Enables GL_OES_standard_derivatives

Note: With this CL standard derivaties will unfortunately be accessable by
WebGL.  Another CL will be coming ASAP that fixes this.

TEST=unit tests
BUG=none

Review URL: http://codereview.chromium.org/3446008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@59859 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 23 insertions, 4 deletions

diff --git a/gpu/command_buffer/service/context_group.cc b/gpu/command_buffer/service/context_group.cc
index b4737ed..a09f041 100644
--- a/gpu/command_buffer/service/context_group.cc
+++ b/gpu/command_buffer/service/context_group.cc
@@ -95,6 +95,10 @@ bool ContextGroup::Initialize() {
 
   // Check if we should support GL_OES_packed_depth_stencil and/or
   // GL_GOOGLE_depth_texture.
+  // NOTE: GL_OES_depth_texture requires support for depth
+  // cubemaps. GL_ARB_depth_texture requires other features that
+  // GL_OES_packed_depth_stencil does not provide. Therefore we made up
+  // GL_GOOGLE_depth_texture.
   bool enable_depth_texture = false;
   if (strstr(extensions, "GL_ARB_depth_texture") ||
       strstr(extensions, "GL_OES_depth_texture")) {
@@ -212,6 +216,12 @@ bool ContextGroup::Initialize() {
     validators_.render_buffer_format.AddValue(GL_DEPTH_COMPONENT24);
   }
 
+  if (strstr(extensions, "GL_OES_standard_derivatives") ||
+      gfx::GetGLImplementation() == gfx::kGLImplementationDesktopGL) {
+    AddExtensionString("GL_OES_standard_derivatives");
+    extension_flags_.oes_standard_derivatives = true;
+  }
+
   // TODO(gman): Add support for these extensions.
   //     GL_OES_depth32
   //     GL_OES_element_index_uint
diff --git a/gpu/command_buffer/service/context_group.h b/gpu/command_buffer/service/context_group.h
index 77b1c7a..e48cacd 100644
--- a/gpu/command_buffer/service/context_group.h
+++ b/gpu/command_buffer/service/context_group.h
@@ -32,10 +32,12 @@ class ContextGroup {
  public:
   struct ExtensionFlags {
     ExtensionFlags()
-        : ext_framebuffer_multisample(false) {
+        : ext_framebuffer_multisample(false),
+          oes_standard_derivatives(false) {
     }
 
     bool ext_framebuffer_multisample;
+    bool oes_standard_derivatives;
   };
 
   ContextGroup();
diff --git a/gpu/command_buffer/service/context_group_unittest.cc b/gpu/command_buffer/service/context_group_unittest.cc
index 49efb3a..4384ea6 100644
--- a/gpu/command_buffer/service/context_group_unittest.cc
+++ b/gpu/command_buffer/service/context_group_unittest.cc
@@ -68,6 +68,7 @@ TEST_F(ContextGroupTest, Basic) {
   EXPECT_TRUE(group_.program_manager() == NULL);
   EXPECT_TRUE(group_.shader_manager() == NULL);
   EXPECT_FALSE(group_.extension_flags().ext_framebuffer_multisample);
+  EXPECT_FALSE(group_.extension_flags().oes_standard_derivatives);
 }
 
 TEST_F(ContextGroupTest, InitializeNoExtensions) {
@@ -376,6 +377,13 @@ TEST_F(ContextGroupTest, InitializeOES_depth24) {
       GL_DEPTH_COMPONENT24));
 }
 
+TEST_F(ContextGroupTest, InitializeOES_standard_derivatives) {
+  SetupInitExpectations("GL_OES_standard_derivatives");
+  group_.Initialize();
+  EXPECT_THAT(group_.extensions(), HasSubstr("GL_OES_standard_derivatives"));
+  EXPECT_TRUE(group_.extension_flags().oes_standard_derivatives);
+}
+
 }  // namespace gles2
 }  // namespace gpu
 
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index b94d92a..139e1af 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -1654,9 +1654,8 @@ bool GLES2DecoderImpl::Initialize(gfx::GLContext* context,
     resources.MaxFragmentUniformVectors =
         group_->max_fragment_uniform_vectors();
     resources.MaxDrawBuffers = 1;
-    // TODO(alokp): Figure out if OES_standard_derivatives extension is
-    // available.
-    resources.OES_standard_derivatives = 0;
+    resources.OES_standard_derivatives =
+        group_->extension_flags().oes_standard_derivatives ? 1 : 0;
     vertex_translator_.reset(new ShaderTranslator);
     if (!vertex_translator_->Init(EShLangVertex, &resources)) {
         DLOG(ERROR) << "Could not initialize vertex shader translator.";