#include "fl_compositor_opengl.h"
#include <epoxy/egl.h>
#include <epoxy/gl.h>
#include "flutter/common/constants.h"
#include "flutter/shell/platform/embedder/embedder.h"
#include "flutter/shell/platform/linux/fl_compositor_opengl_shader.h"
#include "flutter/shell/platform/linux/fl_engine_private.h"
#include "flutter/shell/platform/linux/fl_framebuffer.h"

Classes
struct	_FlCompositorOpenGL

Functions
	G_DEFINE_TYPE (FlCompositorOpenGL, fl_compositor_opengl, fl_compositor_get_type()) static void composite_layer(FlCompositorOpenGL *self

	fl_compositor_opengl_shader_set_offset (self->shader,(2 x/width) - 1.0,(2 y/height) - 1.0)

	fl_compositor_opengl_shader_set_scale (self->shader, texture_width/width, texture_height/height)

	glBindTexture (GL_TEXTURE_2D, texture_id)

	glDrawArrays (GL_TRIANGLES, 0, 6)

static gboolean	fl_compositor_opengl_present_layers (FlCompositor compositor, const FlutterLayer *layers, size_t layers_count)

static void	fl_compositor_opengl_get_frame_size (FlCompositor compositor, size_t width, size_t *height)

static gboolean	fl_compositor_opengl_render (FlCompositor compositor, cairo_t cr, GdkWindow *window, gboolean wait_for_frame)

static void	fl_compositor_opengl_dispose (GObject *object)

static void	fl_compositor_opengl_class_init (FlCompositorOpenGLClass *klass)

static void	fl_compositor_opengl_init (FlCompositorOpenGL *self)

FlCompositorOpenGL *	fl_compositor_opengl_new (FlTaskRunner task_runner, FlOpenGLManager opengl_manager, gboolean shareable)

Variables
FlFramebuffer *	framebuffer

FlFramebuffer double	x

FlFramebuffer double double	y

FlFramebuffer double double int	width

FlFramebuffer double double int int	height

size_t	texture_height = fl_framebuffer_get_height(framebuffer)

GLuint	texture_id = fl_framebuffer_get_texture_id(framebuffer)

Function Documentation

◆ fl_compositor_opengl_class_init()

static void fl_compositor_opengl_class_init ( FlCompositorOpenGLClass * klass )

static

Definition at line 324 of file fl_compositor_opengl.cc.

                                                                            {
  FL_COMPOSITOR_CLASS(klass)->present_layers =
      fl_compositor_opengl_present_layers;
  FL_COMPOSITOR_CLASS(klass)->get_frame_size =
      fl_compositor_opengl_get_frame_size;
  FL_COMPOSITOR_CLASS(klass)->render = fl_compositor_opengl_render;
 
  G_OBJECT_CLASS(klass)->dispose = fl_compositor_opengl_dispose;
}

References fl_compositor_opengl_dispose(), fl_compositor_opengl_get_frame_size(), fl_compositor_opengl_present_layers(), and fl_compositor_opengl_render().

◆ fl_compositor_opengl_dispose()

static void fl_compositor_opengl_dispose ( GObject * object )

static

Definition at line 310 of file fl_compositor_opengl.cc.

                                                          {
  FlCompositorOpenGL* self = FL_COMPOSITOR_OPENGL(object);
 
  g_clear_object(&self->shader);
 
  g_clear_object(&self->task_runner);
  g_clear_object(&self->opengl_manager);
  g_clear_object(&self->framebuffer);
  g_clear_pointer(&self->pixels, g_free);
  g_mutex_clear(&self->frame_mutex);
 
  G_OBJECT_CLASS(fl_compositor_opengl_parent_class)->dispose(object);
}

References self.

Referenced by fl_compositor_opengl_class_init().

◆ fl_compositor_opengl_get_frame_size()

static void fl_compositor_opengl_get_frame_size	(	FlCompositor *	compositor,
		size_t *	width,
		size_t *	height
	)

static

Definition at line 211 of file fl_compositor_opengl.cc.

                                                                {
  FlCompositorOpenGL* self = FL_COMPOSITOR_OPENGL(compositor);
 
  g_autoptr(GMutexLocker) locker = g_mutex_locker_new(&self->frame_mutex);
 
  if (width != nullptr) {
    *width = self->framebuffer != nullptr
                 ? fl_framebuffer_get_width(self->framebuffer)
                 : 0;
  }
  if (height != nullptr) {
    *height = self->framebuffer != nullptr
                  ? fl_framebuffer_get_height(self->framebuffer)
                  : 0;
  }
}

References fl_framebuffer_get_height(), fl_framebuffer_get_width(), g_autoptr(), height, self, and width.

Referenced by fl_compositor_opengl_class_init().

◆ fl_compositor_opengl_init()

static void fl_compositor_opengl_init ( FlCompositorOpenGL * self )

static

Definition at line 334 of file fl_compositor_opengl.cc.

                                                                {
  g_mutex_init(&self->frame_mutex);
}

References self.

◆ fl_compositor_opengl_new()

FlCompositorOpenGL * fl_compositor_opengl_new	(	FlTaskRunner *	task_runner,
		FlOpenGLManager *	opengl_manager,
		gboolean	shareable
	)

Definition at line 338 of file fl_compositor_opengl.cc.

                                                                 {
  FlCompositorOpenGL* self = FL_COMPOSITOR_OPENGL(
      g_object_new(fl_compositor_opengl_get_type(), nullptr));
 
  self->task_runner = FL_TASK_RUNNER(g_object_ref(task_runner));
  self->shareable = shareable;
  self->opengl_manager = FL_OPENGL_MANAGER(g_object_ref(opengl_manager));
  self->shader = fl_compositor_opengl_shader_new(opengl_manager);
 
  return self;
}

References fl_compositor_opengl_shader_new(), opengl_manager, self, and shareable.

Referenced by FlCompositorOpenGLTest::SetUp(), and setup_opengl().

◆ fl_compositor_opengl_present_layers()

static gboolean fl_compositor_opengl_present_layers	(	FlCompositor *	compositor,
		const FlutterLayer **	layers,
		size_t	layers_count
	)

static

Definition at line 64 of file fl_compositor_opengl.cc.

                                                                         {
  FlCompositorOpenGL* self = FL_COMPOSITOR_OPENGL(compositor);
 
  g_mutex_lock(&self->frame_mutex);
  if (layers_count == 0) {
    g_mutex_unlock(&self->frame_mutex);
    return TRUE;
  }
 
  GLint general_format = GL_RGBA;
  if (epoxy_has_gl_extension("GL_EXT_texture_format_BGRA8888")) {
    general_format = GL_BGRA_EXT;
  }
 
  // Save bindings that are set by this function.  All bindings must be restored
  // to their original values because Skia expects that its bindings have not
  // been altered.
  GLint saved_texture_binding;
  glGetIntegerv(GL_TEXTURE_BINDING_2D, &saved_texture_binding);
  GLint saved_vao_binding;
  glGetIntegerv(GL_VERTEX_ARRAY_BINDING, &saved_vao_binding);
  GLint saved_array_buffer_binding;
  glGetIntegerv(GL_ARRAY_BUFFER_BINDING, &saved_array_buffer_binding);
  GLint saved_draw_framebuffer_binding;
  glGetIntegerv(GL_DRAW_FRAMEBUFFER_BINDING, &saved_draw_framebuffer_binding);
  GLint saved_read_framebuffer_binding;
  glGetIntegerv(GL_READ_FRAMEBUFFER_BINDING, &saved_read_framebuffer_binding);
  GLint saved_current_program;
  glGetIntegerv(GL_CURRENT_PROGRAM, &saved_current_program);
  GLboolean saved_scissor_test = glIsEnabled(GL_SCISSOR_TEST);
  GLboolean saved_blend = glIsEnabled(GL_BLEND);
  GLint saved_src_rgb;
  glGetIntegerv(GL_BLEND_SRC_RGB, &saved_src_rgb);
  GLint saved_src_alpha;
  glGetIntegerv(GL_BLEND_SRC_ALPHA, &saved_src_alpha);
  GLint saved_dst_rgb;
  glGetIntegerv(GL_BLEND_DST_RGB, &saved_dst_rgb);
  GLint saved_dst_alpha;
  glGetIntegerv(GL_BLEND_DST_ALPHA, &saved_dst_alpha);
 
  // Update framebuffer to write into.
  size_t width = layers[0]->size.width;
  size_t height = layers[0]->size.height;
  if (self->framebuffer == nullptr ||
      fl_framebuffer_get_width(self->framebuffer) != width ||
      fl_framebuffer_get_height(self->framebuffer) != height) {
    g_clear_object(&self->framebuffer);
    self->framebuffer =
        fl_framebuffer_new(general_format, width, height, self->shareable);
 
    // If not shareable make buffer to copy frame pixels into.
    if (!self->shareable) {
      size_t data_length = width * height * 4;
      self->pixels =
          static_cast<uint8_t*>(g_realloc(self->pixels, data_length));
    }
  }
 
  // FIXME(robert-ancell): The vertex array is the same for all views, but
  // cannot be shared in OpenGL. Find a way to not generate this every time.
  GLuint vao;
  glGenVertexArrays(1, &vao);
  glBindVertexArray(vao);
 
  glEnable(GL_BLEND);
  glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 
  fl_compositor_opengl_shader_use(self->shader);
 
  // Disable the scissor test as it can affect blit operations.
  // Prevents regressions like: https://github.com/flutter/flutter/issues/140828
  // See OpenGL specification version 4.6, section 18.3.1.
  glDisable(GL_SCISSOR_TEST);
 
  glBindFramebuffer(GL_DRAW_FRAMEBUFFER,
                    fl_framebuffer_get_id(self->framebuffer));
  gboolean first_layer = TRUE;
  for (size_t i = 0; i < layers_count; ++i) {
    const FlutterLayer* layer = layers[i];
    switch (layer->type) {
      case kFlutterLayerContentTypeBackingStore: {
        const FlutterBackingStore* backing_store = layer->backing_store;
        FlFramebuffer* framebuffer =
            FL_FRAMEBUFFER(backing_store->open_gl.framebuffer.user_data);
        glBindFramebuffer(GL_READ_FRAMEBUFFER,
                          fl_framebuffer_get_id(framebuffer));
        // The first layer can be blitted, and following layers composited with
        // this.
        if (first_layer) {
          glBlitFramebuffer(layer->offset.x, layer->offset.y, layer->size.width,
                            layer->size.height, layer->offset.x,
                            layer->offset.y, layer->size.width,
                            layer->size.height, GL_COLOR_BUFFER_BIT,
                            GL_NEAREST);
          first_layer = FALSE;
        } else {
          composite_layer(self, framebuffer, layer->offset.x, layer->offset.y,
                          width, height);
        }
      } break;
      case kFlutterLayerContentTypePlatformView: {
        // TODO(robert-ancell) Not implemented -
        // https://github.com/flutter/flutter/issues/41724
      } break;
    }
  }
  glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
  glFlush();
 
  glDeleteVertexArrays(1, &vao);
 
  if (saved_blend) {
    glEnable(GL_BLEND);
  } else {
    glDisable(GL_BLEND);
  }
  if (saved_scissor_test) {
    glEnable(GL_SCISSOR_TEST);
  } else {
    glDisable(GL_SCISSOR_TEST);
  }
 
  glBindTexture(GL_TEXTURE_2D, saved_texture_binding);
  glBindVertexArray(saved_vao_binding);
  glBindBuffer(GL_ARRAY_BUFFER, saved_array_buffer_binding);
  glBindFramebuffer(GL_DRAW_FRAMEBUFFER, saved_draw_framebuffer_binding);
  glUseProgram(saved_current_program);
  glBlendFuncSeparate(saved_src_rgb, saved_dst_rgb, saved_src_alpha,
                      saved_dst_alpha);
 
  if (!self->shareable) {
    glBindFramebuffer(GL_READ_FRAMEBUFFER,
                      fl_framebuffer_get_id(self->framebuffer));
    glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, self->pixels);
    glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
  }
  glBindFramebuffer(GL_READ_FRAMEBUFFER, saved_read_framebuffer_binding);
 
  g_mutex_unlock(&self->frame_mutex);
 
  fl_task_runner_stop_wait(self->task_runner);
 
  return TRUE;
}

References FlutterLayer::backing_store, epoxy_has_gl_extension(), fl_compositor_opengl_shader_use(), fl_framebuffer_get_height(), fl_framebuffer_get_id(), fl_framebuffer_get_width(), fl_framebuffer_new(), fl_task_runner_stop_wait(), FlutterOpenGLBackingStore::framebuffer, framebuffer, glBindTexture(), FlutterSize::height, height, i, kFlutterLayerContentTypeBackingStore, kFlutterLayerContentTypePlatformView, layers, layers_count, FlutterLayer::offset, FlutterBackingStore::open_gl, self, FlutterLayer::size, TRUE, FlutterLayer::type, FlutterOpenGLFramebuffer::user_data, FlutterSize::width, width, FlutterPoint::x, and FlutterPoint::y.

Referenced by fl_compositor_opengl_class_init().

◆ fl_compositor_opengl_render()

static gboolean fl_compositor_opengl_render	(	FlCompositor *	compositor,
		cairo_t *	cr,
		GdkWindow *	window,
		gboolean	wait_for_frame
	)

static

Definition at line 230 of file fl_compositor_opengl.cc.

                                                                     {
  FlCompositorOpenGL* self = FL_COMPOSITOR_OPENGL(compositor);
 
  g_mutex_lock(&self->frame_mutex);
  if (self->framebuffer == nullptr) {
    g_mutex_unlock(&self->frame_mutex);
    return FALSE;
  }
 
  // If frame not ready, then wait for it.
  gint scale_factor = gdk_window_get_scale_factor(window);
  size_t width, height;
  gint64 expiry_time =
      g_get_monotonic_time() + kCompositorRenderTimeoutMicroseconds;
  while (true) {
    width = gdk_window_get_width(window) * scale_factor;
    height = gdk_window_get_height(window) * scale_factor;
    if (!wait_for_frame) {
      break;
    }
 
    size_t framebuffer_width = fl_framebuffer_get_width(self->framebuffer);
    size_t framebuffer_height = fl_framebuffer_get_height(self->framebuffer);
    if (framebuffer_width == width && framebuffer_height == height) {
      break;
    }
 
    if (g_get_monotonic_time() > expiry_time) {
      g_warning(
          "Timed out waiting for OpenGL frame of size %zdx%zd (have %zdx%zd)",
          width, height, framebuffer_width, framebuffer_height);
      break;
    }
 
    g_mutex_unlock(&self->frame_mutex);
    fl_task_runner_wait(self->task_runner, expiry_time);
    g_mutex_lock(&self->frame_mutex);
  }
 
  if (fl_framebuffer_get_shareable(self->framebuffer)) {
    g_autoptr(FlFramebuffer) sibling =
        fl_framebuffer_create_sibling(self->framebuffer);
    gdk_cairo_draw_from_gl(cr, window, fl_framebuffer_get_texture_id(sibling),
                           GL_TEXTURE, scale_factor, 0, 0, width, height);
  } else {
    GLint saved_texture_binding;
    glGetIntegerv(GL_TEXTURE_BINDING_2D, &saved_texture_binding);
 
    GLuint texture_id;
    glGenTextures(1, &texture_id);
    glBindTexture(GL_TEXTURE_2D, texture_id);
    GLsizei fb_width = 0;
    GLsizei fb_height = 0;
    if (self->framebuffer != nullptr) {
      fb_width =
          static_cast<GLsizei>(fl_framebuffer_get_width(self->framebuffer));
      fb_height =
          static_cast<GLsizei>(fl_framebuffer_get_height(self->framebuffer));
    }
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, fb_width, fb_height, 0, GL_RGBA,
                 GL_UNSIGNED_BYTE, self->pixels);
 
    gdk_cairo_draw_from_gl(cr, window, texture_id, GL_TEXTURE, scale_factor, 0,
                           0, width, height);
 
    glDeleteTextures(1, &texture_id);
 
    glBindTexture(GL_TEXTURE_2D, saved_texture_binding);
  }
 
  glFlush();
 
  g_mutex_unlock(&self->frame_mutex);
 
  return TRUE;
}