);

    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Setup program to render into attachments 0 and 3.
    constexpr bool kBuffersEnabled[8] = {true, false, false, true};

    GLuint drawColor;
    setupUniformColorProgramMultiRenderTarget(kBuffersEnabled, &drawColor);
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);

    constexpr GLenum kDrawBuffers[] = {GL_COLOR_ATTACHMENT0, GL_NONE, GL_NONE,
                                       GL_COLOR_ATTACHMENT3};
    glDrawBuffers(4, kDrawBuffers);
    glReadBuffer(GL_COLOR_ATTACHMENT3);
    ASSERT_GL_NO_ERROR();

    // Draw red into the multisampled color buffers.
    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Create a texture and copy from one of them.
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 0, 0, kSize, kSize, 0);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    ASSERT_GL_NO_ERROR();

    // Blend half-transparent green into the multisampled color buffers.
    glUniform4f(colorUniformLocation, 0.0f, 1.0f, 0.0f, 0.5f);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Verify that the textures are now yellow
    const GLColor kExpected(127, 127, 0, 191);
    EXPECT_PIXEL_COLOR_NEAR(0, 0, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, 0, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(0, kSize - 1, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, kSize - 1, kExpected, 1);

    glReadBuffer(GL_COLOR_ATTACHMENT0);
    EXPECT_PIXEL_COLOR_NEAR(0, 0, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, 0, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(0, kSize - 1, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, kSize - 1, kExpected, 1);
    ASSERT_GL_NO_ERROR();

    // Test color unresolve with these attachments too, by adding blue into the attachments.
    glBlendFunc(GL_ONE, GL_ONE);
    glUniform4f(colorUniformLocation, 0.0f, 0.0f, 1.0f, 0.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);

    const GLColor kExpected2(127, 127, 255, 191);

    glReadBuffer(GL_COLOR_ATTACHMENT0);
    EXPECT_PIXEL_COLOR_NEAR(0, 0, kExpected2, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, 0, kExpected2, 1);
    EXPECT_PIXEL_COLOR_NEAR(0, kSize - 1, kExpected2, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, kSize - 1, kExpected2, 1);

    glReadBuffer(GL_COLOR_ATTACHMENT3);
    EXPECT_PIXEL_COLOR_NEAR(0, 0, kExpected2, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, 0, kExpected2, 1);
    EXPECT_PIXEL_COLOR_NEAR(0, kSize - 1, kExpected2, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, kSize - 1, kExpected2, 1);

    // For completeness, verify that the texture used as copy target is red.
    verifyResults(texture, GLColor::red, kSize, 0, 0, kSize, kSize);

    ASSERT_GL_NO_ERROR();

    glDeleteProgram(drawColor);
}

// Draw, copy, then blend.  The copy will make sure an implicit resolve happens.  Regardless, the
// following draw should retain the data written by the first draw command.
// Uses color attachments 0 and 3.
TEST_P(MSRTTES3Test, ColorAttachments0And3)
{
    colorAttachments0And3Common(false);
}

// Draw, copy, then blend.  The copy will make sure an implicit resolve happens.  Regardless, the
// following draw should retain the data written by the first draw command.
// Uses color attachments 0 and 3.  Uses renderbuffer.
TEST_P(MSRTTES3Test, RenderbufferColorAttachments0And3)
{
    colorAttachments0And3Common(true);
}

// Draw with depth buffer.  Uses EXT_multisampled_render_to_texture2.
// The test works with a 64x1 texture.  The first draw call will render geometry whose depth is
// different between top and bottom.  The second draw call will enable depth test and draw with the
// average of the two depths.  Only half of the samples will take the new color.  Once resolved, the
// expected color would be the average of the two draw colors.
TEST_P(MSRTTES3Test, DepthStencilAttachment)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture2"));

    constexpr GLsizei kWidth = 64;

    // Create multisampled framebuffer to draw into, with both color and depth attachments.
    GLTexture colorMS;
    glBindTexture(GL_TEXTURE_2D, colorMS);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kWidth, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

    GLTexture depthMS;
    glBindTexture(GL_TEXTURE_2D, depthMS);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH24_STENCIL8, kWidth, 1, 0, GL_DEPTH_STENCIL,
                 GL_UNSIGNED_INT_24_8_OES, nullptr);

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         colorMS, 0, 4);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_TEXTURE_2D,
                                         depthMS, 0, 4);
    ASSERT_GL_NO_ERROR();

    // Setup draw program
    ANGLE_GL_PROGRAM(drawColor, essl1_shaders::vs::Simple(), essl1_shaders::fs::UniformColor());
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);
    GLint positionLocation = glGetAttribLocation(drawColor, essl1_shaders::PositionAttrib());
    ASSERT_NE(-1, positionLocation);

    // Setup vertices such that depth is varied from top to bottom.
    std::array<Vector3, 6> quadVertices = {
        Vector3(-1.0f, 1.0f, 0.8f), Vector3(-1.0f, -1.0f, 0.2f), Vector3(1.0f, -1.0f, 0.2f),
        Vector3(-1.0f, 1.0f, 0.8f), Vector3(1.0f, -1.0f, 0.2f),  Vector3(1.0f, 1.0f, 0.8f),
    };
    GLBuffer quadVertexBuffer;
    glBindBuffer(GL_ARRAY_BUFFER, quadVertexBuffer);
    glBufferData(GL_ARRAY_BUFFER, sizeof(GLfloat) * 3 * 6, quadVertices.data(), GL_STATIC_DRAW);
    glVertexAttribPointer(positionLocation, 3, GL_FLOAT, GL_FALSE, 0, 0);
    glEnableVertexAttribArray(positionLocation);

    // Draw red into the framebuffer.
    glViewport(0, 0, kWidth, 1);
    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_ALWAYS);
    glDrawArrays(GL_TRIANGLES, 0, 6);
    ASSERT_GL_NO_ERROR();

    // Draw green such that half the samples of each pixel pass the depth test.
    glUniform4f(colorUniformLocation, 0.0f, 1.0f, 0.0f, 1.0f);
    glDepthFunc(GL_GREATER);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    const GLColor kExpected(127, 127, 0, 255);
    EXPECT_PIXEL_COLOR_NEAR(0, 0, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(kWidth - 1, 0, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(kWidth / 2, 0, kExpected, 1);

    glDisableVertexAttribArray(0);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
}

// Draw with depth buffer, with depth discard before the end of the render
// pass. On desktop Windows AMD drivers, this would previously cause a crash
// because of a NULL pDepthStencilResolveAttachment pointer when ending the
// render pass. Other vendors don't seem to mind the NULL pointer.
TEST_P(MSRTTES3Test, DepthStencilInvalidate)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    constexpr GLsizei kWidth = 64;

    // Create multisampled framebuffer to draw into, with both color and depth attachments.
    GLTexture colorMS;
    glBindTexture(GL_TEXTURE_2D, colorMS);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kWidth, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

    GLRenderbuffer depthMS;
    glBindRenderbuffer(GL_RENDERBUFFER, depthMS);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_DEPTH_COMPONENT32F, kWidth, 1);

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         colorMS, 0, 4);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthMS);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);
    ASSERT_GL_NO_ERROR();

    // Setup draw program
    ANGLE_GL_PROGRAM(drawColor, essl1_shaders::vs::Simple(), essl1_shaders::fs::UniformColor());
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);
    GLint positionLocation = glGetAttribLocation(drawColor, essl1_shaders::PositionAttrib());
    ASSERT_NE(-1, positionLocation);

    // Setup vertices such that depth is varied from top to bottom.
    std::array<Vector3, 6> redQuadVertices = {
        Vector3(-1.0f, 1.0f, 0.8f), Vector3(-1.0f, -1.0f, 0.2f), Vector3(1.0f, -1.0f, 0.2f),
        Vector3(-1.0f, 1.0f, 0.8f), Vector3(1.0f, -1.0f, 0.2f),  Vector3(1.0f, 1.0f, 0.8f),
    };
    GLBuffer redQuadVertexBuffer;
    glBindBuffer(GL_ARRAY_BUFFER, redQuadVertexBuffer);
    glBufferData(GL_ARRAY_BUFFER, sizeof(GLfloat) * 3 * 6, redQuadVertices.data(), GL_STATIC_DRAW);
    glEnableVertexAttribArray(positionLocation);

    // Green quad has the same depth.
    std::array<Vector3, 6> greenQuadVertices = {
        Vector3(-1.0f, 1.0f, 0.5f), Vector3(-1.0f, -1.0f, 0.5f), Vector3(1.0f, -1.0f, 0.5f),
        Vector3(-1.0f, 1.0f, 0.5f), Vector3(1.0f, -1.0f, 0.5f),  Vector3(1.0f, 1.0f, 0.5f),
    };
    GLBuffer greenQuadVertexBuffer;
    glBindBuffer(GL_ARRAY_BUFFER, greenQuadVertexBuffer);
    glBufferData(GL_ARRAY_BUFFER, sizeof(GLfloat) * 3 * 6, greenQuadVertices.data(),
                 GL_STATIC_DRAW);

    // Draw red into the framebuffer.
    glViewport(0, 0, kWidth, 1);
    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_ALWAYS);
    glBindBuffer(GL_ARRAY_BUFFER, redQuadVertexBuffer);
    glVertexAttribPointer(positionLocation, 3, GL_FLOAT, GL_FALSE, 0, 0);
    glDrawArrays(GL_TRIANGLES, 0, 6);
    ASSERT_GL_NO_ERROR();

    // Draw green such that half the samples of each pixel pass the depth test.
    // Note: We don't use drawQuad() because it could internally create a vertex buffer
    // or client array pointer on the fly. Those could break the render pass in some backends and
    // force unresolve unwantedly. The unexpected unresolve would have written average depth value
    // to all samples in the depth buffer.
    glUniform4f(colorUniformLocation, 0.0f, 1.0f, 0.0f, 1.0f);
    glDepthFunc(GL_GREATER);
    glBindBuffer(GL_ARRAY_BUFFER, greenQuadVertexBuffer);
    glVertexAttribPointer(positionLocation, 3, GL_FLOAT, GL_FALSE, 0, 0);
    glDrawArrays(GL_TRIANGLES, 0, 6);
    ASSERT_GL_NO_ERROR();

    // Invalidate depth attachment
    GLenum discardDepth[] = {GL_DEPTH_ATTACHMENT};
    glInvalidateFramebuffer(GL_DRAW_FRAMEBUFFER, 1, discardDepth);

    // End render pass with pixel reads, ensure no crash occurs here.
    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
    glBindFramebuffer(GL_READ_FRAMEBUFFER, fboMS);

    const GLColor kExpected(127, 127, 0, 255);
    EXPECT_PIXEL_COLOR_NEAR(0, 0, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(kWidth - 1, 0, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(kWidth / 2, 0, kExpected, 1);

    glDisableVertexAttribArray(0);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
}

// Draw, copy, then blend. The copy triggers an implicit resolve from the multisampled
// render-to-texture attachment. This test verifies that blending after a copy preserves the
// previously written data. Uses color attachments 0 and 1, both configured as multisampled
// render-to-texture (MSRTT) attachments.
TEST_P(MSRTTES31Test, DrawCopyThenBlendWithMultipleMSRTTAttachments)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture2"));
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_draw_buffers"));

    constexpr GLsizei kSize = 64;

    setupCopyTexProgram();

    // Create multisampled framebuffer to draw into, both attachments use MSRTT
    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    GLTexture colorMS0;
    GLRenderbuffer renderbufferMS0;
    createAndAttachColorAttachment(false, kSize, GL_COLOR_ATTACHMENT0, nullptr, 4, &colorMS0,
                                   &renderbufferMS0);

    GLTexture colorMS1;
    GLRenderbuffer renderbufferMS1;
    createAndAttachColorAttachment(false, kSize, GL_COLOR_ATTACHMENT1, nullptr, 4, &colorMS1,
                                   &renderbufferMS1);

    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Setup program to render into attachments 0 and 1.
    constexpr bool kBuffersEnabled[8] = {true, true};

    GLuint drawColor;
    setupUniformColorProgramMultiRenderTarget(kBuffersEnabled, &drawColor);
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);

    constexpr GLenum kDrawBuffers[] = {GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1};
    glDrawBuffers(2, kDrawBuffers);
    glReadBuffer(GL_COLOR_ATTACHMENT1);
    ASSERT_GL_NO_ERROR();

    // Draw red into the multisampled color buffers.
    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Create a texture and copy from one of them.
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 0, 0, kSize, kSize, 0);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    ASSERT_GL_NO_ERROR();

    // Blend half-transparent green into the multisampled color buffers.
    glUniform4f(colorUniformLocation, 0.0f, 1.0f, 0.0f, 0.5f);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Verify that the textures are now yellow
    const GLColor kExpected(127, 127, 0, 191);
    EXPECT_PIXEL_COLOR_NEAR(0, 0, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, 0, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(0, kSize - 1, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, kSize - 1, kExpected, 1);

    // For completeness, verify that the texture used as copy target is red.
    verifyResults(texture, GLColor::red, kSize, 0, 0, kSize, kSize);

    ASSERT_GL_NO_ERROR();

    glDeleteProgram(drawColor);
}

// Checking for framebuffer completeness mixing regular/MSRTT multisampled renderbuffers.
TEST_P(MSRTTES3Test, FramebufferCompletenessMixedMultisamplingMode)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    typedef struct AttachmentCombination
    {
        uint32_t attach1;     // MultisamplingMode of the first surface:
                              // 0 == Regular; 1 == MultisampledRenderToTexture
        uint32_t attach2;     // MultisamplingMode of the second surface:
                              // 0 == Regular; 1 == MultisampledRenderToTexture
        GLenum attach1Point;  // The attachment point of the first surface
        GLenum attach2Point;  // The attachment point of the second surface
    } AttachmentCombination;

    constexpr std::array<AttachmentCombination, 4> attachmentCombinations = {{
        // INVALID combinations
        {0, 1, GL_COLOR_ATTACHMENT0,
         GL_DEPTH_ATTACHMENT},  // first = Regular; second = MultisampledRenderToTexture
        {0, 1, GL_COLOR_ATTACHMENT0,
         GL_STENCIL_ATTACHMENT},  // first = Regular; second = MultisampledRenderToTexture
        {1, 0, GL_COLOR_ATTACHMENT0,
         GL_DEPTH_ATTACHMENT},  // first = MultisampledRenderToTexture; second = Regular
        {1, 0, GL_COLOR_ATTACHMENT0,
         GL_STENCIL_ATTACHMENT},  // first = MultisampledRenderToTexture; second = Regular
    }};

    for (const AttachmentCombination &combination : attachmentCombinations)
    {
        GLsizei samples = 0;
        glGetIntegerv(GL_MAX_SAMPLES, &samples);

        // Texture attachment for color attachment 0.  Framebuffer should be complete.
        GLFramebuffer FBO;
        glBindFramebuffer(GL_FRAMEBUFFER, FBO);

        GLRenderbuffer colorRenderbuffer;
        glBindRenderbuffer(GL_RENDERBUFFER, colorRenderbuffer);
        if (combination.attach1 == 0)
        {
            // Regular multisampling
            glRenderbufferStorageMultisample(GL_RENDERBUFFER, samples, GL_RGBA4, 64, 64);
        }
        else
        {
            // Multisampled render to texture
            glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, samples, GL_RGBA4, 64, 64);
        }
        ASSERT_GL_NO_ERROR();
        glFramebufferRenderbuffer(GL_FRAMEBUFFER, combination.attach1Point, GL_RENDERBUFFER,
                                  colorRenderbuffer);
        EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

        // Depth/stencil renderbuffer, potentially with a different sample count.
        GLRenderbuffer dsRenderbuffer;
        glBindRenderbuffer(GL_RENDERBUFFER, dsRenderbuffer);
        if (combination.attach2 == 0)
        {
            // Regular multisampling mode
            if (combination.attach2Point == GL_DEPTH_ATTACHMENT)
            {
                // GL_DEPTH_ATTACHMENT
                glRenderbufferStorageMultisample(GL_RENDERBUFFER, samples, GL_DEPTH_COMPONENT16, 64,
                                                 64);
            }
            else
            {
                // GL_STENCIL_ATTACHMENT
                glRenderbufferStorageMultisample(GL_RENDERBUFFER, samples, GL_DEPTH24_STENCIL8, 64,
                                                 64);
            }
        }
        else
        {
            // Multisampled render to texture mode
            if (combination.attach2Point == GL_DEPTH_ATTACHMENT)
            {
                // GL_DEPTH_ATTACHMENT
                glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, samples, GL_DEPTH_COMPONENT16,
                                                    64, 64);
            }
            else
            {
                // GL_STENCIL_ATTACHMENT
                glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, samples, GL_DEPTH24_STENCIL8,
                                                    64, 64);
            }
        }
        ASSERT_GL_NO_ERROR();
        glFramebufferRenderbuffer(GL_FRAMEBUFFER, combination.attach2Point, GL_RENDERBUFFER,
                                  dsRenderbuffer);
        EXPECT_GLENUM_EQ(GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE,
                         glCheckFramebufferStatus(GL_FRAMEBUFFER));
    }
}

void MSRTTES31Test::blitFramebufferAttachment1Common(bool useRenderbuffer)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    ANGLE_SKIP_TEST_IF(!useRenderbuffer &&
                       !EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture2"));
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_draw_buffers"));

    constexpr GLsizei kSize = 16;

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    // Create multisampled framebuffer to draw into, use MSRTT for both attachments
    GLTexture textureMS0;
    GLRenderbuffer renderbufferMS0;
    createAndAttachColorAttachment(useRenderbuffer, kSize, GL_COLOR_ATTACHMENT0, nullptr,
                                   mTestSampleCount, &textureMS0, &renderbufferMS0);

    GLTexture textureMS1;
    GLRenderbuffer renderbufferMS1;
    createAndAttachColorAttachment(useRenderbuffer, kSize, GL_COLOR_ATTACHMENT1, nullptr,
                                   mTestSampleCount, &textureMS1, &renderbufferMS1);

    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Setup program to render into attachments 0 and 1.
    constexpr bool kBuffersEnabled[8] = {true, true};

    GLuint drawColor;
    setupUniformColorProgramMultiRenderTarget(kBuffersEnabled, &drawColor);
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);

    constexpr GLenum kDrawBuffers[] = {GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1};
    glDrawBuffers(2, kDrawBuffers);
    glReadBuffer(GL_COLOR_ATTACHMENT1);
    ASSERT_GL_NO_ERROR();

    // Draw red into the multisampled color buffers.
    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Create single sampled framebuffer to use as dest.
    GLFramebuffer fboSS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboSS);
    GLTexture colorSS;
    glBindTexture(GL_TEXTURE_2D, colorSS);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, colorSS, 0);
    ASSERT_GL_NO_ERROR();

    // Bind MS to READ as SS is already bound to DRAW.
    glBindFramebuffer(GL_READ_FRAMEBUFFER, fboMS);
    glReadBuffer(GL_COLOR_ATTACHMENT1);
    glBlitFramebuffer(0, 0, kSize, kSize, 0, 0, kSize, kSize, GL_COLOR_BUFFER_BIT, GL_NEAREST);
    ASSERT_GL_NO_ERROR();

    // Bind SS to READ so we can readPixels from it
    glBindFramebuffer(GL_FRAMEBUFFER, fboSS);

    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(0, kSize - 1, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, kSize - 1, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kSize / 2, kSize / 2, GLColor::red);
    ASSERT_GL_NO_ERROR();
}

// BlitFramebuffer functionality test with two MSRTT texture attachments.
// Verifies that blitting from attachment 1 works correctly and implicit resolve is triggered.
// Uses EXT_multisampled_render_to_texture2.
TEST_P(MSRTTES31Test, BlitFramebufferAttachment1)
{
    blitFramebufferAttachment1Common(false);
}

// BlitFramebuffer functionality test with two MSRTT renderbuffer attachments.
// Verifies that blitting from attachment 1 works correctly and implicit resolve is triggered.
// Uses renderbuffer.
TEST_P(MSRTTES31Test, RenderbufferBlitFramebufferAttachment1)
{
    blitFramebufferAttachment1Common(true);
}

void MSRTTES3Test::blitFramebufferMixedColorAndDepthCommon(bool useRenderbuffer)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    constexpr GLsizei kSize = 16;

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    // Create multisampled framebuffer to use as source.
    GLRenderbuffer depthMS;
    glBindRenderbuffer(GL_RENDERBUFFER, depthMS);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_DEPTH_COMPONENT24, kSize, kSize);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthMS);

    GLTexture textureMS;
    GLRenderbuffer renderbufferMS;
    createAndAttachColorAttachment(useRenderbuffer, kSize, GL_COLOR_ATTACHMENT0, nullptr,
                                   mTestSampleCount, &textureMS, &renderbufferMS);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Clear depth to 0.5 and color to red.
    glClearDepthf(0.5f);
    glClearColor(1.0f, 0.0f, 0.0f, 1.0f);
    glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
    ASSERT_GL_NO_ERROR();

    // Create single sampled framebuffer to use as dest.
    GLRenderbuffer depthSS;
    glBindRenderbuffer(GL_RENDERBUFFER, depthSS);
    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24, kSize, kSize);

    GLTexture colorSS;
    glBindTexture(GL_TEXTURE_2D, colorSS);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

    GLFramebuffer fboSS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboSS);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthSS);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, colorSS, 0);
    ASSERT_GL_NO_ERROR();

    // Bind MS to READ as SS is already bound to DRAW.
    glBindFramebuffer(GL_READ_FRAMEBUFFER, fboMS);
    glBlitFramebuffer(0, 0, kSize, kSize, 0, 0, kSize, kSize,
                      GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT, GL_NEAREST);
    ASSERT_GL_NO_ERROR();

    // Bind SS to READ so we can readPixels from it
    glBindFramebuffer(GL_FRAMEBUFFER, fboSS);

    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(0, kSize - 1, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, kSize - 1, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kSize / 2, kSize / 2, GLColor::red);
    ASSERT_GL_NO_ERROR();

    // Use a small shader to verify depth.
    ANGLE_GL_PROGRAM(depthTestProgram, essl1_shaders::vs::Passthrough(), essl1_shaders::fs::Blue());
    ANGLE_GL_PROGRAM(depthTestProgramFail, essl1_shaders::vs::Passthrough(),
                     essl1_shaders::fs::Green());
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_LESS);
    drawQuad(depthTestProgram, essl1_shaders::PositionAttrib(), -0.01f);
    drawQuad(depthTestProgramFail, essl1_shaders::PositionAttrib(), 0.01f);
    glDisable(GL_DEPTH_TEST);
    ASSERT_GL_NO_ERROR();

    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, 0, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(0, kSize - 1, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, kSize - 1, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(kSize / 2, kSize / 2, GLColor::blue);
    ASSERT_GL_NO_ERROR();
}

// BlitFramebuffer functionality test with mixed multisampled-render-to-texture color attachment and
// multisampled depth buffer.  This test makes sure that the color attachment is blitted, while
// the depth/stencil attachment is resolved.
TEST_P(MSRTTES3Test, BlitFramebufferMixedColorAndDepth)
{
    blitFramebufferMixedColorAndDepthCommon(false);
}

// BlitFramebuffer functionality test with mixed multisampled-render-to-texture color attachment and
// multisampled depth buffer.  This test makes sure that the color attachment is blitted, while
// the depth/stencil attachment is resolved.  Uses renderbuffer.
TEST_P(MSRTTES3Test, RenderbufferBlitFramebufferMixedColorAndDepth)
{
    blitFramebufferMixedColorAndDepthCommon(true);
}

// Draw non-multisampled, draw multisampled, repeat.  This tests the same texture being bound
// differently to two FBOs.
TEST_P(MSRTTTest, DrawNonMultisampledThenMultisampled)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    constexpr GLsizei kSize = 64;

    // Texture attachment to the two framebuffers.
    GLTexture color;
    glBindTexture(GL_TEXTURE_2D, color);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

    // Create singlesampled framebuffer.
    GLFramebuffer fboSS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboSS);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, color, 0);
    ASSERT_GL_NO_ERROR();

    // Create multisampled framebuffer.
    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, color,
                                         0, 4);
    ASSERT_GL_NO_ERROR();

    // Draw red into the multisampled color buffer.
    ANGLE_GL_PROGRAM(drawColor, essl1_shaders::vs::Simple(), essl1_shaders::fs::UniformColor());
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);

    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Draw green into the singlesampled color buffer
    glBindFramebuffer(GL_FRAMEBUFFER, fboSS);
    glEnable(GL_SCISSOR_TEST);
    glScissor(kSize / 8, kSize / 8, 3 * kSize / 4, 3 * kSize / 4);
    glUniform4f(colorUniformLocation, 0.0f, 1.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Draw blue into the multisampled color buffer
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);
    glScissor(kSize / 4, kSize / 4, kSize / 2, kSize / 2);
    glUniform4f(colorUniformLocation, 0.0f, 0.0f, 1.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Verify that the texture is red on the border, blue in the middle and green in between.
    glBindFramebuffer(GL_READ_FRAMEBUFFER, fboSS);

    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(0, kSize - 1, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, kSize - 1, GLColor::red);

    EXPECT_PIXEL_COLOR_EQ(3 * kSize / 16, 3 * kSize / 16, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(13 * kSize / 16, 3 * kSize / 16, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(3 * kSize / 16, 13 * kSize / 16, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(13 * kSize / 16, 13 * kSize / 16, GLColor::green);

    EXPECT_PIXEL_COLOR_EQ(3 * kSize / 8, 3 * kSize / 8, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(5 * kSize / 8, 3 * kSize / 8, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(3 * kSize / 8, 5 * kSize / 8, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(5 * kSize / 8, 5 * kSize / 8, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(kSize / 2, kSize / 2, GLColor::blue);

    ASSERT_GL_NO_ERROR();
}

// Draw multisampled triangle with different sample counts on one single FBO. This test makes use of
// different sample results for different sample location to distinguish whether sample count truly
// changed or not.
TEST_P(MSRTTTest, DrawMultisampledDifferentSamplesOneFBO)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    constexpr GLsizei kSize = 64;

    GLsizei maxSamples = 0;
    glGetIntegerv(GL_MAX_SAMPLES, &maxSamples);
    ANGLE_SKIP_TEST_IF(maxSamples <= 4);

    GLTexture color;
    glBindTexture(GL_TEXTURE_2D, color);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    std::array<GLfloat, 16> attribPosData = {1, 1,  0.5, 1, -1, 1,  0.5, 1,
                                             1, -1, 0.5, 1, -1, -1, 0.5, 1};
    const uint16_t indices[]              = {0, 1, 2};

    // Refer to Vulkan spec Standard Sample Locations
    const GLColor kExpected4(128, 0, 0, 255);
    const GLColor kExpected8(159, 0, 0, 255);

    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);

    ANGLE_GL_PROGRAM(drawColorTriangle, essl1_shaders::vs::Simple(),
                     essl1_shaders::fs::UniformColor());
    glUseProgram(drawColorTriangle);

    GLint colorUniformLocation =
        glGetUniformLocation(drawColorTriangle, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);
    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);

    GLint positionUniformLocation =
        glGetAttribLocation(drawColorTriangle, angle::essl1_shaders::PositionAttrib());
    ASSERT_NE(positionUniformLocation, -1);
    glEnableVertexAttribArray(positionUniformLocation);
    glVertexAttribPointer(positionUniformLocation, 4, GL_FLOAT, GL_FALSE, 0, attribPosData.data());

    // First set sample count to 4.
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, color,
                                         0, 4);
    glClear(GL_COLOR_BUFFER_BIT);

    glDrawElements(GL_TRIANGLES, 3, GL_UNSIGNED_SHORT, indices);
    EXPECT_PIXEL_COLOR_NEAR(kSize / 2 - 1, kSize / 2, kExpected4, 1);

    // Then set sample count to 8 without changing FBO.
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, color,
                                         0, 8);
    glClear(GL_COLOR_BUFFER_BIT);

    glDrawElements(GL_TRIANGLES, 3, GL_UNSIGNED_SHORT, indices);
    EXPECT_PIXEL_COLOR_NEAR(kSize / 2 - 1, kSize / 2, kExpected8, 1);

    ASSERT_GL_NO_ERROR();
}

// Draw multisampled, draw multisampled with another sample count, repeat.  This tests the same
// texture being bound as multisampled-render-to-texture with different sample counts to two FBOs.
TEST_P(MSRTTTest, DrawMultisampledDifferentSamples)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    constexpr GLsizei kSize = 64;

    GLsizei maxSamples = 0;
    glGetIntegerv(GL_MAX_SAMPLES, &maxSamples);
    ASSERT_GE(maxSamples, 4);

    // Texture attachment to the two framebuffers.
    GLTexture color;
    glBindTexture(GL_TEXTURE_2D, color);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

    // Create two multisampled framebuffers.
    GLFramebuffer fboMS1;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS1);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, color,
                                         0, 4);

    GLFramebuffer fboMS2;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS2);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, color,
                                         0, maxSamples);
    ASSERT_GL_NO_ERROR();

    // Draw red into the first multisampled color buffer.
    ANGLE_GL_PROGRAM(drawColor, essl1_shaders::vs::Simple(), essl1_shaders::fs::UniformColor());
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);

    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Draw green into the second multisampled color buffer
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS1);
    glEnable(GL_SCISSOR_TEST);
    glScissor(kSize / 8, kSize / 8, 3 * kSize / 4, 3 * kSize / 4);
    glUniform4f(colorUniformLocation, 0.0f, 1.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Draw blue into the first multisampled color buffer
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS2);
    glScissor(kSize / 4, kSize / 4, kSize / 2, kSize / 2);
    glUniform4f(colorUniformLocation, 0.0f, 0.0f, 1.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Verify that the texture is red on the border, blue in the middle and green in between.
    GLFramebuffer fboSS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboSS);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, color, 0);
    ASSERT_GL_NO_ERROR();

    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(0, kSize - 1, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(kSize - 1, kSize - 1, GLColor::red);

    EXPECT_PIXEL_COLOR_EQ(3 * kSize / 16, 3 * kSize / 16, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(13 * kSize / 16, 3 * kSize / 16, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(3 * kSize / 16, 13 * kSize / 16, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(13 * kSize / 16, 13 * kSize / 16, GLColor::green);

    EXPECT_PIXEL_COLOR_EQ(3 * kSize / 8, 3 * kSize / 8, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(5 * kSize / 8, 3 * kSize / 8, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(3 * kSize / 8, 5 * kSize / 8, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(5 * kSize / 8, 5 * kSize / 8, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(kSize / 2, kSize / 2, GLColor::blue);

    ASSERT_GL_NO_ERROR();
}

void MSRTTES31Test::drawCopyThenBlendAllAttachmentsMixed(bool useRenderbuffer)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture2"));

    GLint maxDrawBuffers = 0;
    glGetIntegerv(GL_MAX_DRAW_BUFFERS, &maxDrawBuffers);

    // At least 4 draw buffers per GLES3.0 spec.
    ASSERT_GE(maxDrawBuffers, 4);

    // Maximum 8 draw buffers exposed by ANGLE.
    constexpr GLint kImplMaxDrawBuffers = 8;
    maxDrawBuffers                      = std::min(maxDrawBuffers, kImplMaxDrawBuffers);

    // Integer formats are mixed in which have different sample count limits. A framebuffer must
    // have the same sample count for all attachments.
    const GLint sampleCount = std::min(mTestSampleCount, mMaxIntegerSamples);

    constexpr std::array<const char *, kImplMaxDrawBuffers> kDecl = {
        "layout(location = 0) out vec4 out0;",  "layout(location = 1) out ivec4 out1;",
        "layout(location = 2) out uvec4 out2;", "layout(location = 3) out vec4 out3;",
        "layout(location = 4) out uvec4 out4;", "layout(location = 5) out ivec4 out5;",
        "layout(location = 6) out ivec4 out6;", "layout(location = 7) out vec4 out7;",
    };

    constexpr std::array<GLType, kImplMaxDrawBuffers> kGLType = {{
        {GL_RGBA8, GL_RGBA, GL_UNSIGNED_BYTE},
        {GL_RGBA32I, GL_RGBA_INTEGER, GL_INT},
        {GL_RGBA32UI, GL_RGBA_INTEGER, GL_UNSIGNED_INT},
        {GL_RGBA8, GL_RGBA, GL_UNSIGNED_BYTE},
        {GL_RGBA32UI, GL_RGBA_INTEGER, GL_UNSIGNED_INT},
        {GL_RGBA32I, GL_RGBA_INTEGER, GL_INT},
        {GL_RGBA32I, GL_RGBA_INTEGER, GL_INT},
        {GL_RGBA8, GL_RGBA, GL_UNSIGNED_BYTE},
    }};

    constexpr std::array<const char *, kImplMaxDrawBuffers> kAssign1 = {
        "out0 = vec4(1.0f, 0.0f, 0.0f, 1.0f);",
        "out1 = ivec4(-19, 13, 123456, -654321);",
        "out2 = uvec4(98765, 43210, 2, 0);",
        "out3 = vec4(0.0f, 1.0f, 0.0f, 1.0f);",
        "out4 = uvec4(10101010, 2345, 0, 991);",
        "out5 = ivec4(615243, -948576, -222, 111);",
        "out6 = ivec4(-8127931, -1392781, 246810, 1214161820);",
        "out7 = vec4(0.0f, 0.0f, 1.0f, 1.0f);",
    };

    constexpr std::array<const char *, kImplMaxDrawBuffers> kAssign2 = {
        "out0 = vec4(0.0f, 1.0f, 0.0f, 0.5f);",
        "out1 = ivec4(0, 0, 0, 0);",
        "out2 = uvec4(0, 0, 0, 0);",
        "out3 = vec4(0.0f, 0.0f, 1.0f, 0.5f);",
        "out4 = uvec4(0, 0, 0, 0);",
        "out5 = ivec4(0, 0, 0, 0);",
        "out6 = ivec4(0, 0, 0, 0);",
        "out7 = vec4(1.0f, 0.0f, 0.0f, 0.5f);",
    };

    // Generate the shaders, [0] for first draw and [1] for second.
    std::array<std::stringstream, 2> fsStr;
    for (unsigned int index = 0; index < 2; ++index)
    {
        fsStr[index] << R"(#version 300 es
precision highp float;
)";

        for (GLint drawBuffer = 0; drawBuffer < maxDrawBuffers; ++drawBuffer)
        {
            fsStr[index] << kDecl[drawBuffer] << "\n";
        }

        fsStr[index] << R"(void main()
{
)";

        const auto &assign = index == 0 ? kAssign1 : kAssign2;
        for (GLint drawBuffer = 0; drawBuffer < maxDrawBuffers; ++drawBuffer)
        {
            fsStr[index] << assign[drawBuffer] << "\n";
        }

        fsStr[index] << "}\n";
    }

    constexpr GLsizei kSize = 64;

    setupCopyTexProgram();

    // Create multisampled framebuffer to draw into
    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    std::array<GLTexture, kImplMaxDrawBuffers> textureMS;
    std::array<GLRenderbuffer, kImplMaxDrawBuffers> renderbufferMS;
    for (GLint drawBuffer = 0; drawBuffer < maxDrawBuffers; ++drawBuffer)
    {
        createAndAttachColorAttachment(useRenderbuffer, kSize, GL_COLOR_ATTACHMENT0 + drawBuffer,
                                       &kGLType[drawBuffer], sampleCount, &textureMS[drawBuffer],
                                       &renderbufferMS[drawBuffer]);
    }
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Setup programs
    ANGLE_GL_PROGRAM(drawProg, essl3_shaders::vs::Simple(), fsStr[0].str().c_str());
    ANGLE_GL_PROGRAM(blendProg, essl3_shaders::vs::Simple(), fsStr[1].str().c_str());

    constexpr GLenum kDrawBuffers[] = {
        GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1, GL_COLOR_ATTACHMENT2, GL_COLOR_ATTACHMENT3,
        GL_COLOR_ATTACHMENT4, GL_COLOR_ATTACHMENT5, GL_COLOR_ATTACHMENT6, GL_COLOR_ATTACHMENT7};
    glDrawBuffers(maxDrawBuffers, kDrawBuffers);
    ASSERT_GL_NO_ERROR();

    // Draw into the multisampled color buffers.
    glUseProgram(drawProg);
    drawQuad(drawProg, essl3_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Create a texture and copy from one of them.
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 0, 0, kSize, kSize, 0);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    ASSERT_GL_NO_ERROR();

    // Blend color buffers.
    glUseProgram(blendProg);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    drawQuad(blendProg, essl3_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Verify texture colors.
    glReadBuffer(GL_COLOR_ATTACHMENT0);
    const GLColor kExpected0(127, 127, 0, 191);
    EXPECT_PIXEL_COLOR_NEAR(0, 0, kExpected0, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, 0, kExpected0, 1);
    EXPECT_PIXEL_COLOR_NEAR(0, kSize - 1, kExpected0, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, kSize - 1, kExpected0, 1);

    glReadBuffer(GL_COLOR_ATTACHMENT3);
    const GLColor kExpected3(0, 127, 127, 191);
    EXPECT_PIXEL_COLOR_NEAR(0, 0, kExpected3, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, 0, kExpected3, 1);
    EXPECT_PIXEL_COLOR_NEAR(0, kSize - 1, kExpected3, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, kSize - 1, kExpected3, 1);

    if (maxDrawBuffers > 7)
    {
        glReadBuffer(GL_COLOR_ATTACHMENT7);
        const GLColor kExpected7(127, 0, 127, 191);
        EXPECT_PIXEL_COLOR_NEAR(0, 0, kExpected7, 1);
        EXPECT_PIXEL_COLOR_NEAR(kSize - 1, 0, kExpected7, 1);
        EXPECT_PIXEL_COLOR_NEAR(0, kSize - 1, kExpected7, 1);
        EXPECT_PIXEL_COLOR_NEAR(kSize - 1, kSize - 1, kExpected7, 1);
    }

    // For completeness, verify that the texture used as copy target is red.
    verifyResults(texture, GLColor::red, kSize, 0, 0, kSize, kSize);

    ASSERT_GL_NO_ERROR();
}

// Draw, copy, then blend with 8 mixed format attachments.  The copy will make sure an implicit
// resolve happens.  Regardless, the following draw should retain the data written by the first draw
// command.
TEST_P(MSRTTES31Test, DrawCopyThenBlendAllAttachmentsMixed)
{
    drawCopyThenBlendAllAttachmentsMixed(false);
}

// Same as DrawCopyThenBlendAllAttachmentsMixed but with renderbuffers.
TEST_P(MSRTTES31Test, RenderbufferDrawCopyThenBlendAllAttachmentsMixed)
{
    // Linux Intel Vulkan returns 0 for GL_MAX_INTEGER_SAMPLES http://anglebug.com/42264519
    ANGLE_SKIP_TEST_IF(IsLinux() && IsIntel() && IsVulkan());

    drawCopyThenBlendAllAttachmentsMixed(true);
}

void MSRTTES3Test::renderbufferUnresolveColorAndDepthStencilThenTwoColors(bool withDepth,
                                                                          bool withStencil)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture2"));
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_draw_buffers"));

    // http://anglebug.com/42263663
    ANGLE_SKIP_TEST_IF(IsLinux() && IsIntel() && IsVulkan());

    constexpr GLsizei kSize = 64;

    setupCopyTexProgram();

    GLFramebuffer fboColorAndDepthStencil;
    glBindFramebuffer(GL_FRAMEBUFFER, fboColorAndDepthStencil);

    // Create framebuffer to draw into, with both color and depth/stencil attachments.
    GLTexture color1;
    glBindTexture(GL_TEXTURE_2D, color1);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         color1, 0, 4);

    GLenum depthStencilFormat = GL_DEPTH24_STENCIL8;
    GLenum depthStencilTarget = GL_DEPTH_STENCIL_ATTACHMENT;

    ASSERT_TRUE(withDepth || withStencil);
    if (withDepth && !withStencil)
    {
        depthStencilFormat = GL_DEPTH_COMPONENT24;
        depthStencilTarget = GL_DEPTH_ATTACHMENT;
    }
    if (!withDepth && withStencil)
    {
        depthStencilFormat = GL_STENCIL_INDEX8;
        depthStencilTarget = GL_STENCIL_ATTACHMENT;
    }

    GLRenderbuffer depthStencil;
    glBindRenderbuffer(GL_RENDERBUFFER, depthStencil);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, depthStencilFormat, kSize, kSize);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, depthStencilTarget, GL_RENDERBUFFER, depthStencil);
    ASSERT_GL_NO_ERROR();
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Set viewport and clear depth/stencil
    glViewport(0, 0, kSize, kSize);
    glClearDepthf(1);
    glClearStencil(0x55);
    glClear(GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);

    // If depth is not cleared to 1, rendering would fail.
    if (withDepth)
    {
        glEnable(GL_DEPTH_TEST);
        glDepthFunc(GL_LESS);
    }

    // If stencil is not cleared to 0x55, rendering would fail.
    if (withStencil)
    {
        glEnable(GL_STENCIL_TEST);
        glStencilFunc(GL_EQUAL, 0x55, 0xFF);
        glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
        glStencilMask(0xFF);
    }

    // Set up program
    ANGLE_GL_PROGRAM(drawColor, essl1_shaders::vs::Simple(), essl1_shaders::fs::UniformColor());
    glUseProgram(drawColor);
    GLint colorUniformLocation =
        glGetUniformLocation(drawColor, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocation, -1);

    // Draw red
    glUniform4f(colorUniformLocation, 1.0f, 0.0f, 0.0f, 1.0f);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.25f);
    ASSERT_GL_NO_ERROR();

    // Create a texture and copy into it.
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 0, 0, kSize, kSize, 0);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    ASSERT_GL_NO_ERROR();

    // Draw again into the framebuffer, this time blending.  This tests that both the color and
    // depth/stencil data are preserved after the resolve incurred by the copy above.
    glUniform4f(colorUniformLocation, 0.0f, 1.0f, 0.0f, 0.5f);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    drawQuad(drawColor, essl1_shaders::PositionAttrib(), 0.0f);
    ASSERT_GL_NO_ERROR();

    // Verify that the texture is now yellow
    const GLColor kExpected(127, 127, 0, 191);
    EXPECT_PIXEL_COLOR_NEAR(0, 0, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, 0, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(0, kSize - 1, kExpected, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, kSize - 1, kExpected, 1);

    // For completeness, verify that the texture used as copy target is red.
    verifyResults(texture, GLColor::red, kSize, 0, 0, kSize, kSize);

    // Now create a framebuffer with two color attachments and do something similar.  This makes
    // sure that the fact that both these framebuffers have 2 attachments does not cause confusion,
    // for example by having the unresolve shader generated for the first framebuffer used for the
    // second framebuffer.
    GLFramebuffer fboTwoColors;
    glBindFramebuffer(GL_FRAMEBUFFER, fboTwoColors);

    GLTexture color2;
    glBindTexture(GL_TEXTURE_2D, color2);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         color2, 0, 4);

    GLTexture color3;
    glBindTexture(GL_TEXTURE_2D, color3);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, GL_TEXTURE_2D,
                                         color3, 0, 4);

    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    glDisable(GL_DEPTH_TEST);
    glDisable(GL_STENCIL_TEST);
    glDisable(GL_BLEND);

    constexpr GLenum kDrawBuffers[] = {GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1};
    glDrawBuffers(2, kDrawBuffers);
    glReadBuffer(GL_COLOR_ATTACHMENT1);

    // Setup program
    constexpr bool kBuffersEnabled[8] = {true, true};

    GLuint drawColorMRT;
    setupUniformColorProgramMultiRenderTarget(kBuffersEnabled, &drawColorMRT);
    glUseProgram(drawColorMRT);
    GLint colorUniformLocationMRT =
        glGetUniformLocation(drawColorMRT, angle::essl1_shaders::ColorUniform());
    ASSERT_NE(colorUniformLocationMRT, -1);

    // Draw blue
    glUniform4f(colorUniformLocationMRT, 0.0f, 0.0f, 1.0f, 1.0f);
    drawQuad(drawColorMRT, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Copy into texture
    glBindTexture(GL_TEXTURE_2D, texture);
    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 0, 0, kSize, kSize, 0);

    // Blend.
    glUniform4f(colorUniformLocationMRT, 0.0f, 1.0f, 0.0f, 0.5f);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    drawQuad(drawColorMRT, essl1_shaders::PositionAttrib(), 0.0f);
    ASSERT_GL_NO_ERROR();

    // Verify that the texture is now cyan
    const GLColor kExpected2(0, 127, 127, 191);
    EXPECT_PIXEL_COLOR_NEAR(0, 0, kExpected2, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, 0, kExpected2, 1);
    EXPECT_PIXEL_COLOR_NEAR(0, kSize - 1, kExpected2, 1);
    EXPECT_PIXEL_COLOR_NEAR(kSize - 1, kSize - 1, kExpected2, 1);

    // For completeness, verify that the texture used as copy target is blue.
    verifyResults(texture, GLColor::blue, kSize, 0, 0, kSize, kSize);
}

// Draw, copy, then blend once on a framebuffer with color and depth attachments, and once with two
// color attachments.  Tests that unresolve is done correctly on two framebuffers with the same
// number of attachments, but differing in depth being there.  Note that this test doesn't apply to
// depth/stencil textures as they are explicitly autoinvalidated between render passes.
TEST_P(MSRTTES3Test, RenderbufferUnresolveColorAndDepthThenTwoColors)
{
    renderbufferUnresolveColorAndDepthStencilThenTwoColors(true, false);
}

// Similar to RenderbufferUnresolveColorAndDepthThenTwoColors, but with stencil.
TEST_P(MSRTTES3Test, RenderbufferUnresolveColorAndStencilThenTwoColors)
{
    renderbufferUnresolveColorAndDepthStencilThenTwoColors(false, true);
}

// Similar to RenderbufferUnresolveColorAndDepthThenTwoColors, but with depth and stencil.
TEST_P(MSRTTES3Test, RenderbufferUnresolveColorAndDepthStencilThenTwoColors)
{
    renderbufferUnresolveColorAndDepthStencilThenTwoColors(true, true);
}

// Make sure deferred clears are flushed correctly when the framebuffer switches between
// needing unresolve and not needing it.
TEST_P(MSRTTES3Test, ClearThenMaskedClearFramebufferTest)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    constexpr GLsizei kSize = 16;

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);

    // Create multisampled framebuffer to use as source.
    GLRenderbuffer depthMS;
    glBindRenderbuffer(GL_RENDERBUFFER, depthMS);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_DEPTH_COMPONENT24, kSize, kSize);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthMS);
    ASSERT_GL_NO_ERROR();

    GLTexture textureMS;
    GLRenderbuffer renderbufferMS;
    createAndAttachColorAttachment(false, kSize, GL_COLOR_ATTACHMENT0, nullptr, mTestSampleCount,
                                   &textureMS, &renderbufferMS);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Clear depth to 0.5 and color to green.
    glClearDepthf(0.5f);
    glClearColor(0.0f, 1.0f, 0.0f, 1.0f);
    glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
    ASSERT_GL_NO_ERROR();

    // Break the render pass.
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::green);

    // Draw red into the multisampled color buffer.  An unresolve operation is needed.
    ANGLE_GL_PROGRAM(drawRed, essl1_shaders::vs::Simple(), essl1_shaders::fs::Red());
    ANGLE_GL_PROGRAM(drawBlue, essl1_shaders::vs::Simple(), essl1_shaders::fs::Blue());
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_LEQUAL);
    drawQuad(drawRed, essl1_shaders::PositionAttrib(), -0.05f);
    drawQuad(drawBlue, essl1_shaders::PositionAttrib(), 0.05f);
    ASSERT_GL_NO_ERROR();

    // Break the render pass.
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::red);

    // Clear color to transparent blue.
    glClearColor(0.0f, 0.0f, 1.0f, 0.0f);
    glClear(GL_COLOR_BUFFER_BIT);

    // Clear both color and depth, with color masked.
    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    glColorMask(GL_FALSE, GL_TRUE, GL_FALSE, GL_TRUE);
    glClearDepthf(0.3f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    // Make sure the result is blue.
    EXPECT_PIXEL_RECT_EQ(0, 0, kSize - 1, kSize - 1, GLColor::blue);
    ASSERT_GL_NO_ERROR();
}

// Make sure mid render pass clear works correctly.
TEST_P(MSRTTES3Test, RenderToTextureMidRenderPassDepthClear)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    constexpr GLsizei kSize = 6;

    // Create multisampled framebuffer to draw into, with both color and depth attachments.
    GLTexture colorMS;
    glBindTexture(GL_TEXTURE_2D, colorMS);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

    GLRenderbuffer depthStencilMS;
    glBindRenderbuffer(GL_RENDERBUFFER, depthStencilMS);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_DEPTH24_STENCIL8, kSize, kSize);

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         colorMS, 0, 4);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER,
                              depthStencilMS);
    ASSERT_GL_NO_ERROR();

    // Set up texture for copy operation that breaks the render pass
    GLTexture copyTex;
    glBindTexture(GL_TEXTURE_2D, copyTex);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

    // First render pass: draw and then break the render pass so that we have initial data in the
    // depth buffer 0.75f
    glViewport(0, 0, kSize, kSize);
    glClearColor(0, 0, 0, 0.0f);
    glClearDepthf(0.0);
    glClearStencil(0x55);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_ALWAYS);
    glDepthMask(GL_TRUE);
    ANGLE_GL_PROGRAM(redProgram, essl1_shaders::vs::Simple(), essl1_shaders::fs::Red());
    // depthValue = 1/2 * 0.5f + 1/2 = 0.75f
    drawQuad(redProgram, essl1_shaders::PositionAttrib(), 0.5f);
    glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, kSize, kSize);
    ASSERT_GL_NO_ERROR();

    // Second render pass: set depth test to always pass and then draw. ANGLE may optimize to not
    // load depth value. Depth buffer should still be 0.75f with color buffer being green.
    glDepthMask(GL_FALSE);
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_ALWAYS);
    ANGLE_GL_PROGRAM(greenProgram, essl1_shaders::vs::Simple(), essl1_shaders::fs::Green());
    drawQuad(greenProgram, essl1_shaders::PositionAttrib(), 1.0f);

    // Now do mid-renderPass clear to 0.4f
    glDepthMask(GL_TRUE);
    glClearDepthf(0.4f);
    glClear(GL_DEPTH_BUFFER_BIT);

    // Draw blue with depth value 0.5f. This should pass depth test (0.5f>=0.4f) and we see blue.
    // If mid-RenderPass clear not working properly, depthBuffer should still have 0.75 and depth
    // test will fail and you see Green.
    glDepthFunc(GL_GEQUAL);
    ANGLE_GL_PROGRAM(blueProgram, essl1_shaders::vs::Simple(), essl1_shaders::fs::Blue());
    // depthValue = 1/2 * 0.0f + 1/2 = 0.5f
    drawQuad(blueProgram, essl1_shaders::PositionAttrib(), 0.0f);

    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::blue);
    ASSERT_GL_NO_ERROR();
}

// Test depth-only rendering
TEST_P(MSRTTES3Test, RenderToTextureDepthOnly)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    constexpr GLsizei kSize = 6;

    // Create multisampled framebuffer with only depth attachments.
    GLRenderbuffer depthStencilMS;
    glBindRenderbuffer(GL_RENDERBUFFER, depthStencilMS);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_DEPTH24_STENCIL8, kSize, kSize);

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthStencilMS);
    ASSERT_GL_NO_ERROR();

    // Render to depth
    glClearDepthf(0.0);
    glClear(GL_DEPTH_BUFFER_BIT);
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_ALWAYS);
    glDepthMask(GL_TRUE);
    ANGLE_GL_PROGRAM(redProgram, essl1_shaders::vs::Simple(), essl1_shaders::fs::Red());
    // depthValue = 1/2 * 0.5f + 1/2 = 0.75f
    drawQuad(redProgram, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Blit depth to verify it
    GLFramebuffer fbo;
    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, fbo);

    GLTexture color;
    glBindTexture(GL_TEXTURE_2D, color);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, color, 0);

    GLRenderbuffer depthStencil;
    glBindRenderbuffer(GL_RENDERBUFFER, depthStencil);
    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, kSize, kSize);
    glFramebufferRenderbuffer(GL_DRAW_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER,
                              depthStencil);
    ASSERT_GL_NO_ERROR();
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_DRAW_FRAMEBUFFER);

    glBlitFramebuffer(0, 0, kSize, kSize, 0, 0, kSize, kSize, GL_DEPTH_BUFFER_BIT, GL_NEAREST);

    // Verify depth
    ANGLE_GL_PROGRAM(blueProgram, essl1_shaders::vs::Simple(), essl1_shaders::fs::Blue());
    glDepthFunc(GL_LESS);
    drawQuad(redProgram, essl1_shaders::PositionAttrib(), 0.49);
    drawQuad(blueProgram, essl1_shaders::PositionAttrib(), 0.51);

    glBindFramebuffer(GL_READ_FRAMEBUFFER, fbo);
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::red);
    ASSERT_GL_NO_ERROR();
}

// Test stencil-only rendering
TEST_P(MSRTTES3Test, RenderToTextureStencilOnly)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    constexpr GLsizei kSize = 6;

    // Create multisampled framebuffer with only stencil attachments.
    GLRenderbuffer depthStencilMS;
    glBindRenderbuffer(GL_RENDERBUFFER, depthStencilMS);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_DEPTH24_STENCIL8, kSize, kSize);

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_RENDERBUFFER,
                              depthStencilMS);
    ASSERT_GL_NO_ERROR();

    // Render to stencil
    glClearStencil(0x55);
    glClear(GL_STENCIL_BUFFER_BIT);
    glEnable(GL_STENCIL_TEST);
    glStencilFunc(GL_ALWAYS, 0xA4, 0xFF);
    glStencilOp(GL_REPLACE, GL_REPLACE, GL_REPLACE);
    glStencilMask(0xFF);
    ANGLE_GL_PROGRAM(redProgram, essl1_shaders::vs::Simple(), essl1_shaders::fs::Red());
    drawQuad(redProgram, essl1_shaders::PositionAttrib(), 0.5f);
    ASSERT_GL_NO_ERROR();

    // Blit stencil to verify it
    GLFramebuffer fbo;
    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, fbo);

    GLTexture color;
    glBindTexture(GL_TEXTURE_2D, color);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, color, 0);

    GLRenderbuffer depthStencil;
    glBindRenderbuffer(GL_RENDERBUFFER, depthStencil);
    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, kSize, kSize);
    glFramebufferRenderbuffer(GL_DRAW_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_RENDERBUFFER,
                              depthStencil);
    ASSERT_GL_NO_ERROR();
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_DRAW_FRAMEBUFFER);

    glBlitFramebuffer(0, 0, kSize, kSize, 0, 0, kSize, kSize, GL_STENCIL_BUFFER_BIT, GL_NEAREST);

    // Verify stencil
    ANGLE_GL_PROGRAM(blueProgram, essl1_shaders::vs::Simple(), essl1_shaders::fs::Blue());
    glStencilFunc(GL_EQUAL, 0xA4, 0xFF);
    drawQuad(blueProgram, essl1_shaders::PositionAttrib(), 0.5);

    glBindFramebuffer(GL_READ_FRAMEBUFFER, fbo);
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::blue);
    ASSERT_GL_NO_ERROR();
}

// Test that MSRTT rendering to cubemap faces work.
TEST_P(MSRTTES3Test, CubeMap)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    constexpr char kFS[] = R"(#version 300 es
#extension GL_OES_sample_variables : enable
precision mediump float;
out vec4 color;
void main()
{
    switch (gl_SampleID % 4)
    {
    case 0:
        color = vec4(1.0, 0.9, 0.8, 0.7);
        break;
    case 1:
        color = vec4(0.0, 0.1, 0.2, 0.3);
        break;
    case 2:
        color = vec4(0.5, 0.25, 0.75, 1.0);
        break;
    case 3:
        color = vec4(0.4, 0.6, 0.2, 0.8);
        break;
    }
})";
    ANGLE_GL_PROGRAM(program, essl3_shaders::vs::Simple(), kFS);

    constexpr GLsizei kSize = 6;

    // Create multisampled framebuffer to draw into, with both color and depth attachments.
    GLTexture color;
    glBindTexture(GL_TEXTURE_CUBE_MAP, color);
    for (GLenum face = 0; face < 6; face++)
    {
        glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA,
                     GL_UNSIGNED_BYTE, nullptr);
        ASSERT_GL_NO_ERROR();
    }

    GLFramebuffer fbo;
    glBindFramebuffer(GL_FRAMEBUFFER, fbo);
    for (GLenum face = 0; face < 6; face++)
    {
        glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                             GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, color, 0, 4);
        ASSERT_GL_NO_ERROR();
        EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

        glClear(GL_COLOR_BUFFER_BIT);
        drawQuad(program, essl3_shaders::PositionAttrib(), 0.5f);

        // The result should be the average of the four colors written by the shader.
        EXPECT_PIXEL_COLOR_NEAR(0, 0, GLColor(121, 118, 124, 178), 1);
    }
    ASSERT_GL_NO_ERROR();
}

// Test that MSRTT rendering to multiple cubemap attachments works.
TEST_P(MSRTTES3Test, CubeMapMultipleAttachments)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture2"));

    constexpr char kFS[] = R"(#version 300 es
#extension GL_OES_sample_variables : enable
precision mediump float;
layout(location = 0) out vec4 color0;
layout(location = 1) out vec4 color1;
void main()
{
    switch (gl_SampleID % 4)
    {
    case 0:
        color0 = vec4(1.0, 0.9, 0.8, 0.7);
        color1 = vec4(0.7, 1.0, 0.9, 0.8);
        break;
    case 1:
        color0 = vec4(0.0, 0.1, 0.2, 0.3);
        color1 = vec4(0.3, 0.0, 0.1, 0.2);
        break;
    case 2:
        color0 = vec4(0.5, 0.25, 0.75, 1.0);
        color1 = vec4(1.0, 0.5, 0.25, 0.75);
        break;
    case 3:
        color0 = vec4(0.4, 0.6, 0.2, 0.8);
        color1 = vec4(0.8, 0.4, 0.6, 0.2);
        break;
    }
})";
    ANGLE_GL_PROGRAM(program, essl3_shaders::vs::Simple(), kFS);

    constexpr GLsizei kSize = 6;

    // Create multisampled framebuffer to draw into.
    GLTexture color;
    glBindTexture(GL_TEXTURE_CUBE_MAP, color);
    for (GLenum face = 0; face < 6; face++)
    {
        glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA,
                     GL_UNSIGNED_BYTE, nullptr);
        ASSERT_GL_NO_ERROR();
    }

    GLFramebuffer fbo;
    glBindFramebuffer(GL_FRAMEBUFFER, fbo);
    for (GLenum faceOffset = 0; faceOffset < 6; faceOffset += 2)
    {
        glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                             GL_TEXTURE_CUBE_MAP_POSITIVE_X + faceOffset, color, 0,
                                             4);
        glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1,
                                             GL_TEXTURE_CUBE_MAP_POSITIVE_X + 1 + faceOffset, color,
                                             0, 4);
        ASSERT_GL_NO_ERROR();
        EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

        GLenum drawBuffers[] = {GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1};
        glDrawBuffers(2, drawBuffers);

        constexpr float kClearRed[]  = {1.0f, 0.0f, 0.0f, 1.0f};
        constexpr float kClearBlue[] = {0.0f, 0.0f, 1.0f, 1.0f};
        glClearBufferfv(GL_COLOR, 0, kClearRed);
        glClearBufferfv(GL_COLOR, 1, kClearBlue);
        // Force immediate clear so that the attachments are unresolved if MSRTT is emulated.
        glReadBuffer(GL_COLOR_ATTACHMENT0);
        EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::red);
        glReadBuffer(GL_COLOR_ATTACHMENT1);
        EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::blue);

        // Draw to top left corner only
        glEnable(GL_SCISSOR_TEST);
        glScissor(0, 0, kSize / 2, kSize / 2);
        drawQuad(program, essl3_shaders::PositionAttrib(), 0.5f);
        glDisable(GL_SCISSOR_TEST);

        // The result should be the average of the four colors written by the shader.
        glReadBuffer(GL_COLOR_ATTACHMENT0);
        ASSERT_GL_NO_ERROR();
        EXPECT_PIXEL_COLOR_NEAR(0, 0, GLColor(121, 118, 124, 178), 1);
        EXPECT_PIXEL_COLOR_NEAR(kSize - 1, kSize - 1, GLColor::red, 1);

        glReadBuffer(GL_COLOR_ATTACHMENT1);
        ASSERT_GL_NO_ERROR();
        EXPECT_PIXEL_COLOR_NEAR(0, 0, GLColor(178, 121, 118, 124), 1);
        EXPECT_PIXEL_COLOR_NEAR(kSize - 1, kSize - 1, GLColor::blue, 1);
    }
    ASSERT_GL_NO_ERROR();
}

class MSRTTSRGBES3Test : public MSRTTES3Test
{};

// Test interaction between MSRTT and sRGB write control
TEST_P(MSRTTSRGBES3Test, Basic)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    ANGLE_SKIP_TEST_IF(!IsGLExtensionEnabled("GL_EXT_sRGB_write_control"));

    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_SRGB_ALPHA_EXT, 1, 1, 0, GL_SRGB_ALPHA_EXT, GL_UNSIGNED_BYTE,
                 nullptr);

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, 4);

    constexpr GLColor uniformColor(13, 54, 133, 255);
    constexpr GLColor linearColor = uniformColor;
    constexpr GLColor srgbColor(64, 127, 191, 255);

    // Setup program and uniforms
    ANGLE_GL_PROGRAM(program, essl1_shaders::vs::Simple(), essl1_shaders::fs::UniformColor());
    glUseProgram(program);
    GLint colorLocation = glGetUniformLocation(program, essl1_shaders::ColorUniform());
    ASSERT_NE(-1, colorLocation);
    glUniform4fv(colorLocation, 1, uniformColor.toNormalizedVector().data());

    // Enable sRGB encoding and render
    glEnable(GL_FRAMEBUFFER_SRGB_EXT);
    drawQuad(program, essl1_shaders::PositionAttrib(), 0.5f);
    EXPECT_GL_NO_ERROR();
    EXPECT_PIXEL_COLOR_NEAR(0, 0, srgbColor, 1.0);

    // Disable sRGB encoding and render
    glDisable(GL_FRAMEBUFFER_SRGB_EXT);
    drawQuad(program, essl1_shaders::PositionAttrib(), 0.5f);
    EXPECT_GL_NO_ERROR();
    EXPECT_PIXEL_COLOR_NEAR(0, 0, linearColor, 1.0);
}

class MultisampledRenderToTextureWithAdvancedBlendTest : public MSRTTES3Test
{
  protected:
    enum class InitMethod
    {
        Clear,
        Load,
    };

    void drawTestCommon(bool useRenderbuffer, InitMethod initMethod);
};

void MultisampledRenderToTextureWithAdvancedBlendTest::drawTestCommon(bool useRenderbuffer,
                                                                      InitMethod initMethod)
{
    constexpr char kFS[] = R"(#version 300 es
#extension GL_KHR_blend_equation_advanced : require
precision mediump float;
uniform vec4 color;
layout (blend_support_multiply) out;
layout (location = 0) out vec4 outColor;
void main() {
  outColor = color;
})";

    ANGLE_GL_PROGRAM(program, essl3_shaders::vs::Simple(), kFS);
    glUseProgram(program);

    GLint colorLoc = glGetUniformLocation(program, "color");
    ASSERT_NE(colorLoc, -1);

    GLFramebuffer FBO;
    glBindFramebuffer(GL_FRAMEBUFFER, FBO);

    // Set up color attachment and bind to FBO
    constexpr GLsizei kSize = 1;
    GLTexture texture;
    GLRenderbuffer renderbuffer;
    createAndAttachColorAttachment(useRenderbuffer, kSize, GL_COLOR_ATTACHMENT0, nullptr,
                                   mTestSampleCount, &texture, &renderbuffer);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    constexpr float kDst[4] = {1.0f, 0.25f, 0.5f, 1.0f};
    constexpr float kSrc[4] = {0.5f, 1.0f, 1.0f, 1.0f};

    glClearColor(kDst[0], kDst[1], kDst[2], kDst[3]);
    glUniform4f(colorLoc, kSrc[0], kSrc[1], kSrc[2], kSrc[3]);

    glEnable(GL_BLEND);
    glBlendEquation(GL_MULTIPLY_KHR);

    if (initMethod == InitMethod::Load)
    {
        const GLColor kInitColor(0xFF, 0x3F, 0x7F, 0xFF);
        if (useRenderbuffer)
        {
            glClear(GL_COLOR_BUFFER_BIT);
            EXPECT_PIXEL_COLOR_NEAR(0, 0, kInitColor, 1);
        }
        else
        {
            std::vector<GLColor> initData(kSize * kSize, kInitColor);
            glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, kSize, kSize, GL_RGBA, GL_UNSIGNED_BYTE,
                            initData.data());
        }
    }
    else
    {
        glClear(GL_COLOR_BUFFER_BIT);
    }
    drawQuad(program, essl3_shaders::PositionAttrib(), 0);

    EXPECT_PIXEL_COLOR_NEAR(0, 0, GLColor(0x7F, 0x3F, 0x7F, 0xFF), 1);
    ASSERT_GL_NO_ERROR();
}

// Interaction between GL_EXT_multisampled_render_to_texture and advanced blend.
TEST_P(MultisampledRenderToTextureWithAdvancedBlendTest, LoadThenDraw)
{
    ANGLE_SKIP_TEST_IF(!IsGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    ANGLE_SKIP_TEST_IF(!IsGLExtensionEnabled("GL_KHR_blend_equation_advanced"));

    drawTestCommon(false, InitMethod::Load);
}

// Same as Draw, but with renderbuffers.
TEST_P(MultisampledRenderToTextureWithAdvancedBlendTest, RenderbufferLoadThenDraw)
{
    ANGLE_SKIP_TEST_IF(!IsGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    ANGLE_SKIP_TEST_IF(!IsGLExtensionEnabled("GL_KHR_blend_equation_advanced"));

    drawTestCommon(true, InitMethod::Load);
}

// Interaction between GL_EXT_multisampled_render_to_texture and advanced blend.
TEST_P(MultisampledRenderToTextureWithAdvancedBlendTest, ClearThenDraw)
{
    ANGLE_SKIP_TEST_IF(!IsGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    ANGLE_SKIP_TEST_IF(!IsGLExtensionEnabled("GL_KHR_blend_equation_advanced"));

    drawTestCommon(false, InitMethod::Clear);
}

// Same as Draw, but with renderbuffers.
TEST_P(MultisampledRenderToTextureWithAdvancedBlendTest, RenderbufferClearThenDraw)
{
    ANGLE_SKIP_TEST_IF(!IsGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    ANGLE_SKIP_TEST_IF(!IsGLExtensionEnabled("GL_KHR_blend_equation_advanced"));

    drawTestCommon(true, InitMethod::Clear);
}

// Test that similar unresolve operations with and without stencil work.  Regression test for an
// unresolve shader cache bug where the stencil unresolve was not part of the cache key.
TEST_P(MSRTTES3Test, UnresolveWithAndWithoutStencil)
{
    ANGLE_SKIP_TEST_IF(!IsGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    ANGLE_GL_PROGRAM(program, essl1_shaders::vs::Simple(), essl1_shaders::fs::UniformColor());
    glUseProgram(program);
    GLint colorLocation = glGetUniformLocation(program, essl1_shaders::ColorUniform());
    ASSERT_NE(-1, colorLocation);

    constexpr GLint kWidth  = 13;
    constexpr GLint kHeight = 17;

    GLRenderbuffer color;
    glBindRenderbuffer(GL_RENDERBUFFER, color);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, mTestSampleCount, GL_RGBA8, kWidth,
                                        kHeight);

    GLRenderbuffer depthStencil;
    glBindRenderbuffer(GL_RENDERBUFFER, depthStencil);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, mTestSampleCount, GL_DEPTH24_STENCIL8,
                                        kWidth, kHeight);

    GLFramebuffer FBO;
    glBindFramebuffer(GL_FRAMEBUFFER, FBO);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, color);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER,
                              depthStencil);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Draw once, invalidate depth.  This makes sure that color and stencil have defined contents.
    glUniform4fv(colorLocation, 1, GLColor::red.toNormalizedVector().data());
    glEnable(GL_STENCIL_TEST);
    glStencilFunc(GL_ALWAYS, 0x55, 0xFF);
    glStencilOp(GL_REPLACE, GL_REPLACE, GL_REPLACE);
    glStencilMask(0xFF);
    drawQuad(program, essl3_shaders::PositionAttrib(), 0);

    GLenum invalidateAttachments[] = {GL_DEPTH_ATTACHMENT};
    glInvalidateFramebuffer(GL_FRAMEBUFFER, 1, invalidateAttachments);

    // Break the render pass
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::red);

    // Draw again.  Color and stencil must be unresolved.
    glEnable(GL_BLEND);
    glBlendFunc(GL_ONE, GL_ONE);
    glUniform4fv(colorLocation, 1, GLColor::green.toNormalizedVector().data());
    drawQuad(program, essl3_shaders::PositionAttrib(), 0);

    // Break the render pass again
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::yellow);

    // Remove the depth/stencil attachment.  Draw should unresolve color yet again, but this time
    // there is no stencil to unresolve.
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, 0);
    glUniform4fv(colorLocation, 1, GLColor::blue.toNormalizedVector().data());
    drawQuad(program, essl3_shaders::PositionAttrib(), 0);

    // Verify results
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::white);
}

// Test that drawing with the color attachment disabled works.
TEST_P(MSRTTES3Test, DrawDisabled)
{
    ANGLE_SKIP_TEST_IF(!IsGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    const bool hasAtomicCounters = getClientMajorVersion() == 3 && getClientMinorVersion() >= 1;
    constexpr char kFS[]         = R"(#version 310 es
precision mediump float;
uniform vec4 c;
layout(binding = 0) uniform atomic_uint ac;
out vec4 color;

void main()
{
    atomicCounterIncrement(ac);
    color = c;
})";

    ANGLE_GL_PROGRAM(program,
                     hasAtomicCounters ? essl31_shaders::vs::Simple() : essl1_shaders::vs::Simple(),
                     hasAtomicCounters ? kFS : essl1_shaders::fs::UniformColor());
    glUseProgram(program);
    GLint colorLocation =
        glGetUniformLocation(program, hasAtomicCounters ? "c" : essl1_shaders::ColorUniform());
    ASSERT_NE(-1, colorLocation);

    GLRenderbuffer color;
    glBindRenderbuffer(GL_RENDERBUFFER, color);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, mTestSampleCount, GL_RGBA8, 1, 1);

    GLFramebuffer FBO;
    glBindFramebuffer(GL_FRAMEBUFFER, FBO);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, color);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    glClearColor(0, 0, 1, 1);
    glClear(GL_COLOR_BUFFER_BIT);

    GLBuffer ac;
    constexpr GLuint kInitialData = 20;
    if (hasAtomicCounters)
    {
        glBindBuffer(GL_ATOMIC_COUNTER_BUFFER, ac);
        glBufferData(GL_ATOMIC_COUNTER_BUFFER, sizeof(kInitialData), &kInitialData, GL_STATIC_DRAW);
        glBindBufferBase(GL_ATOMIC_COUNTER_BUFFER, 0, ac);
    }

    // Draw once to create a render pass, then close it.
    constexpr GLenum kDisable = GL_NONE;
    glDrawBuffers(1, &kDisable);

    glUniform4fv(colorLocation, 1, GLColor::red.toNormalizedVector().data());
    drawQuad(program, essl1_shaders::PositionAttrib(), 0);
    // Attachment should remain blue (the clear color)
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::blue);

    if (hasAtomicCounters)
    {
        // Verify that draw actually happened by looking at the atomic counter.
        glMemoryBarrier(GL_BUFFER_UPDATE_BARRIER_BIT);
        const GLuint value = *static_cast<const GLuint *>(
            glMapBufferRange(GL_ATOMIC_COUNTER_BUFFER, 0, sizeof(GLuint), GL_MAP_READ_BIT));
        glUnmapBuffer(GL_ATOMIC_COUNTER_BUFFER);

        EXPECT_EQ(value, kInitialData + 1);
    }

    ASSERT_GL_NO_ERROR();
}

// Test that drawing with the color attachment disabled after drawing with it enabled works.
TEST_P(MSRTTES3Test, DrawThenDrawDisabled)
{
    ANGLE_SKIP_TEST_IF(!IsGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    const bool hasAtomicCounters = getClientMajorVersion() == 3 && getClientMinorVersion() >= 1;
    constexpr char kFS[]         = R"(#version 310 es
precision mediump float;
uniform vec4 c;
layout(binding = 0) uniform atomic_uint ac;
out vec4 color;

void main()
{
    atomicCounterIncrement(ac);
    color = c;
})";

    ANGLE_GL_PROGRAM(program,
                     hasAtomicCounters ? essl31_shaders::vs::Simple() : essl1_shaders::vs::Simple(),
                     hasAtomicCounters ? kFS : essl1_shaders::fs::UniformColor());
    glUseProgram(program);
    GLint colorLocation =
        glGetUniformLocation(program, hasAtomicCounters ? "c" : essl1_shaders::ColorUniform());
    ASSERT_NE(-1, colorLocation);

    GLRenderbuffer color;
    glBindRenderbuffer(GL_RENDERBUFFER, color);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, mTestSampleCount, GL_RGBA8, 1, 1);

    GLFramebuffer FBO;
    glBindFramebuffer(GL_FRAMEBUFFER, FBO);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, color);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    GLBuffer ac;
    constexpr GLuint kInitialData = 20;
    if (hasAtomicCounters)
    {
        glBindBuffer(GL_ATOMIC_COUNTER_BUFFER, ac);
        glBufferData(GL_ATOMIC_COUNTER_BUFFER, sizeof(kInitialData), &kInitialData, GL_STATIC_DRAW);
        glBindBufferBase(GL_ATOMIC_COUNTER_BUFFER, 0, ac);
    }

    // Draw once to create a render pass, then close it.
    glUniform4fv(colorLocation, 1, GLColor::red.toNormalizedVector().data());
    drawQuad(program, essl1_shaders::PositionAttrib(), 0);
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::red);

    if (hasAtomicCounters)
    {
        glMemoryBarrier(GL_ATOMIC_COUNTER_BARRIER_BIT);
    }

    // Disable the draw buffer and draw again.
    constexpr GLenum kDisable = GL_NONE;
    glDrawBuffers(1, &kDisable);

    glUniform4fv(colorLocation, 1, GLColor::green.toNormalizedVector().data());
    drawQuad(program, essl1_shaders::PositionAttrib(), 0);

    // Attachment should still be red.
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::red);

    if (hasAtomicCounters)
    {
        // Verify that both draws actually happened by looking at the atomic counter.
        glMemoryBarrier(GL_BUFFER_UPDATE_BARRIER_BIT);
        const GLuint value = *static_cast<const GLuint *>(
            glMapBufferRange(GL_ATOMIC_COUNTER_BUFFER, 0, sizeof(GLuint), GL_MAP_READ_BIT));
        glUnmapBuffer(GL_ATOMIC_COUNTER_BUFFER);

        EXPECT_EQ(value, kInitialData + 2);
    }

    ASSERT_GL_NO_ERROR();
}

// Test that drawing with the color attachment disabled then drawing with it enabled works.
TEST_P(MSRTTES3Test, DrawDisabledThenDraw)
{
    ANGLE_SKIP_TEST_IF(!IsGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    ANGLE_GL_PROGRAM(program, essl1_shaders::vs::Simple(), essl1_shaders::fs::UniformColor());
    glUseProgram(program);
    GLint colorLocation = glGetUniformLocation(program, essl1_shaders::ColorUniform());
    ASSERT_NE(-1, colorLocation);

    GLRenderbuffer color;
    glBindRenderbuffer(GL_RENDERBUFFER, color);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, mTestSampleCount, GL_RGBA8, 1, 1);

    GLFramebuffer FBO;
    glBindFramebuffer(GL_FRAMEBUFFER, FBO);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, color);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Draw once with color attachment 0 disabled.
    constexpr GLenum kDisable = GL_NONE;
    glDrawBuffers(1, &kDisable);

    glUniform4fv(colorLocation, 1, GLColor::red.toNormalizedVector().data());
    drawQuad(program, essl1_shaders::PositionAttrib(), 0);

    // Enable the draw buffer and draw again.
    constexpr GLenum kEnable = GL_COLOR_ATTACHMENT0;
    glDrawBuffers(1, &kEnable);

    glUniform4fv(colorLocation, 1, GLColor::green.toNormalizedVector().data());
    drawQuad(program, essl1_shaders::PositionAttrib(), 0);

    // Verify results
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::green);

    ASSERT_GL_NO_ERROR();
}

// Test that framebuffer fetch works with GL_EXT_multisampled_render_to_texture.
TEST_P(MSRTTES3Test, FramebufferFetchBasic)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_shader_framebuffer_fetch"));

    // Set up FBO with multisampled render to texture color attachment
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 16, 16, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

    GLFramebuffer fbo;
    glBindFramebuffer(GL_FRAMEBUFFER, fbo);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, 4);
    ASSERT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Clear color to red
    glClearColor(1.0f, 0.0f, 0.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);

    // Program with framebuffer fetch.
    // It reads the current color and adds green to it.
    // Red (1,0,0,1) + Green (0,1,0,0) = Yellow (1,1,0,1).
    const char kFS[] = R"(#version 300 es
#extension GL_EXT_shader_framebuffer_fetch : require
layout(location = 0) inout highp vec4 color;
void main()
{
    color.g += 1.0;
})";

    ANGLE_GL_PROGRAM(program, essl3_shaders::vs::Simple(), kFS);
    glUseProgram(program);

    // Draw quad to trigger framebuffer fetch
    drawQuad(program, essl3_shaders::PositionAttrib(), 0.0f);
    ASSERT_GL_NO_ERROR();

    // Verify result (should be yellow)
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::yellow);
}

// Test that framebuffer fetch works with GL_EXT_multisampled_render_to_texture.
// This variant exercises multisample data being on tile instead of memory when
// framebuffer fetch happens.
TEST_P(MSRTTES3Test, FramebufferFetchOnTile)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_shader_framebuffer_fetch"));

    // Set up FBO with multisampled render to texture color attachment
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 16, 16, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

    GLFramebuffer fbo;
    glBindFramebuffer(GL_FRAMEBUFFER, fbo);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, 4);
    ASSERT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Clear with red
    glClearColor(1.0f, 0.0f, 0.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);

    // Draw blue
    ANGLE_GL_PROGRAM(blueProgram, essl3_shaders::vs::Simple(), essl3_shaders::fs::Blue());
    drawQuad(blueProgram, essl3_shaders::PositionAttrib(), 0.0f);
    ASSERT_GL_NO_ERROR();

    // Now draw again with a fetch of the blue, add green to get cyan
    // Blue (0,0,1,1) + Green (0,1,0,0) = Cyan (0,1,1,1).
    const char kFS[] = R"(#version 300 es
#extension GL_EXT_shader_framebuffer_fetch : require
layout(location = 0) inout highp vec4 color;
void main()
{
    color.g += 1.0;
})";

    ANGLE_GL_PROGRAM(program, essl3_shaders::vs::Simple(), kFS);
    glUseProgram(program);

    drawQuad(program, essl3_shaders::PositionAttrib(), 0.0f);
    ASSERT_GL_NO_ERROR();

    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::cyan);
}

// Test that framebuffer fetch works with GL_EXT_multisampled_render_to_texture.
// This variant draws different colors based on gl_SampleID, then performs second
// draw that non-linearly transforms what it reads using square. If the driver
// breaks the render pass and resolves before the second draw call, the result will
// be different than if it truly reads the MSAA data from the previous draw.
TEST_P(MSRTTES3Test, FramebufferFetchSampleID)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_shader_framebuffer_fetch"));
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_OES_sample_variables"));

    // Set up FBO with multisampled render to texture color attachment
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 16, 16, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

    GLFramebuffer fbo;
    glBindFramebuffer(GL_FRAMEBUFFER, fbo);
    // Explicitly request 4 samples to make sample distribution predictable.
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, 4);
    ASSERT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Clear with white
    glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);

    // Draw 1: Output depends on gl_SampleID.
    // Sample 0, 2: 0.0 red
    // Sample 1, 3: 1.0 red
    // Resolved color should be 0.5 red.
    const char kFS1[] = R"(#version 300 es
#extension GL_OES_sample_variables : require
out highp vec4 color;
void main()
{
    if (gl_SampleID % 2 == 0)
        color = vec4(0.0, 0.0, 0.0, 1.0);
    else
        color = vec4(1.0, 0.0, 0.0, 1.0);
})";

    ANGLE_GL_PROGRAM(program1, essl3_shaders::vs::Simple(), kFS1);
    drawQuad(program1, essl3_shaders::PositionAttrib(), 0.0f);
    ASSERT_GL_NO_ERROR();

    // Draw 2: Reads the color and applies a non-linear transform (square).
    // If truly multisampled:
    // Sample 0: 0.0^2 = 0.0
    // Sample 1: 1.0^2 = 1.0
    // Resolved color = 0.5.
    // If resolved before Draw 2:
    // Sample 0, 1 read 0.5 -> 0.5^2 = 0.25.
    // Resolved color = 0.25.
    const char kFS2[] = R"(#version 300 es
#extension GL_EXT_shader_framebuffer_fetch : require
layout(location = 0) inout highp vec4 color;
void main()
{
    highp vec4 tempColor = vec4(0.0f, 0.0f, 0.0f, 1.0f);
    // Move the color to green channel to avoid getting stale results
    tempColor.g = color.r * color.r;
    color = tempColor;
})";

    ANGLE_GL_PROGRAM(program2, essl3_shaders::vs::Simple(), kFS2);
    drawQuad(program2, essl3_shaders::PositionAttrib(), 0.0f);
    ASSERT_GL_NO_ERROR();

    // Verify result (should be 0.5, i.e., ~127 or 128)
    // If it was resolved early, it would be 0.25 (i.e. ~64).
    // We expect it NOT to be resolved early, so value should be near 127.
    // We use a small error margin.
    // Note Draw 2 moved the color to green channel
    EXPECT_PIXEL_NEAR(0, 0, 0, 127, 0, 255, 10);
}

ANGLE_INSTANTIATE_TEST_COMBINE_1(
    MSRTTTest,
    PrintToStringParamName,
    testing::Bool(),
    ANGLE_ALL_TEST_PLATFORMS_ES2,
    ANGLE_ALL_TEST_PLATFORMS_ES3,
    ANGLE_ALL_TEST_PLATFORMS_ES31,
    ES2_METAL().enable(Feature::EnableMultisampledRenderToTextureOnNonTilers),
    ES3_METAL()
        .enable(Feature::EnableMultisampledRenderToTextureOnNonTilers)
        .enable(Feature::EmulateDontCareLoadWithRandomClear),
    ES3_VULKAN()
        .disable(Feature::SupportsExtendedDynamicState)
        .disable(Feature::SupportsExtendedDynamicState2),
    ES3_VULKAN().disable(Feature::SupportsExtendedDynamicState2),
    ES3_VULKAN().disable(Feature::SupportsSPIRV14),
    ES3_VULKAN_SWIFTSHADER().enable(Feature::EnableMultisampledRenderToTexture));

GTEST_ALLOW_UNINSTANTIATED_PARAMETERIZED_TEST(MSRTTES3Test);
ANGLE_INSTANTIATE_TEST_COMBINE_1(
    MSRTTES3Test,
    PrintToStringParamName,
    testing::Bool(),
    ANGLE_ALL_TEST_PLATFORMS_ES3,
    ANGLE_ALL_TEST_PLATFORMS_ES31,
    ES3_METAL()
        .enable(Feature::EnableMultisampledRenderToTextureOnNonTilers)
        .enable(Feature::EmulateDontCareLoadWithRandomClear),
    ES3_VULKAN()
        .disable(Feature::SupportsExtendedDynamicState)
        .disable(Feature::SupportsExtendedDynamicState2),
    ES3_VULKAN().disable(Feature::SupportsExtendedDynamicState2),
    ES3_VULKAN().disable(Feature::SupportsSPIRV14),
    ES3_VULKAN().disable(Feature::SupportsShaderStencilExport),
    ES3_VULKAN_SWIFTSHADER().enable(Feature::EnableMultisampledRenderToTexture),
    ES31_VULKAN_SWIFTSHADER().enable(Feature::EnableMultisampledRenderToTexture));

GTEST_ALLOW_UNINSTANTIATED_PARAMETERIZED_TEST(MSRTTSRGBES3Test);
ANGLE_INSTANTIATE_TEST_COMBINE_1(
    MSRTTSRGBES3Test,
    PrintToStringParamName,
    testing::Bool(),
    ANGLE_ALL_TEST_PLATFORMS_ES3,
    ES3_VULKAN().enable(Feature::AllowMultisampledRenderToTextureEmulation));

GTEST_ALLOW_UNINSTANTIATED_PARAMETERIZED_TEST(MSRTTES31Test);
ANGLE_INSTANTIATE_TEST_COMBINE_1(
    MSRTTES31Test,
    PrintToStringParamName,
    testing::Bool(),
    ANGLE_ALL_TEST_PLATFORMS_ES31,
    ES31_VULKAN()
        .disable(Feature::SupportsExtendedDynamicState)
        .disable(Feature::SupportsExtendedDynamicState2),
    ES31_VULKAN().disable(Feature::SupportsExtendedDynamicState2),
    ES31_VULKAN().disable(Feature::SupportsSPIRV14),
    ES31_VULKAN_SWIFTSHADER().enable(Feature::EnableMultisampledRenderToTexture));

GTEST_ALLOW_UNINSTANTIATED_PARAMETERIZED_TEST(MultisampledRenderToTextureWithAdvancedBlendTest);
ANGLE_INSTANTIATE_TEST_COMBINE_1(
    MultisampledRenderToTextureWithAdvancedBlendTest,
    PrintToStringParamName,
    testing::Bool(),
    ANGLE_ALL_TEST_PLATFORMS_ES3,
    ANGLE_ALL_TEST_PLATFORMS_ES31,
    ES3_VULKAN().disable(Feature::SupportsSPIRV14),
    ES3_VULKAN_SWIFTSHADER().enable(Feature::EnableMultisampledRenderToTexture));
}  // namespace