//
// Copyright 2014 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.
//

// VertexAttribImpl.h: Defines the abstract rx::VertexAttribImpl class.

#ifndef LIBANGLE_RENDERER_VERTEXARRAYIMPL_H_
#define LIBANGLE_RENDERER_VERTEXARRAYIMPL_H_

#include "common/angleutils.h"
#include "libANGLE/Buffer.h"
#include "libANGLE/VertexArray.h"
#include "libANGLE/angletypes.h"

// This is a helper X macro for iterating over all dirty attribs/bindings. Useful for dirty bits.
static_assert(gl::MAX_VERTEX_ATTRIBS == 16, "Invalid max vertex attribs");
static_assert(gl::MAX_VERTEX_ATTRIB_BINDINGS == 16, "Invalid max vertex bindings");
#define ANGLE_VERTEX_INDEX_CASES(FUNC) \
    FUNC(0)                            \
    FUNC(1)                            \
    FUNC(2)                            \
    FUNC(3)                            \
    FUNC(4)                            \
    FUNC(5) FUNC(6) FUNC(7) FUNC(8) FUNC(9) FUNC(10) FUNC(11) FUNC(12) FUNC(13) FUNC(14) FUNC(15)

namespace rx
{
class ContextImpl;

class VertexArrayImpl : angle::NonCopyable
{
  public:
    VertexArrayImpl(const gl::VertexArrayState &state,
                    const gl::VertexArrayBuffers &vertexArrayBuffers)
        : mState(state), mVertexArrayBuffers(vertexArrayBuffers)
    {
        // ElementBuffer always observe the buffer content change.
        mContentsObserverBindingsMask.set(gl::kElementArrayBufferIndex);
    }

    // This gives backend an opportunity to check buffers to see if buffer has been modified that
    // requires VertexArray sync.
    virtual gl::VertexArray::DirtyBits checkBufferForDirtyBits(
        const gl::Context *context,
        const gl::VertexArrayBufferBindingMask bufferBindingMask);

    // It's up to the implementation to reset the attrib and binding dirty bits.
    // This is faster than the front-end having to clear all the bits after they have been scanned.
    virtual angle::Result syncState(const gl::Context *context,
                                    const gl::VertexArray::DirtyBits &dirtyBits,
                                    gl::VertexArray::DirtyAttribBitsArray *attribBits,
                                    gl::VertexArray::DirtyBindingBitsArray *bindingBits);

    virtual void destroy(const gl::Context *context) {}
    virtual ~VertexArrayImpl() {}

    const gl::VertexArrayState &getState() const { return mState; }

    gl::VertexArrayBufferBindingMask getContentObserversBindingMask() const
    {
        return mContentsObserverBindingsMask;
    }

    virtual angle::Result onLabelUpdate(const gl::Context *context);

    gl::Buffer *getElementArrayBuffer() const
    {
        return mVertexArrayBuffers[gl::kElementArrayBufferIndex].get();
    }
    gl::Buffer *getVertexArrayBuffer(size_t bindingIndex) const
    {
        ASSERT(bindingIndex != gl::kElementArrayBufferIndex);
        return mVertexArrayBuffers[bindingIndex].get();
    }

    const gl::BindingPointer<gl::Buffer> &getBufferBindingPointer(size_t bindingIndex) const
    {
        return mVertexArrayBuffers[bindingIndex];
    }

  protected:
    const gl::VertexArrayState &mState;
    const gl::VertexArrayBuffers &mVertexArrayBuffers;
    // Tracks back end's needs for buffer content change at each binding index. If the bit is set,
    // current context's VertexArray will be notified when a related buffer data has changed along
    // with this bit mask.
    gl::VertexArrayBufferBindingMask mContentsObserverBindingsMask;
};

inline gl::VertexArray::DirtyBits VertexArrayImpl::checkBufferForDirtyBits(
    const gl::Context *context,
    const gl::VertexArrayBufferBindingMask bufferBindingMask)
{
    // For now we just simply assume buffer storage has changed and always dirty all
    // binding points.
    uint64_t bits = bufferBindingMask.bits();
    bits <<= gl::VertexArray::DIRTY_BIT_BINDING_0;
    return gl::VertexArray::DirtyBits(bits);
}

inline angle::Result VertexArrayImpl::syncState(const gl::Context *context,
                                                const gl::VertexArray::DirtyBits &dirtyBits,
                                                gl::VertexArray::DirtyAttribBitsArray *attribBits,
                                                gl::VertexArray::DirtyBindingBitsArray *bindingBits)
{
    return angle::Result::Continue;
}

}  // namespace rx

#endif  // LIBANGLE_RENDERER_VERTEXARRAYIMPL_H_