Fix Linux Impeller support broken by incorrect deletion of stencil buffer. (#168668)

The buffer was leaking and deleted in
9d8e5e0b2f. This fixes the location where
the buffer is deleted.

engine/src/flutter/shell/platform/linux/fl_framebuffer.cc

@@ -20,6 +20,9 @@ struct _FlFramebuffer {
 
   // Texture backing framebuffer.
   GLuint texture_id;
+
+  // Stencil buffer associated with this framebuffer.
+  GLuint depth_stencil;
 };
 
 G_DEFINE_TYPE(FlFramebuffer, fl_framebuffer, G_TYPE_OBJECT)
@@ -29,6 +32,7 @@ static void fl_framebuffer_dispose(GObject* object) {
 
   glDeleteFramebuffers(1, &self->framebuffer_id);
   glDeleteTextures(1, &self->texture_id);
+  glDeleteRenderbuffers(1, &self->depth_stencil);
 
   G_OBJECT_CLASS(fl_framebuffer_parent_class)->dispose(object);
 }
@@ -63,19 +67,17 @@ FlFramebuffer* fl_framebuffer_new(GLint format, size_t width, size_t height) {
   glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                          provider->texture_id, 0);
 
-  GLuint depth_stencil;
+  glGenRenderbuffers(1, &provider->depth_stencil);
-  glGenRenderbuffers(1, &depth_stencil);
+  glBindRenderbuffer(GL_RENDERBUFFER, provider->depth_stencil);
-  glBindRenderbuffer(GL_RENDERBUFFER, depth_stencil);
   glRenderbufferStorage(GL_RENDERBUFFER,      // target
                         GL_DEPTH24_STENCIL8,  // internal format
                         width,                // width
                         height                // height
   );
   glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
-                            GL_RENDERBUFFER, depth_stencil);
+                            GL_RENDERBUFFER, provider->depth_stencil);
   glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT,
-                            GL_RENDERBUFFER, depth_stencil);
+                            GL_RENDERBUFFER, provider->depth_stencil);
-  glDeleteRenderbuffers(1, &depth_stencil);
 
   return provider;
 }

engine/src/flutter/shell/platform/linux/fl_framebuffer_test.cc

@@ -24,3 +24,17 @@ TEST(FlFramebufferTest, HasDepthStencil) {
                                         &stencil_type);
   EXPECT_NE(stencil_type, GL_NONE);
 }
+
+TEST(FlFramebufferTest, ResourcesRemoved) {
+  ::testing::NiceMock<flutter::testing::MockEpoxy> epoxy;
+
+  EXPECT_CALL(epoxy, glGenFramebuffers);
+  EXPECT_CALL(epoxy, glGenTextures);
+  EXPECT_CALL(epoxy, glGenRenderbuffers);
+  FlFramebuffer* framebuffer = fl_framebuffer_new(GL_RGB, 100, 100);
+
+  EXPECT_CALL(epoxy, glDeleteFramebuffers);
+  EXPECT_CALL(epoxy, glDeleteTextures);
+  EXPECT_CALL(epoxy, glDeleteRenderbuffers);
+  g_object_unref(framebuffer);
+}

engine/src/flutter/shell/platform/linux/testing/mock_epoxy.cc

@@ -401,11 +401,25 @@ GLuint _glCreateShader(GLenum shaderType) {
   return 0;
 }
 
-void _glDeleteFramebuffers(GLsizei n, const GLuint* framebuffers) {}
+void _glDeleteFramebuffers(GLsizei n, const GLuint* framebuffers) {
+  if (mock) {
+    mock->glDeleteFramebuffers(n, framebuffers);
+  }
+}
+
+void _glDeleteRenderbuffers(GLsizei n, const GLuint* renderbuffers) {
+  if (mock) {
+    mock->glDeleteRenderbuffers(n, renderbuffers);
+  }
+}
 
 void _glDeleteShader(GLuint shader) {}
 
-void _glDeleteTextures(GLsizei n, const GLuint* textures) {}
+void _glDeleteTextures(GLsizei n, const GLuint* textures) {
+  if (mock) {
+    mock->glDeleteTextures(n, textures);
+  }
+}
 
 static void _glFramebufferRenderbuffer(GLenum target,
                                        GLenum attachment,
@@ -424,18 +438,27 @@ static void _glGenTextures(GLsizei n, GLuint* textures) {
   for (GLsizei i = 0; i < n; i++) {
     textures[i] = 0;
   }
+  if (mock) {
+    mock->glGenTextures(n, textures);
+  }
 }
 
 static void _glGenFramebuffers(GLsizei n, GLuint* framebuffers) {
   for (GLsizei i = 0; i < n; i++) {
     framebuffers[i] = 0;
   }
+  if (mock) {
+    mock->glGenFramebuffers(n, framebuffers);
+  }
 }
 
 static void _glGenRenderbuffers(GLsizei n, GLuint* renderbuffers) {
   for (GLsizei i = 0; i < n; i++) {
     renderbuffers[i] = 0;
   }
+  if (mock) {
+    mock->glGenRenderbuffers(n, renderbuffers);
+  }
 }
 
 static void _glGetFramebufferAttachmentParameteriv(GLenum target,
@@ -659,6 +682,7 @@ static void library_init() {
   epoxy_glCreateProgram = _glCreateProgram;
   epoxy_glCreateShader = _glCreateShader;
   epoxy_glDeleteFramebuffers = _glDeleteFramebuffers;
+  epoxy_glDeleteRenderbuffers = _glDeleteRenderbuffers;
   epoxy_glDeleteShader = _glDeleteShader;
   epoxy_glDeleteTextures = _glDeleteTextures;
   epoxy_glFramebufferRenderbuffer = _glFramebufferRenderbuffer;

engine/src/flutter/shell/platform/linux/testing/mock_epoxy.h

@@ -34,6 +34,16 @@ class MockEpoxy {
                GLint dstY1,
                GLbitfield mask,
                GLenum filter));
+  MOCK_METHOD(void,
+              glDeleteFramebuffers,
+              (GLsizei n, const GLuint* framebuffers));
+  MOCK_METHOD(void,
+              glDeleteRenderbuffers,
+              (GLsizei n, const GLuint* renderbuffers));
+  MOCK_METHOD(void, glDeleteTextures, (GLsizei n, const GLuint* textures));
+  MOCK_METHOD(void, glGenFramebuffers, (GLsizei n, GLuint* framebuffers));
+  MOCK_METHOD(void, glGenRenderbuffers, (GLsizei n, GLuint* renderbuffers));
+  MOCK_METHOD(void, glGenTextures, (GLsizei n, GLuint* textures));
   MOCK_METHOD(const GLubyte*, glGetString, (GLenum pname));
 };