Add a base mipmap level walkaround for Intel MacOSX

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 15680 matching lines @@
     }
   }
 
   GLenum compatibility_internal_format = internal_format;
   const CompressedFormatInfo* format_info =
       GetCompressedFormatInfo(internal_format);
   if (format_info != nullptr && !format_info->support_check(*feature_info_)) {
     compatibility_internal_format = format_info->decompressed_internal_format;
   }
 
+  GLint base_level = 0;

[Zhenyao Mo, 2016/08/25 18:06:55]

You should just use texture->base_level(), and no need to query the driver
later.

+  if (feature_info_->workarounds().reset_base_mipmap_level_before_texstorage) {
+    glGetTexParameteriv(target, GL_TEXTURE_BASE_LEVEL, &base_level);
+    if (base_level > 0)
+      glTexParameteri(target, GL_TEXTURE_BASE_LEVEL, 0);
+  }
   // TODO(zmo): We might need to emulate TexStorage using TexImage or
   // CompressedTexImage on Mac OSX where we expose ES3 APIs when the underlying
   // driver is lower than 4.2 and ARB_texture_storage extension doesn't exist.
   if (dimension == ContextState::k2D) {
     glTexStorage2DEXT(target, levels, compatibility_internal_format, width,
                       height);
   } else {
     glTexStorage3D(target, levels, compatibility_internal_format, width, height,
                    depth);
   }
+  if (feature_info_->workarounds().reset_base_mipmap_level_before_texstorage &&
+      base_level > 0)
+      glTexParameteri(target, GL_TEXTURE_BASE_LEVEL, base_level);
 
   {
     GLsizei level_width = width;
     GLsizei level_height = height;
     GLsizei level_depth = depth;
     GLenum adjusted_format =
         feature_info_->IsES3Enabled() ? internal_format : format;
     for (int ii = 0; ii < levels; ++ii) {
       if (target == GL_TEXTURE_CUBE_MAP) {
         for (int jj = 0; jj < 6; ++jj) {
@@ skipping 1973 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