cc: Adding ETC1 support to UIResourceBitmap and ResourceProvider

cc/resources/resource_provider.cc

 // Copyright 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 "cc/resources/resource_provider.h"
 
 #include <algorithm>
 #include <limits>
 
 #include "base/containers/hash_tables.h"
@@ skipping 29 matching lines @@
   GLenum storage_format = GL_RGBA8_OES;
   switch (format) {
     case RGBA_8888:
       break;
     case BGRA_8888:
       storage_format = GL_BGRA8_EXT;
       break;
     case RGBA_4444:
     case LUMINANCE_8:
     case RGB_565:
+    case ETC1:
       NOTREACHED();
       break;
   }
 
   return storage_format;
 }
 
 bool IsFormatSupportedForStorage(ResourceFormat format) {
   switch (format) {
     case RGBA_8888:
     case BGRA_8888:
       return true;
     case RGBA_4444:
     case LUMINANCE_8:
     case RGB_565:
+    case ETC1:
       return false;
   }
   return false;
 }
 
 class ScopedSetActiveTexture {
  public:
   ScopedSetActiveTexture(WebGraphicsContext3D* context3d, GLenum unit)
       : context3d_(context3d), unit_(unit) {
     DCHECK_EQ(GL_TEXTURE0, ResourceProvider::GetActiveTextureUnit(context3d_));
@@ skipping 756 matching lines @@
   default_resource_type_ = GLTexture;
 
   const ContextProvider::Capabilities& caps =
       output_surface_->context_provider()->ContextCapabilities();
 
   bool use_map_sub = caps.map_sub;
   bool use_bgra = caps.texture_format_bgra8888;
   use_texture_storage_ext_ = caps.texture_storage;
   use_shallow_flush_ = caps.shallow_flush;
   use_texture_usage_hint_ = caps.texture_usage;
+  use_compressed_texture_etc1_ = caps.texture_format_etc1;
 
   texture_uploader_ =
       TextureUploader::Create(context3d, use_map_sub, use_shallow_flush_);
   GLC(context3d, context3d->getIntegerv(GL_MAX_TEXTURE_SIZE,
                                         &max_texture_size_));
   best_texture_format_ = PlatformColor::BestTextureFormat(use_bgra);
 
   return true;
 }
 
@@ skipping 406 matching lines @@
 
   if (!to_return.empty())
     child_info->return_callback.Run(to_return);
 }
 
 void ResourceProvider::AcquirePixelBuffer(ResourceId id) {
   Resource* resource = GetResource(id);
   DCHECK(!resource->external);
   DCHECK_EQ(resource->exported_count, 0);
   DCHECK(!resource->image_id);
+  DCHECK_NE(ETC1, resource->format);
 
   if (resource->type == GLTexture) {
     WebGraphicsContext3D* context3d = Context3d();
     DCHECK(context3d);
     if (!resource->gl_pixel_buffer_id)
       resource->gl_pixel_buffer_id = context3d->createBuffer();
     context3d->bindBuffer(
         GL_PIXEL_UNPACK_TRANSFER_BUFFER_CHROMIUM,
         resource->gl_pixel_buffer_id);
     unsigned bytes_per_pixel = BytesPerPixel(resource->format);
@@ skipping 312 matching lines @@
   ResourceFormat format = resource->format;
   GLC(context3d, context3d->bindTexture(GL_TEXTURE_2D, resource->gl_id));
   if (use_texture_storage_ext_ && IsFormatSupportedForStorage(format)) {
     GLenum storage_format = TextureToStorageFormat(format);
     GLC(context3d, context3d->texStorage2DEXT(GL_TEXTURE_2D,
                                               1,
                                               storage_format,
                                               size.width(),
                                               size.height()));
   } else {
-    GLC(context3d, context3d->texImage2D(GL_TEXTURE_2D,
-                                         0,
-                                         GLInternalFormat(format),
-                                         size.width(),
-                                         size.height(),
-                                         0,
-                                         GLDataFormat(format),
-                                         GLDataType(format),
-                                         NULL));
+    if (format == ETC1) {
+      DCHECK(use_compressed_texture_etc1_);
+      DCHECK_EQ(0, size.width() % 4);
+      DCHECK_EQ(0, size.height() % 4);
+      GLC(context3d,
+          context3d->compressedTexImage2D(
+              GL_TEXTURE_2D,
+              0,
+              GLInternalFormat(format),
+              size.width(),
+              size.height(),
+              0,
+              cc::Resource::MemorySizeBytes(size, format),
+              NULL));

[no sievers, 2013/10/23 22:49:59]

I don't think glCompressedTexImage2D() supports passing NULL here to preallocate
the storage per the spec. 
The service side seems to handle null pointers (but I did not look at the
cmdbuffer code in the middle). It allocates a buffer set to 0. But even then, if
that doesn't decode properly, this call could still fail (spec: 'If the
compressed image is not encoded according to the defined image format, the
results of the call are
undefined.').

Maybe should just do nothing herefor ETC1?

[powei, 2013/10/23 23:25:58]

Done.  Thanks for catching that.

+    } else {
+      GLC(context3d,
+          context3d->texImage2D(GL_TEXTURE_2D,
+                                0,
+                                GLInternalFormat(format),
+                                size.width(),
+                                size.height(),
+                                0,
+                                GLDataFormat(format),
+                                GLDataType(format),
+                                NULL));
+    }
   }
 }
 
 void ResourceProvider::EnableReadLockFences(ResourceProvider::ResourceId id,
                                             bool enable) {
   Resource* resource = GetResource(id);
   resource->enable_read_lock_fences = enable;
 }
 
 void ResourceProvider::AcquireImage(ResourceId id) {
@@ skipping 97 matching lines @@
   context->getIntegerv(GL_ACTIVE_TEXTURE, &active_unit);
   return active_unit;
 }
 
 WebKit::WebGraphicsContext3D* ResourceProvider::Context3d() const {
   ContextProvider* context_provider = output_surface_->context_provider();
   return context_provider ? context_provider->Context3d() : NULL;
 }
 
 }  // namespace cc