Turn on seamless cubemap by default on Desktop GL for ES3.

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 2724 matching lines @@
       LOG(ERROR) << "Underlying driver does not support ES3.";
       Destroy(true);
       return false;
     }
     feature_info_->EnableES3Validators();
     set_unsafe_es3_apis_enabled(true);
 
     frag_depth_explicitly_enabled_ = true;
     draw_buffers_explicitly_enabled_ = true;
     // TODO(zmo): Look into shader_texture_lod_explicitly_enabled_ situation.
+
+    // TEXTURE_CUBE_MAP_SEAMLESS is available on Desktop GL 3.2 or above.
+    // ES3 requires it to be always supported.
+    // We don't support ES3 on Desktop GL lower than 3.2.
+    if (!feature_info_->gl_version_info().BehavesLikeGLES()) {
+      glEnable(GL_TEXTURE_CUBE_MAP_SEAMLESS);
+    }

[piman, 2016/03/25 17:01:04]

Can you remove this? The code below will take care of it, right?

[Zhenyao Mo, 2016/03/25 17:17:29]

Ah, nasty.  I thought I deleted already.

   }
 
   state_.attrib_values.resize(group_->max_vertex_attribs());
   vertex_array_manager_.reset(new VertexArrayManager());
 
   GLuint default_vertex_attrib_service_id = 0;
   if (features().native_vertex_array_object) {
     glGenVertexArraysOES(1, &default_vertex_attrib_service_id);
     glBindVertexArrayOES(default_vertex_attrib_service_id);
   }
@@ skipping 256 matching lines @@
   // variable in fragment shaders.
   if (!feature_info_->gl_version_info().BehavesLikeGLES()) {
     glEnable(GL_VERTEX_PROGRAM_POINT_SIZE);
     glEnable(GL_POINT_SPRITE);
   } else if (feature_info_->gl_version_info().is_desktop_core_profile) {
     // The desktop core profile changed how program point size mode is
     // enabled.
     glEnable(GL_PROGRAM_POINT_SIZE);
   }
 
+  // ES3 requires seamless cubemap. ES2 does not.
+  // However, when ES2 is implemented on top of DX11, seamless cubemap is
+  // always enabled and there is no way to disable it.
+  // Therefore, it seems OK to also always enable it on top of Desktop GL for
+  // both ES2 and ES3 contexts.
+  if (feature_info_->gl_version_info().IsAtLeastGL(3, 2)) {
+    glEnable(GL_TEXTURE_CUBE_MAP_SEAMLESS);
+  }
+
   has_robustness_extension_ =
       context->HasExtension("GL_ARB_robustness") ||
       context->HasExtension("GL_KHR_robustness") ||
       context->HasExtension("GL_EXT_robustness");
 
   if (!InitializeShaderTranslator()) {
     return false;
   }
 
   GLint viewport_params[4] = { 0 };
@@ skipping 13302 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