Match Windows logic for picking RGB/BGR textures.

shell/platform/linux/fl_framebuffer.cc

@@ -39,7 +39,7 @@ static void fl_framebuffer_class_init(FlFramebufferClass* klass) {
 
 static void fl_framebuffer_init(FlFramebuffer* self) {}
 
-FlFramebuffer* fl_framebuffer_new(size_t width, size_t height) {
+FlFramebuffer* fl_framebuffer_new(GLint format, size_t width, size_t height) {
   FlFramebuffer* provider =
       FL_FRAMEBUFFER(g_object_new(fl_framebuffer_get_type(), nullptr));
 
@@ -56,12 +56,12 @@ FlFramebuffer* fl_framebuffer_new(size_t width, size_t height) {
   glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
-  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, width, height, 0, GL_RGBA,
+  glTexImage2D(GL_TEXTURE_2D, 0, format, width, height, 0, format,
                GL_UNSIGNED_BYTE, NULL);
   glBindTexture(GL_TEXTURE_2D, 0);
 
-  glFramebufferTexture2D(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT,
-                         GL_TEXTURE_2D, provider->texture_id, 0);
+  glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
+                         provider->texture_id, 0);
 
   return provider;
 }
@@ -78,31 +78,6 @@ GLenum fl_framebuffer_get_target(FlFramebuffer* self) {
   return GL_TEXTURE_2D;
 }
 
-GLenum fl_framebuffer_get_format(FlFramebuffer* self) {
-  // Flutter defines SK_R32_SHIFT=16, so SK_PMCOLOR_BYTE_ORDER should be BGRA.
-  // In Linux kN32_SkColorType is assumed to be kBGRA_8888_SkColorType.
-  // So we must choose a valid gl format to be compatible with surface format
-  // BGRA8.
-  // Following logic is copied from Skia GrGLCaps.cpp:
-  // https://github.com/google/skia/blob/4738ed711e03212aceec3cd502a4adb545f38e63/src/gpu/ganesh/gl/GrGLCaps.cpp#L1963-L2116
-
-  if (epoxy_is_desktop_gl()) {
-    // For OpenGL.
-    if (epoxy_gl_version() >= 12 || epoxy_has_gl_extension("GL_EXT_bgra")) {
-      return GL_RGBA8;
-    }
-  } else {
-    // For OpenGL ES.
-    if (epoxy_has_gl_extension("GL_EXT_texture_format_BGRA8888") ||
-        (epoxy_has_gl_extension("GL_APPLE_texture_format_BGRA8888") &&
-         epoxy_gl_version() >= 30)) {
-      return GL_BGRA8_EXT;
-    }
-  }
-  g_critical("Failed to determine valid GL format for Flutter rendering");
-  return GL_RGBA8;
-}
-
 size_t fl_framebuffer_get_width(FlFramebuffer* self) {
   return self->width;
 }

shell/platform/linux/fl_framebuffer.h

@@ -21,14 +21,15 @@ G_DECLARE_FINAL_TYPE(FlFramebuffer, fl_framebuffer, FL, FRAMEBUFFER, GObject)
 
 /**
  * fl_framebuffer_new:
+ * @format: format, e.g. GL_RGB, GL_BGR
  * @width: width of texture.
  * @height: height of texture.
  *
  * Creates a new frame buffer. Requires a valid OpenGL context to create.
  *
  * Returns: a new #FlFramebuffer.
  */
-FlFramebuffer* fl_framebuffer_new(size_t width, size_t height);
+FlFramebuffer* fl_framebuffer_new(GLint format, size_t width, size_t height);
 
 /**
  * fl_framebuffer_get_id:
@@ -60,16 +61,6 @@ GLuint fl_framebuffer_get_texture_id(FlFramebuffer* framebuffer);
  */
 GLenum fl_framebuffer_get_target(FlFramebuffer* framebuffer);
 
-/**
- * fl_framebuffer_get_format:
- * @framebuffer: an #FlFramebuffer.
- *
- * Gets format of texture backing the framebuffer (example GL_RGBA8).
- *
- * Returns: texture format.
- */
-GLenum fl_framebuffer_get_format(FlFramebuffer* framebuffer);
-
 /**
  * fl_framebuffer_get_width:
  * @framebuffer: an #FlFramebuffer.

shell/platform/linux/fl_renderer.cc

@@ -42,6 +42,15 @@ typedef struct {
   // Engine we are rendering.
   GWeakRef engine;
 
+  // Flag to track lazy initialization.
+  gboolean initialized;
+
+  // The pixel format passed to the engine.
+  GLint sized_format;
+
+  // The format used to create textures.
+  GLint general_format;
+
   // Views being rendered.
   GHashTable* views;
 
@@ -105,6 +114,25 @@ static GLfloat pixels_to_gl_coords(GLfloat position, GLfloat pixels) {
   return (2.0 * position / pixels) - 1.0;
 }
 
+// Perform single run OpenGL initialization.
+static void initialize(FlRenderer* self) {
+  FlRendererPrivate* priv = reinterpret_cast<FlRendererPrivate*>(
+      fl_renderer_get_instance_private(self));
+
+  if (priv->initialized) {
+    return;
+  }
+  priv->initialized = TRUE;
+
+  if (epoxy_has_gl_extension("GL_EXT_texture_format_BGRA8888")) {
+    priv->sized_format = GL_BGRA8_EXT;
+    priv->general_format = GL_BGRA_EXT;
+  } else {
+    priv->sized_format = GL_RGBA8;
+    priv->general_format = GL_RGBA;
+  }
+}
+
 static void fl_renderer_unblock_main_thread(FlRenderer* self) {
   FlRendererPrivate* priv = reinterpret_cast<FlRendererPrivate*>(
       fl_renderer_get_instance_private(self));
@@ -328,13 +356,18 @@ guint32 fl_renderer_get_fbo(FlRenderer* self) {
 }
 
 gboolean fl_renderer_create_backing_store(
-    FlRenderer* renderer,
+    FlRenderer* self,
     const FlutterBackingStoreConfig* config,
     FlutterBackingStore* backing_store_out) {
-  fl_renderer_make_current(renderer);
+  FlRendererPrivate* priv = reinterpret_cast<FlRendererPrivate*>(
+      fl_renderer_get_instance_private(self));
+
+  fl_renderer_make_current(self);
+
+  initialize(self);
 
-  FlFramebuffer* framebuffer =
-      fl_framebuffer_new(config->size.width, config->size.height);
+  FlFramebuffer* framebuffer = fl_framebuffer_new(
+      priv->general_format, config->size.width, config->size.height);
   if (!framebuffer) {
     g_warning("Failed to create backing store");
     return FALSE;
@@ -345,8 +378,7 @@ gboolean fl_renderer_create_backing_store(
   backing_store_out->open_gl.framebuffer.user_data = framebuffer;
   backing_store_out->open_gl.framebuffer.name =
       fl_framebuffer_get_id(framebuffer);
-  backing_store_out->open_gl.framebuffer.target =
-      fl_framebuffer_get_format(framebuffer);
+  backing_store_out->open_gl.framebuffer.target = priv->sized_format;
   backing_store_out->open_gl.framebuffer.destruction_callback = [](void* p) {
     // Backing store destroyed in fl_renderer_collect_backing_store(), set
     // on FlutterCompositor.collect_backing_store_callback during engine start.

shell/platform/linux/fl_renderer_test.cc

@@ -52,7 +52,8 @@ TEST(FlRendererTest, RestoresGLState) {
   g_autoptr(FlDartProject) project = fl_dart_project_new();
   g_autoptr(FlView) view = fl_view_new(project);
   g_autoptr(FlMockRenderer) renderer = fl_mock_renderer_new();
-  g_autoptr(FlFramebuffer) framebuffer = fl_framebuffer_new(kWidth, kHeight);
+  g_autoptr(FlFramebuffer) framebuffer =
+      fl_framebuffer_new(GL_RGB, kWidth, kHeight);
 
   fl_renderer_add_view(FL_RENDERER(renderer), 0, view);
   fl_renderer_wait_for_frame(FL_RENDERER(renderer), kWidth, kHeight);
@@ -144,6 +145,8 @@ TEST(FlRendererTest, BlitFramebufferExtension) {
           ::testing::Return(reinterpret_cast<const GLubyte*>("Intel")));
   ON_CALL(epoxy, epoxy_is_desktop_gl).WillByDefault(::testing::Return(true));
   EXPECT_CALL(epoxy, epoxy_gl_version).WillRepeatedly(::testing::Return(20));
+  EXPECT_CALL(epoxy, epoxy_has_gl_extension(::testing::_))
+      .WillRepeatedly(::testing::Return(false));
   EXPECT_CALL(epoxy, epoxy_has_gl_extension(
                          ::testing::StrEq("GL_EXT_framebuffer_blit")))
       .WillRepeatedly(::testing::Return(true));