cc: Adding support for RGBA_4444 tile textures

cc/resources/resource_provider.h

Index: cc/resources/resource_provider.h
diff --git a/cc/resources/resource_provider.h b/cc/resources/resource_provider.h
index 412c92b377ba27815d68bef2d9235288e5633d36..83c3a76863993f7469a4f2681796c0e73e5e8ea3 100644
--- a/cc/resources/resource_provider.h
+++ b/cc/resources/resource_provider.h
@@ -52,9 +52,14 @@ class CC_EXPORT ResourceProvider {
     GLTexture = 1,
     Bitmap,
   };
+  enum TextureType {

[epennerAtGoogle, 2013/09/06 03:24:44]

I'm interested in what others think here, but I was thinking this could replace
both the format and and type parameters throughout resource provider. Then, only
when we invoke GL, we can choose the GL format and GL type based on this Enum.

[reveman, 2013/09/06 03:47:15]

Maybe OK to just use the internal formats defined by standard GL. ie. GL_RGBA8,
GL_RGBA4, GL_BGRA and just translate those to supported
internalformat,pixel-data-format,pixel-data-type. If we think that might be
confusing then new enum values such as these are fine with me.

Whatever we do, it should replace format and and type parameters throughout RP
as you already mentioned.

+    RGBA_8888,
+    RGBA_4444,

[epennerAtGoogle, 2013/09/06 03:24:44]

Do we need BGRA_8888 also? The idea to use this enum is that it would
encapsulate _both_ the format and type parameters, and I believe we have
BGRA_EXT used as a format elsewhere.

+  };
 
   static scoped_ptr<ResourceProvider> Create(OutputSurface* output_surface,
-                                             int highp_threshold_min);
+                                             int highp_threshold_min,
+                                             bool use_rgba_4444_textures);

[epennerAtGoogle, 2013/09/06 03:24:44]

How about TextureType best_texture_type, and no boolean?

 
   virtual ~ResourceProvider();
 
@@ -65,6 +70,7 @@ class CC_EXPORT ResourceProvider {
 
   int max_texture_size() const { return max_texture_size_; }
   GLenum best_texture_format() const { return best_texture_format_; }

[epennerAtGoogle, 2013/09/06 03:24:44]

I was hoping we could get rid of the GLenum completely here. That would involve
changing any code that calls this to respect the Enum. The problem with
returning the GLenum is that it is RGBA for both 4444 and 8888.

+  TextureType best_texture_type() const { return best_texture_type_; }
   size_t num_resources() const { return resources_.size(); }
 
   // Checks whether a resource is in use by a consumer.
@@ -381,8 +387,9 @@ class CC_EXPORT ResourceProvider {
            resource->read_lock_fence->HasPassed();
   }
 
-  explicit ResourceProvider(OutputSurface* output_surface,
-                            int highp_threshold_min);
+  ResourceProvider(OutputSurface* output_surface,
+                   int highp_threshold_min,
+                   bool use_rgba_4444_textures);
 
   void CleanUpGLIfNeeded();
 
@@ -434,6 +441,7 @@ class CC_EXPORT ResourceProvider {
   scoped_ptr<TextureUploader> texture_uploader_;
   int max_texture_size_;
   GLenum best_texture_format_;
+  TextureType best_texture_type_;
 
   base::ThreadChecker thread_checker_;