Flutter Windows Embedder
compositor_opengl.cc
Go to the documentation of this file.
1 // Copyright 2013 The Flutter Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
6 
7 #include "GLES3/gl3.h"
10 
11 namespace flutter {
12 
13 namespace {
14 
15 constexpr uint32_t kWindowFrameBufferId = 0;
16 
17 // The metadata for an OpenGL framebuffer backing store.
18 struct FramebufferBackingStore {
19  uint32_t framebuffer_id;
20  uint32_t texture_id;
21 };
22 
23 // Based off Skia's logic:
24 // https://github.com/google/skia/blob/4738ed711e03212aceec3cd502a4adb545f38e63/src/gpu/ganesh/gl/GrGLCaps.cpp#L1963-L2116
25 int GetSupportedTextureFormat(const impeller::DescriptionGLES* description) {
26  if (description->HasExtension("GL_EXT_texture_format_BGRA8888")) {
27  return GL_BGRA8_EXT;
28  } else if (description->HasExtension("GL_APPLE_texture_format_BGRA8888") &&
29  description->GetGlVersion().IsAtLeast(impeller::Version(3, 0))) {
30  return GL_BGRA8_EXT;
31  } else {
32  return GL_RGBA8;
33  }
34 }
35 
36 } // namespace
37 
39  impeller::ProcTableGLES::Resolver resolver)
40  : engine_(engine), resolver_(resolver) {}
41 
43  const FlutterBackingStoreConfig& config,
44  FlutterBackingStore* result) {
45  if (!is_initialized_ && !Initialize()) {
46  return false;
47  }
48 
49  auto store = std::make_unique<FramebufferBackingStore>();
50 
51  gl_->GenTextures(1, &store->texture_id);
52  gl_->GenFramebuffers(1, &store->framebuffer_id);
53 
54  gl_->BindFramebuffer(GL_FRAMEBUFFER, store->framebuffer_id);
55 
56  gl_->BindTexture(GL_TEXTURE_2D, store->texture_id);
57  gl_->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
58  gl_->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
59  gl_->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
60  gl_->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
61  gl_->TexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, config.size.width,
62  config.size.height, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
63  gl_->BindTexture(GL_TEXTURE_2D, 0);
64 
65  gl_->FramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0_EXT,
66  GL_TEXTURE_2D, store->texture_id, 0);
67 
68  result->type = kFlutterBackingStoreTypeOpenGL;
69  result->open_gl.type = kFlutterOpenGLTargetTypeFramebuffer;
70  result->open_gl.framebuffer.name = store->framebuffer_id;
71  result->open_gl.framebuffer.target = format_;
72  result->open_gl.framebuffer.user_data = store.release();
73  result->open_gl.framebuffer.destruction_callback = [](void* user_data) {
74  // Backing store destroyed in `CompositorOpenGL::CollectBackingStore`, set
75  // on FlutterCompositor.collect_backing_store_callback during engine start.
76  };
77  return true;
78 }
79 
80 bool CompositorOpenGL::CollectBackingStore(const FlutterBackingStore* store) {
81  FML_DCHECK(is_initialized_);
82  FML_DCHECK(store->type == kFlutterBackingStoreTypeOpenGL);
83  FML_DCHECK(store->open_gl.type == kFlutterOpenGLTargetTypeFramebuffer);
84 
85  auto user_data = static_cast<FramebufferBackingStore*>(
86  store->open_gl.framebuffer.user_data);
87 
88  gl_->DeleteFramebuffers(1, &user_data->framebuffer_id);
89  gl_->DeleteTextures(1, &user_data->texture_id);
90 
91  delete user_data;
92  return true;
93 }
94 
95 bool CompositorOpenGL::Present(const FlutterLayer** layers,
96  size_t layers_count) {
97  // TODO(loicsharma): Remove implicit view assumption.
98  // https://github.com/flutter/flutter/issues/142845
99  FlutterWindowsView* view = engine_->view(kImplicitViewId);
100  if (!view) {
101  return false;
102  }
103 
104  // Clear the view if there are no layers to present.
105  if (layers_count == 0) {
106  // Normally the compositor is initialized when the first backing store is
107  // created. However, on an empty frame no backing stores are created and
108  // the present needs to initialize the compositor.
109  if (!is_initialized_ && !Initialize()) {
110  return false;
111  }
112 
113  return Clear(view);
114  }
115 
116  // TODO: Support compositing layers and platform views.
117  // See: https://github.com/flutter/flutter/issues/31713
118  FML_DCHECK(is_initialized_);
119  FML_DCHECK(layers_count == 1);
120  FML_DCHECK(layers[0]->offset.x == 0 && layers[0]->offset.y == 0);
121  FML_DCHECK(layers[0]->type == kFlutterLayerContentTypeBackingStore);
122  FML_DCHECK(layers[0]->backing_store->type == kFlutterBackingStoreTypeOpenGL);
123  FML_DCHECK(layers[0]->backing_store->open_gl.type ==
124  kFlutterOpenGLTargetTypeFramebuffer);
125 
126  auto width = layers[0]->size.width;
127  auto height = layers[0]->size.height;
128 
129  // Check if this frame can be presented. This resizes the surface if a resize
130  // is pending and |width| and |height| match the target size.
131  if (!view->OnFrameGenerated(width, height)) {
132  return false;
133  }
134 
135  // |OnFrameGenerated| should return false if the surface isn't valid.
136  FML_DCHECK(view->surface() != nullptr);
137  FML_DCHECK(view->surface()->IsValid());
138 
139  egl::WindowSurface* surface = view->surface();
140  if (!surface->MakeCurrent()) {
141  return false;
142  }
143 
144  auto source_id = layers[0]->backing_store->open_gl.framebuffer.name;
145 
146  // Disable the scissor test as it can affect blit operations.
147  // Prevents regressions like: https://github.com/flutter/flutter/issues/140828
148  // See OpenGL specification version 4.6, section 18.3.1.
149  gl_->Disable(GL_SCISSOR_TEST);
150 
151  gl_->BindFramebuffer(GL_READ_FRAMEBUFFER, source_id);
152  gl_->BindFramebuffer(GL_DRAW_FRAMEBUFFER, kWindowFrameBufferId);
153 
154  gl_->BlitFramebuffer(0, // srcX0
155  0, // srcY0
156  width, // srcX1
157  height, // srcY1
158  0, // dstX0
159  0, // dstY0
160  width, // dstX1
161  height, // dstY1
162  GL_COLOR_BUFFER_BIT, // mask
163  GL_NEAREST // filter
164  );
165 
166  if (!surface->SwapBuffers()) {
167  return false;
168  }
169 
170  view->OnFramePresented();
171  return true;
172 }
173 
174 bool CompositorOpenGL::Initialize() {
175  FML_DCHECK(!is_initialized_);
176 
177  egl::Manager* manager = engine_->egl_manager();
178  if (!manager) {
179  return false;
180  }
181 
182  if (!manager->render_context()->MakeCurrent()) {
183  return false;
184  }
185 
186  gl_ = std::make_unique<impeller::ProcTableGLES>(resolver_);
187  if (!gl_->IsValid()) {
188  gl_.reset();
189  return false;
190  }
191 
192  format_ = GetSupportedTextureFormat(gl_->GetDescription());
193  is_initialized_ = true;
194  return true;
195 }
196 
197 bool CompositorOpenGL::Clear(FlutterWindowsView* view) {
198  FML_DCHECK(is_initialized_);
199 
200  // Check if this frame can be presented. This resizes the surface if needed.
201  if (!view->OnEmptyFrameGenerated()) {
202  return false;
203  }
204 
205  // |OnEmptyFrameGenerated| should return false if the surface isn't valid.
206  FML_DCHECK(view->surface() != nullptr);
207  FML_DCHECK(view->surface()->IsValid());
208 
209  egl::WindowSurface* surface = view->surface();
210  if (!surface->MakeCurrent()) {
211  return false;
212  }
213 
214  gl_->ClearColor(0.0f, 0.0f, 0.0f, 0.0f);
215  gl_->Clear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
216 
217  if (!surface->SwapBuffers()) {
218  return false;
219  }
220 
221  view->OnFramePresented();
222  return true;
223 }
224 
225 } // namespace flutter
flutter::kImplicitViewId
constexpr FlutterViewId kImplicitViewId
Definition: flutter_windows_engine.h:54
flutter::egl::Manager::render_context
virtual Context * render_context() const
Definition: manager.cc:318
flutter::CompositorOpenGL::Present
bool Present(const FlutterLayer **layers, size_t layers_count) override
|Compositor|
Definition: compositor_opengl.cc:95
flutter::FlutterWindowsEngine::view
FlutterWindowsView * view(FlutterViewId view_id) const
Definition: flutter_windows_engine.cc:533
flutter::FlutterWindowsView
Definition: flutter_windows_view.h:34
flutter::FlutterWindowsView::surface
egl::WindowSurface * surface() const
Definition: flutter_windows_view.cc:721
flutter::egl::WindowSurface
Definition: window_surface.h:19
user_data
void * user_data
Definition: flutter_windows_view_unittests.cc:52
flutter::CompositorOpenGL::CompositorOpenGL
CompositorOpenGL(FlutterWindowsEngine *engine, impeller::ProcTableGLES::Resolver resolver)
Definition: compositor_opengl.cc:38
flutter::FlutterWindowsEngine
Definition: flutter_windows_engine.h:89
type
enum flutter::testing::@87::KeyboardChange::Type type
flutter::egl::Context::MakeCurrent
virtual bool MakeCurrent() const
Definition: context.cc:29
flutter::CompositorOpenGL::CreateBackingStore
bool CreateBackingStore(const FlutterBackingStoreConfig &config, FlutterBackingStore *result) override
|Compositor|
Definition: compositor_opengl.cc:42
framebuffer_id
uint32_t framebuffer_id
Definition: compositor_opengl.cc:19
flutter_windows_view.h
flutter::egl::Surface::IsValid
virtual bool IsValid() const
Definition: surface.cc:19
flutter::CompositorOpenGL::CollectBackingStore
bool CollectBackingStore(const FlutterBackingStore *store) override
|Compositor|
Definition: compositor_opengl.cc:80
flutter::egl::Surface::MakeCurrent
virtual bool MakeCurrent() const
Definition: surface.cc:50
compositor_opengl.h
flutter::FlutterWindowsView::OnFrameGenerated
bool OnFrameGenerated(size_t width, size_t height)
Definition: flutter_windows_view.cc:137
flutter::egl::Surface::SwapBuffers
virtual bool SwapBuffers() const
Definition: surface.cc:59
flutter
Definition: accessibility_bridge_windows.cc:11
flutter::egl::Manager
Definition: manager.h:31
flutter_windows_engine.h
flutter::FlutterWindowsEngine::egl_manager
egl::Manager * egl_manager() const
Definition: flutter_windows_engine.h:159
texture_id
uint32_t texture_id
Definition: compositor_opengl.cc:20
flutter::FlutterWindowsView::OnFramePresented
virtual void OnFramePresented()
Definition: flutter_windows_view.cc:615