cc: Adding support for RGBA_4444 tile textures

cc/resources/resource_provider.cc

Index: cc/resources/resource_provider.cc
diff --git a/cc/resources/resource_provider.cc b/cc/resources/resource_provider.cc
index 9779a546958441a5af186e05e316b4dcc795e1bd..fe0547277770fdbd1d82c50e6aa58e96373092e1 100644
--- a/cc/resources/resource_provider.cc
+++ b/cc/resources/resource_provider.cc
@@ -161,9 +161,12 @@ ResourceProvider::Child::~Child() {}
 
 scoped_ptr<ResourceProvider> ResourceProvider::Create(
     OutputSurface* output_surface,
-    int highp_threshold_min) {
+    int highp_threshold_min,
+    bool use_rgba_4444_textures) {
   scoped_ptr<ResourceProvider> resource_provider(
-      new ResourceProvider(output_surface, highp_threshold_min));
+      new ResourceProvider(output_surface,
+                           highp_threshold_min,
+                           use_rgba_4444_textures));
 
   bool success = false;
   if (resource_provider->Context3d()) {
@@ -670,7 +673,8 @@ ResourceProvider::ScopedWriteLockSoftware::~ScopedWriteLockSoftware() {
 }
 
 ResourceProvider::ResourceProvider(OutputSurface* output_surface,
-                                   int highp_threshold_min)
+                                   int highp_threshold_min,
+                                   bool use_rgba_4444_textures)
     : output_surface_(output_surface),
       lost_output_surface_(false),
       highp_threshold_min_(highp_threshold_min),
@@ -681,7 +685,8 @@ ResourceProvider::ResourceProvider(OutputSurface* output_surface,
       use_texture_usage_hint_(false),
       use_shallow_flush_(false),
       max_texture_size_(0),
-      best_texture_format_(0) {
+      best_texture_format_(0),
+      best_texture_type_(use_rgba_4444_textures ? RGBA_4444 : RGBA_8888) {
   DCHECK(output_surface_->HasClient());
 }
 
@@ -719,7 +724,10 @@ bool ResourceProvider::InitializeGL() {
   use_texture_usage_hint_ = caps.texture_usage;
 
   texture_uploader_ =
-      TextureUploader::Create(context3d, use_map_sub, use_shallow_flush_);
+      TextureUploader::Create(context3d,
+                              use_map_sub,
+                              use_shallow_flush_,
+                              best_texture_type_ == RGBA_4444);
   GLC(context3d, context3d->getIntegerv(GL_MAX_TEXTURE_SIZE,
                                         &max_texture_size_));
   best_texture_format_ = PlatformColor::BestTextureFormat(use_bgra);
@@ -975,9 +983,10 @@ void ResourceProvider::AcquirePixelBuffer(ResourceId id) {
     context3d->bindBuffer(
         GL_PIXEL_UNPACK_TRANSFER_BUFFER_CHROMIUM,
         resource->gl_pixel_buffer_id);
+    size_t bytes_per_pixel = (best_texture_type_ == RGBA_4444) ? 2 : 4;
     context3d->bufferData(
         GL_PIXEL_UNPACK_TRANSFER_BUFFER_CHROMIUM,
-        4 * resource->size.GetArea(),
+        bytes_per_pixel * resource->size.GetArea(),
         NULL,
         GL_DYNAMIC_DRAW);
     context3d->bindBuffer(GL_PIXEL_UNPACK_TRANSFER_BUFFER_CHROMIUM, 0);
@@ -1159,6 +1168,19 @@ void ResourceProvider::BeginSetPixels(ResourceId id) {
     context3d->beginQueryEXT(
         GL_ASYNC_PIXEL_UNPACK_COMPLETED_CHROMIUM,
         resource->gl_upload_query_id);
+    GLenum texture_data_type = GL_UNSIGNED_BYTE;
+    switch (best_texture_type_) {
+      case RGBA_4444:
+        texture_data_type = GL_UNSIGNED_SHORT_4_4_4_4;
+        break;
+      case RGBA_8888:
+        texture_data_type = GL_UNSIGNED_BYTE;
+        break;
+      default:
+        NOTREACHED();
+        break;
+    }
+
     if (allocate) {
       context3d->asyncTexImage2DCHROMIUM(GL_TEXTURE_2D,
                                          0, /* level */
@@ -1167,7 +1189,7 @@ void ResourceProvider::BeginSetPixels(ResourceId id) {
                                          resource->size.height(),
                                          0, /* border */
                                          resource->format,
-                                         GL_UNSIGNED_BYTE,
+                                         texture_data_type,
                                          NULL);
     } else {
       context3d->asyncTexSubImage2DCHROMIUM(GL_TEXTURE_2D,
@@ -1177,7 +1199,7 @@ void ResourceProvider::BeginSetPixels(ResourceId id) {
                                             resource->size.width(),
                                             resource->size.height(),
                                             resource->format,
-                                            GL_UNSIGNED_BYTE,
+                                            texture_data_type,
                                             NULL);
     }
     context3d->endQueryEXT(GL_ASYNC_PIXEL_UNPACK_COMPLETED_CHROMIUM);
@@ -1288,6 +1310,18 @@ void ResourceProvider::LazyAllocate(Resource* resource) {
                                               size.width(),
                                               size.height()));
   } else {
+    GLenum texture_data_type = GL_UNSIGNED_BYTE;
+    switch (best_texture_type_) {
+      case RGBA_4444:
+        texture_data_type = GL_UNSIGNED_SHORT_4_4_4_4;
+        break;
+      case RGBA_8888:
+        texture_data_type = GL_UNSIGNED_BYTE;
+        break;
+      default:
+        NOTREACHED();
+        break;
+    }
     GLC(context3d, context3d->texImage2D(GL_TEXTURE_2D,
                                          0,
                                          format,
@@ -1295,7 +1329,7 @@ void ResourceProvider::LazyAllocate(Resource* resource) {
                                          size.height(),
                                          0,
                                          format,
-                                         GL_UNSIGNED_BYTE,
+                                         texture_data_type,
                                          NULL));
   }
 }