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// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <cassert>
#include <chrono>
#include <iostream>
#define GLFW_EXPOSE_NATIVE_EGL
#define GLFW_INCLUDE_GLEXT
#include <EGL/egl.h>
#include <EGL/eglext.h>
#include <array>
#include <cstring>
#include <list>
#include <unordered_map>
#include "GLFW/glfw3.h"
#include "GLFW/glfw3native.h"
#include "embedder.h"
// This value is calculated after the window is created.
static double g_pixelRatio = 1.0;
static const size_t kInitialWindowWidth = 800;
static const size_t kInitialWindowHeight = 600;
// Maximum damage history - for triple buffering we need to store damage for
// last two frames; Some Android devices (Pixel 4) use quad buffering.
static const int kMaxHistorySize = 10;
static constexpr FlutterViewId kImplicitViewId = 0;
// Keeps track of the most recent frame damages so that existing damage can
// be easily computed.
std::list<FlutterRect> damage_history_;
// Keeps track of the existing damage associated with each FBO ID
std::unordered_map<intptr_t, FlutterRect*> existing_damage_map_;
EGLDisplay display_;
EGLSurface surface_;
static_assert(FLUTTER_ENGINE_VERSION == 1,
"This Flutter Embedder was authored against the stable Flutter "
"API at version 1. There has been a serious breakage in the "
"API. Please read the ChangeLog and take appropriate action "
"before updating this assertion");
void GLFWcursorPositionCallbackAtPhase(GLFWwindow* window,
FlutterPointerPhase phase,
double x,
double y) {
FlutterPointerEvent event = {};
event.struct_size = sizeof(event);
event.phase = phase;
event.x = x * g_pixelRatio;
event.y = y * g_pixelRatio;
event.timestamp =
std::chrono::duration_cast<std::chrono::microseconds>(
std::chrono::high_resolution_clock::now().time_since_epoch())
.count();
// This example only supports a single window, therefore we assume the pointer
// event occurred in the only view, the implicit view.
event.view_id = kImplicitViewId;
FlutterEngineSendPointerEvent(
reinterpret_cast<FlutterEngine>(glfwGetWindowUserPointer(window)), &event,
1);
}
void GLFWcursorPositionCallback(GLFWwindow* window, double x, double y) {
GLFWcursorPositionCallbackAtPhase(window, FlutterPointerPhase::kMove, x, y);
}
void GLFWmouseButtonCallback(GLFWwindow* window,
int key,
int action,
int mods) {
if (key == GLFW_MOUSE_BUTTON_1 && action == GLFW_PRESS) {
double x, y;
glfwGetCursorPos(window, &x, &y);
GLFWcursorPositionCallbackAtPhase(window, FlutterPointerPhase::kDown, x, y);
glfwSetCursorPosCallback(window, GLFWcursorPositionCallback);
}
if (key == GLFW_MOUSE_BUTTON_1 && action == GLFW_RELEASE) {
double x, y;
glfwGetCursorPos(window, &x, &y);
GLFWcursorPositionCallbackAtPhase(window, FlutterPointerPhase::kUp, x, y);
glfwSetCursorPosCallback(window, nullptr);
}
}
static void GLFWKeyCallback(GLFWwindow* window,
int key,
int scancode,
int action,
int mods) {
if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS) {
glfwSetWindowShouldClose(window, GLFW_TRUE);
}
}
void GLFWwindowSizeCallback(GLFWwindow* window, int width, int height) {
FlutterWindowMetricsEvent event = {};
event.struct_size = sizeof(event);
event.width = width * g_pixelRatio;
event.height = height * g_pixelRatio;
event.pixel_ratio = g_pixelRatio;
// This example only supports a single window, therefore we assume the event
// occurred in the only view, the implicit view.
event.view_id = kImplicitViewId;
FlutterEngineSendWindowMetricsEvent(
reinterpret_cast<FlutterEngine>(glfwGetWindowUserPointer(window)),
&event);
}
// Auxiliary function used to transform a FlutterRect into the format that is
// expected by the EGL functions (i.e. array of EGLint).
static std::array<EGLint, 4> RectToInts(const FlutterRect rect) {
EGLint height;
eglQuerySurface(display_, surface_, EGL_HEIGHT, &height);
std::array<EGLint, 4> res{
static_cast<int>(rect.left), height - static_cast<int>(rect.bottom),
static_cast<int>(rect.right) - static_cast<int>(rect.left),
static_cast<int>(rect.bottom) - static_cast<int>(rect.top)};
return res;
}
// Auxiliary function to union the damage regions comprised by two FlutterRect
// element. It saves the result of this join in the rect variable.
static void JoinFlutterRect(FlutterRect* rect, FlutterRect additional_rect) {
rect->left = std::min(rect->left, additional_rect.left);
rect->top = std::min(rect->top, additional_rect.top);
rect->right = std::max(rect->right, additional_rect.right);
rect->bottom = std::max(rect->bottom, additional_rect.bottom);
}
// Auxiliary function used to check if the given list of extensions contains the
// requested extension name.
static bool HasExtension(const char* extensions, const char* name) {
const char* r = strstr(extensions, name);
auto len = strlen(name);
// check that the extension name is terminated by space or null terminator
return r != nullptr && (r[len] == ' ' || r[len] == 0);
}
bool RunFlutter(GLFWwindow* window,
const std::string& project_path,
const std::string& icudtl_path) {
FlutterRendererConfig config = {};
config.type = kOpenGL;
config.open_gl.struct_size = sizeof(config.open_gl);
config.open_gl.make_current = [](void* userdata) -> bool {
glfwMakeContextCurrent(static_cast<GLFWwindow*>(userdata));
return true;
};
config.open_gl.clear_current = [](void*) -> bool {
glfwMakeContextCurrent(nullptr); // is this even a thing?
return true;
};
config.open_gl.present_with_info =
[](void* userdata, const FlutterPresentInfo* info) -> bool {
// Free the existing damage that was allocated to this frame.
if (existing_damage_map_[info->fbo_id] != nullptr) {
free(existing_damage_map_[info->fbo_id]);
existing_damage_map_[info->fbo_id] = nullptr;
}
// Get list of extensions.
const char* extensions = eglQueryString(display_, EGL_EXTENSIONS);
// Retrieve the set damage region function.
PFNEGLSETDAMAGEREGIONKHRPROC set_damage_region_ = nullptr;
if (HasExtension(extensions, "EGL_KHR_partial_update")) {
set_damage_region_ = reinterpret_cast<PFNEGLSETDAMAGEREGIONKHRPROC>(
eglGetProcAddress("eglSetDamageRegionKHR"));
}
// Retrieve the swap buffers with damage function.
PFNEGLSWAPBUFFERSWITHDAMAGEEXTPROC swap_buffers_with_damage_ = nullptr;
if (HasExtension(extensions, "EGL_EXT_swap_buffers_with_damage")) {
swap_buffers_with_damage_ =
reinterpret_cast<PFNEGLSWAPBUFFERSWITHDAMAGEEXTPROC>(
eglGetProcAddress("eglSwapBuffersWithDamageEXT"));
} else if (HasExtension(extensions, "EGL_KHR_swap_buffers_with_damage")) {
swap_buffers_with_damage_ =
reinterpret_cast<PFNEGLSWAPBUFFERSWITHDAMAGEEXTPROC>(
eglGetProcAddress("eglSwapBuffersWithDamageKHR"));
}
if (set_damage_region_) {
// Set the buffer damage as the damage region.
auto buffer_rects = RectToInts(info->buffer_damage.damage[0]);
set_damage_region_(display_, surface_, buffer_rects.data(), 1);
}
// Add frame damage to damage history
damage_history_.push_back(info->frame_damage.damage[0]);
if (damage_history_.size() > kMaxHistorySize) {
damage_history_.pop_front();
}
if (swap_buffers_with_damage_) {
// Swap buffers with frame damage.
auto frame_rects = RectToInts(info->frame_damage.damage[0]);
return swap_buffers_with_damage_(display_, surface_, frame_rects.data(),
1);
} else {
// If the required extensions for partial repaint were not provided, do
// full repaint.
return eglSwapBuffers(display_, surface_);
}
};
config.open_gl.fbo_callback = [](void*) -> uint32_t {
return 0; // FBO0
};
config.open_gl.populate_existing_damage =
[](void* userdata, intptr_t fbo_id,
FlutterDamage* existing_damage) -> void {
// Given the FBO age, create existing damage region by joining all frame
// damages since FBO was last used
EGLint age;
if (glfwExtensionSupported("GL_EXT_buffer_age") == GLFW_TRUE) {
eglQuerySurface(display_, surface_, EGL_BUFFER_AGE_EXT, &age);
} else {
age = 4; // Virtually no driver should have a swapchain length > 4.
}
existing_damage->num_rects = 1;
// Allocate the array of rectangles for the existing damage.
existing_damage_map_[fbo_id] = static_cast<FlutterRect*>(
malloc(sizeof(FlutterRect) * existing_damage->num_rects));
existing_damage_map_[fbo_id][0] =
FlutterRect{0, 0, kInitialWindowWidth, kInitialWindowHeight};
existing_damage->damage = existing_damage_map_[fbo_id];
if (age > 1) {
--age;
// join up to (age - 1) last rects from damage history
for (auto i = damage_history_.rbegin();
i != damage_history_.rend() && age > 0; ++i, --age) {
if (i == damage_history_.rbegin()) {
if (i != damage_history_.rend()) {
existing_damage->damage[0] = {i->left, i->top, i->right, i->bottom};
}
} else {
JoinFlutterRect(&(existing_damage->damage[0]), *i);
}
}
}
};
config.open_gl.gl_proc_resolver = [](void*, const char* name) -> void* {
return reinterpret_cast<void*>(glfwGetProcAddress(name));
};
config.open_gl.fbo_reset_after_present = true;
// This directory is generated by `flutter build bundle`.
std::string assets_path = project_path + "/build/flutter_assets";
FlutterProjectArgs args = {
.struct_size = sizeof(FlutterProjectArgs),
.assets_path = assets_path.c_str(),
.icu_data_path =
icudtl_path.c_str(), // Find this in your bin/cache directory.
};
FlutterEngine engine = nullptr;
FlutterEngineResult result =
FlutterEngineRun(FLUTTER_ENGINE_VERSION, &config, // renderer
&args, window, &engine);
if (result != kSuccess || engine == nullptr) {
std::cout << "Could not run the Flutter Engine." << std::endl;
return false;
}
glfwSetWindowUserPointer(window, engine);
GLFWwindowSizeCallback(window, kInitialWindowWidth, kInitialWindowHeight);
return true;
}
void printUsage() {
std::cout
<< "usage: embedder_example_drm <path to project> <path to icudtl.dat>"
<< std::endl;
}
void GLFW_ErrorCallback(int error, const char* description) {
std::cout << "GLFW Error: (" << error << ") " << description << std::endl;
}
int main(int argc, const char* argv[]) {
if (argc != 3) {
printUsage();
return 1;
}
std::string project_path = argv[1];
std::string icudtl_path = argv[2];
glfwSetErrorCallback(GLFW_ErrorCallback);
int result = glfwInit();
if (result != GLFW_TRUE) {
std::cout << "Could not initialize GLFW." << std::endl;
return EXIT_FAILURE;
}
#if defined(__linux__)
glfwWindowHint(GLFW_CONTEXT_CREATION_API, GLFW_EGL_CONTEXT_API);
#endif
GLFWwindow* window = glfwCreateWindow(
kInitialWindowWidth, kInitialWindowHeight, "Flutter", NULL, NULL);
if (window == nullptr) {
std::cout << "Could not create GLFW window." << std::endl;
return EXIT_FAILURE;
}
int framebuffer_width, framebuffer_height;
glfwGetFramebufferSize(window, &framebuffer_width, &framebuffer_height);
g_pixelRatio = framebuffer_width / kInitialWindowWidth;
// Get the display and surface variables.
display_ = glfwGetEGLDisplay();
surface_ = glfwGetEGLSurface(window);
bool run_result = RunFlutter(window, project_path, icudtl_path);
if (!run_result) {
std::cout << "Could not run the Flutter engine." << std::endl;
return EXIT_FAILURE;
}
glfwSetKeyCallback(window, GLFWKeyCallback);
glfwSetWindowSizeCallback(window, GLFWwindowSizeCallback);
glfwSetMouseButtonCallback(window, GLFWmouseButtonCallback);
while (!glfwWindowShouldClose(window)) {
glfwWaitEvents();
}
glfwDestroyWindow(window);
glfwTerminate();
return EXIT_SUCCESS;
}