Adjust workaround for mipmap-related OpenGL implementation bug on Mac OS X.

gpu/command_buffer/service/gles2_cmd_decoder.cc

 // Copyright (c) 2011 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 2990 matching lines @@
 
 void GLES2DecoderImpl::DoGenerateMipmap(GLenum target) {
   TextureManager::TextureInfo* info = GetTextureInfoForTarget(target);
   if (!info || !texture_manager()->MarkMipmapsGenerated(feature_info_, info)) {
     SetGLError(GL_INVALID_OPERATION,
                "glGenerateMipmaps: Can not generate mips for npot textures");
     return;
   }
   // Workaround for Mac driver bug. In the large scheme of things setting
   // glTexParamter twice for glGenerateMipmap is probably not a lage performance
-  // hit so there's probably no need to make this conditional.
-  glTexParameteri(target, GL_TEXTURE_MIN_FILTER, GL_NEAREST_MIPMAP_LINEAR);
+  // hit so there's probably no need to make this conditional. The bug appears
+  // to be that if the filtering mode is set to something that doesn't require
+  // mipmaps for rendering, or is never set to something other than the default,
+  // then glGenerateMipmap misbehaves.
+  glTexParameteri(target, GL_TEXTURE_MIN_FILTER, GL_NEAREST_MIPMAP_NEAREST);

[greggman, 2011/10/20 23:27:37]

It seems like there are 2 possibliies

1) The state needs to be GL_NEAREST_MIPMAP_NEAREST
2) The state needs to be dirty

If it's #2 this won't fix it in certain cases. That seems easy to test

genTex
bindTex
texParm(GL_NEAREST_MIPMAP_NEAREST
texImage2d(red
genMips
texImage2d(blue
genMips

should we test that?

[Ken Russell (switch to Gerrit), 2011/10/20 23:36:24]

I believe it's neither, but a third possibility: the filter mode needs to have
been changed from the default at least once, and also needs to be set to
something requiring mipmaps.

   glGenerateMipmapEXT(target);
   glTexParameteri(target, GL_TEXTURE_MIN_FILTER, info->min_filter());
 }
 
 bool GLES2DecoderImpl::GetHelper(
     GLenum pname, GLint* params, GLsizei* num_written) {
   DCHECK(num_written);
   if (gfx::GetGLImplementation() != gfx::kGLImplementationEGLGLES2) {
     switch (pname) {
     case GL_IMPLEMENTATION_COLOR_READ_FORMAT:
@@ skipping 4179 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