cc: Adding support for RGBA_4444 tile textures

cc/scheduler/texture_uploader.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/scheduler/texture_uploader.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/debug/alias.h"
@@ skipping 59 matching lines @@
 unsigned TextureUploader::Query::Value() {
   if (!has_value_) {
     context_->getQueryObjectuivEXT(query_id_, GL_QUERY_RESULT_EXT, &value_);
     has_value_ = true;
   }
   return value_;
 }
 
 TextureUploader::TextureUploader(WebKit::WebGraphicsContext3D* context,
                                  bool use_map_tex_sub_image,
-                                 bool use_shallow_flush)
+                                 bool use_shallow_flush,
+                                 bool use_16_bit_textures)
     : context_(context),
       num_blocking_texture_uploads_(0),
       use_map_tex_sub_image_(use_map_tex_sub_image),
       sub_image_size_(0),
       use_shallow_flush_(use_shallow_flush),
-      num_texture_uploads_since_last_flush_(0) {
+      num_texture_uploads_since_last_flush_(0),
+      use_16_bit_textures_(use_16_bit_textures) {
   for (size_t i = kUploadHistorySizeInitial; i > 0; i--)
     textures_per_second_history_.insert(kDefaultEstimatedTexturesPerSecond);
 }
 
 TextureUploader::~TextureUploader() {}
 
 size_t TextureUploader::NumBlockingUploads() {
   ProcessQueries();
   return num_blocking_texture_uploads_;
 }
@@ skipping 103 matching lines @@
   base::debug::Alias(&image_rect_width);
   base::debug::Alias(&image_rect_height);
   base::debug::Alias(&dest_offset_x);
   base::debug::Alias(&dest_offset_y);
   TRACE_EVENT0("cc", "TextureUploader::UploadWithTexSubImage");
 
   // Offset from image-rect to source-rect.
   gfx::Vector2d offset(source_rect.origin() - image_rect.origin());
 
   const uint8* pixel_source;
-  unsigned int bytes_per_pixel = Resource::BytesPerPixel(format);
+  unsigned int bytes_per_pixel = Resource::BytesPerPixel(format,
+                                                         use_16_bit_textures_);
+  // TODO(kaanb): anything to do to GL_UNPACK_ALIGNMENT for 16_bit?

[Sami, 2013/09/05 14:13:26]

Yes, it needs to be set to 2 bytes. Otherwise odd-width bitmaps will look, well,
odd :) The alternative is to allocate our 16 bit source bitmaps with 4-byte
aligned strides. I'm not sure if Skia supports that.

[kaanb, 2013/09/06 02:05:54]

Silly question, how and where should it be set?

   // Use 4-byte row alignment (OpenGL default) for upload performance.
   // Assuming that GL_UNPACK_ALIGNMENT has not changed from default.
   unsigned int upload_image_stride =
-      RoundUp(bytes_per_pixel * source_rect.width(), 4u);
+      RoundUp(bytes_per_pixel * source_rect.width(), bytes_per_pixel);
 
   if (upload_image_stride == image_rect.width() * bytes_per_pixel &&
       !offset.x()) {
     pixel_source = &image[image_rect.width() * bytes_per_pixel * offset.y()];
   } else {
     size_t needed_size = upload_image_stride * source_rect.height();
     if (sub_image_size_ < needed_size) {
       sub_image_.reset(new uint8[needed_size]);
       sub_image_size_ = needed_size;
     }
     // Strides not equal, so do a row-by-row memcpy from the
     // paint results into a temp buffer for uploading.
     for (int row = 0; row < source_rect.height(); ++row)
       memcpy(&sub_image_[upload_image_stride * row],
              &image[bytes_per_pixel *
                  (offset.x() + (offset.y() + row) * image_rect.width())],
              source_rect.width() * bytes_per_pixel);
 
     pixel_source = &sub_image_[0];
   }
 
+  GLenum texture_data_type = use_16_bit_textures_
+      ? GL_UNSIGNED_SHORT_4_4_4_4 : GL_UNSIGNED_BYTE;
   context_->texSubImage2D(GL_TEXTURE_2D,
                           0,
                           dest_offset.x(),
                           dest_offset.y(),
                           source_rect.width(),
                           source_rect.height(),
                           format,
-                          GL_UNSIGNED_BYTE,
+                          texture_data_type,
                           pixel_source);
 }
 
 void TextureUploader::UploadWithMapTexSubImage(const uint8* image,
                                                gfx::Rect image_rect,
                                                gfx::Rect source_rect,
                                                gfx::Vector2d dest_offset,
                                                GLenum format) {
   // Instrumentation to debug issue 156107
   int source_rect_x = source_rect.x();
@@ skipping 16 matching lines @@
   base::debug::Alias(&image_rect_width);
   base::debug::Alias(&image_rect_height);
   base::debug::Alias(&dest_offset_x);
   base::debug::Alias(&dest_offset_y);
 
   TRACE_EVENT0("cc", "TextureUploader::UploadWithMapTexSubImage");
 
   // Offset from image-rect to source-rect.
   gfx::Vector2d offset(source_rect.origin() - image_rect.origin());
 
-  unsigned int bytes_per_pixel = Resource::BytesPerPixel(format);
+  unsigned int bytes_per_pixel = Resource::BytesPerPixel(format,
+                                                         use_16_bit_textures_);
+  // TODO(kaanb): anything to do to GL_UNPACK_ALIGNMENT for 16 bit?
   // Use 4-byte row alignment (OpenGL default) for upload performance.
   // Assuming that GL_UNPACK_ALIGNMENT has not changed from default.
   unsigned int upload_image_stride =
-      RoundUp(bytes_per_pixel * source_rect.width(), 4u);
+      RoundUp(bytes_per_pixel * source_rect.width(), bytes_per_pixel);
 
+  GLenum texture_data_type = use_16_bit_textures_
+      ? GL_UNSIGNED_SHORT_4_4_4_4 : GL_UNSIGNED_BYTE;
   // Upload tile data via a mapped transfer buffer
   uint8* pixel_dest = static_cast<uint8*>(
       context_->mapTexSubImage2DCHROMIUM(GL_TEXTURE_2D,
                                          0,
                                          dest_offset.x(),
                                          dest_offset.y(),
                                          source_rect.width(),
                                          source_rect.height(),
                                          format,
-                                         GL_UNSIGNED_BYTE,
+                                         texture_data_type,
                                          GL_WRITE_ONLY));
 
   if (!pixel_dest) {
     UploadWithTexSubImage(image, image_rect, source_rect, dest_offset, format);
     return;
   }
 
   if (upload_image_stride == image_rect.width() * bytes_per_pixel &&
       !offset.x()) {
     memcpy(pixel_dest,
@@ skipping 35 matching lines @@
       textures_per_second_history_.erase(textures_per_second_history_.begin());
       textures_per_second_history_.erase(--textures_per_second_history_.end());
     }
     textures_per_second_history_.insert(textures_per_second);
 
     available_queries_.push_back(pending_queries_.take_front());
   }
 }
 
 }  // namespace cc