Clear the copy of the offscreen texture used by shared contexts after the DEP...

gpu/command_buffer/service/gles2_cmd_decoder.cc

 // Copyright (c) 2009 The Chromium 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 "gpu/command_buffer/service/gles2_cmd_decoder.h"
 
 #include <stdio.h>
 
 #include <algorithm>
 #include <list>
@@ skipping 1741 matching lines @@
     return offscreen_target_color_texture_->size();
   } else {
     return context_->GetSize();
   }
 }
 
 bool GLES2DecoderImpl::UpdateOffscreenFrameBufferSize() {
   if (offscreen_target_color_texture_->size() == pending_offscreen_size_)
     return true;
 
-  if (parent_) {
-    // Create the saved offscreen color texture (only accessible to parent).
-    offscreen_saved_color_texture_->AllocateStorage(pending_offscreen_size_);
-
-    // Attach the saved offscreen color texture to a frame buffer so we can
-    // clear it with glClear.
-    offscreen_target_frame_buffer_->AttachRenderTexture(
-        offscreen_saved_color_texture_.get());
-    if (offscreen_target_frame_buffer_->CheckStatus() !=
-        GL_FRAMEBUFFER_COMPLETE) {
-      return false;
-    }
-
-    // TODO(apatrick): Fix this once ANGLE supports shared contexts.
-    // Clear the saved offscreen color texture. Use default GL context
-    // to ensure clear is not affected by client set state.
-    if (gfx::GetGLImplementation() != gfx::kGLImplementationEGLGLES2) {
-      ScopedDefaultGLContext scoped_context(this);
-      glBindFramebufferEXT(GL_FRAMEBUFFER,
-                           offscreen_target_frame_buffer_->id());
-      glClear(GL_COLOR_BUFFER_BIT);
-      glBindFramebufferEXT(GL_FRAMEBUFFER, 0);
-
-      if (glGetError() != GL_NO_ERROR)
-        return false;
-    }
-  }
-
   // Reallocate the offscreen target buffers.
   if (!offscreen_target_color_texture_->AllocateStorage(
       pending_offscreen_size_)) {
     return false;
   }
 
   if (gfx::GetGLImplementation() == gfx::kGLImplementationEGLGLES2) {
     // ANGLE only allows 16-bit depth buffers to be requested. As it happens,
     // it creates a 24-bit depth buffer behind the scenes.
     // TODO(apatrick): Attempt to use a packed 24/8 depth stencil buffer here if
@@ skipping 42 matching lines @@
     glBindFramebufferEXT(GL_FRAMEBUFFER,
                          offscreen_target_frame_buffer_->id());
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
     glBindFramebufferEXT(GL_FRAMEBUFFER, 0);
 
     if (glGetError() != GL_NO_ERROR)
       return false;
   }
 
   if (parent_) {
-    // Create the saved offscreen color texture (only accessible to parent).
+    // Adjust the saved offscreen color texture (only accessible to parent).
     offscreen_saved_color_texture_->AllocateStorage(pending_offscreen_size_);
 
     // Update the info about the offscreen saved color texture in the parent.
     // The reference to the parent is a weak pointer and will become null if the
     // parent is later destroyed.
     GLuint service_id = offscreen_saved_color_texture_->id();
     GLuint client_id;
     CHECK(parent_->texture_manager()->GetClientId(service_id, &client_id));
     TextureManager::TextureInfo* info = parent_->GetTextureInfo(client_id);
     DCHECK(info);
 
     texture_manager()->SetLevelInfo(
         info,
         GL_TEXTURE_2D,
         0,  // level
         GL_RGBA,
         pending_offscreen_size_.width(),
         pending_offscreen_size_.height(),
         1,  // depth
         0,  // border
         GL_RGBA,
         GL_UNSIGNED_BYTE);
   }
 
+  // Attach the saved offscreen color texture to a frame buffer so we can
+  // clear it with glClear.
+  offscreen_target_frame_buffer_->AttachRenderTexture(
+      offscreen_saved_color_texture_.get());
+  if (offscreen_target_frame_buffer_->CheckStatus() !=
+      GL_FRAMEBUFFER_COMPLETE) {
+    return false;
+  }
+
+  // TODO(apatrick): Fix this once ANGLE supports shared contexts.
+  // Clear the saved offscreen color texture. Use default GL context
+  // to ensure clear is not affected by client set state.
+  if (gfx::GetGLImplementation() != gfx::kGLImplementationEGLGLES2) {
+    ScopedDefaultGLContext scoped_context(this);
+    glBindFramebufferEXT(GL_FRAMEBUFFER,
+                         offscreen_target_frame_buffer_->id());
+    glClear(GL_COLOR_BUFFER_BIT);
+    glBindFramebufferEXT(GL_FRAMEBUFFER, 0);
+
+    if (glGetError() != GL_NO_ERROR)
+      return false;
+  }
+
+  // Re-attach the offscreen render texture to the target frame buffer.
+  offscreen_target_frame_buffer_->AttachRenderTexture(
+      offscreen_target_color_texture_.get());
+
   return true;
 }
 
 void GLES2DecoderImpl::SetSwapBuffersCallback(Callback0::Type* callback) {
   swap_buffers_callback_.reset(callback);
 }
 
 void GLES2DecoderImpl::Destroy() {
   if (context_) {
     MakeCurrent();
@@ skipping 2881 matching lines @@
   return error::kNoError;
 }
 
 // Include the auto-generated part of this file. We split this because it means
 // we can easily edit the non-auto generated parts right here in this file
 // instead of having to edit some template or the code generator.
 #include "gpu/command_buffer/service/gles2_cmd_decoder_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu