gles2: Fix glDiscardFramebufferEXT

gpu/command_buffer/service/gles2_cmd_decoder.cc

 // Copyright (c) 2012 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 <limits.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
@@ skipping 5941 matching lines @@
     } else {
       if (!validators_->backbuffer_attachment.IsValid(attachment)) {
         LOCAL_SET_GL_ERROR_INVALID_ENUM(function_name, attachment,
                                         "attachments");
         return;
       }
     }
     validated_attachments[validated_count++] = attachment;
   }
   if (invalidate_depth && invalidate_stencil) {
-    validated_attachments[validated_count++] = GL_DEPTH_STENCIL_ATTACHMENT;
+    if (op != kFramebufferDiscard || gl_version_info().is_es3) {
+      validated_attachments[validated_count++] = GL_DEPTH_STENCIL_ATTACHMENT;
+    } else {
+      // DEPTH_STENCIL is not a valid token for glDiscardFramebufferEXT
+      validated_attachments[validated_count++] = GL_DEPTH_ATTACHMENT;
+      validated_attachments[validated_count++] = GL_STENCIL_ATTACHMENT;

[Zhenyao Mo, 2016/12/19 17:53:48]

It's easier to always split to DEPTH_ATTACHMENT and STENCIL_ATTACHMENT here,
because in ES3 DEPTH_STENCIL_ATTACHMENT is just an alias for DEPTH_ATTACHMENT +
STENCIL_ATTACHMENT.

[jbriance, 2016/12/19 19:40:45]

Done in patch set 3

+    }
   }
 
   // If the default framebuffer is bound but we are still rendering to an
   // FBO, translate attachment names that refer to default framebuffer
   // channels to corresponding framebuffer attachments.
   std::unique_ptr<GLenum[]> translated_attachments(new GLenum[validated_count]);
   for (GLsizei i = 0; i < validated_count; ++i) {
     GLenum attachment = validated_attachments[i];
     if (!framebuffer && GetBackbufferServiceId()) {
       switch (attachment) {
@@ skipping 13022 matching lines @@
 }
 
 // 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 "base/macros.h"
 #include "gpu/command_buffer/service/gles2_cmd_decoder_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu