Optimize alpha software PictureDrawQuads.

cc/output/gl_renderer.cc

 // Copyright 2010 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/output/gl_renderer.h"
 
 #include <algorithm>
 #include <limits>
 #include <set>
 #include <string>
@@ skipping 19 matching lines @@
 #include "cc/quads/render_pass.h"
 #include "cc/quads/stream_video_draw_quad.h"
 #include "cc/quads/texture_draw_quad.h"
 #include "cc/resources/layer_quad.h"
 #include "cc/resources/scoped_resource.h"
 #include "cc/resources/sync_point_helper.h"
 #include "cc/trees/damage_tracker.h"
 #include "cc/trees/proxy.h"
 #include "cc/trees/single_thread_proxy.h"
 #include "gpu/GLES2/gl2extchromium.h"
+#include "skia/ext/opacity_draw_filter.h"
 #include "third_party/WebKit/public/platform/WebGraphicsContext3D.h"
 #include "third_party/khronos/GLES2/gl2.h"
 #include "third_party/khronos/GLES2/gl2ext.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "third_party/skia/include/core/SkColorFilter.h"
 #include "third_party/skia/include/core/SkSurface.h"
 #include "third_party/skia/include/gpu/GrContext.h"
 #include "third_party/skia/include/gpu/GrTexture.h"
 #include "third_party/skia/include/gpu/SkGpuDevice.h"
@@ skipping 1579 matching lines @@
       Context()->uniform1i(program->fragment_shader().sampler_location(), 0));
 
   SetShaderOpacity(quad->opacity(),
                    program->fragment_shader().alpha_location());
   DrawQuadGeometry(frame,
                    quad->quadTransform(),
                    quad->rect,
                    program->vertex_shader().matrix_location());
 }
 
 void GLRenderer::DrawPictureQuadDirectToBackbuffer(

[enne (OOO), 2013/08/28 20:08:42]

Can you not change this path?  I'm not sure I want to saddle Ganesh usage with
bug compatibility with WebView.

[aelias_OOO_until_Jul13, 2013/08/28 20:23:00]

OK, reverted.  The optimization could be eventually usable by Ganesh if tiling
is carefully disabled only when the requirements hold true, but we can cross
that bridge when we get to it.

     const DrawingFrame* frame,
     const PictureDrawQuad* quad) {
   DCHECK(CanUseSkiaGPUBackend());
-  DCHECK_EQ(quad->opacity(), 1.f) << "Need to composite to a bitmap or a "
-                                     "render surface for non-1 opacity quads";
 
   // TODO(enne): This should be done more lazily / efficiently.
   gr_context_->resetContext();
 
   // Reset the canvas matrix to identity because the clip rect is in target
   // space.
   SkMatrix sk_identity;
   sk_identity.setIdentity();
   sk_canvas_->setMatrix(sk_identity);
 
   if (is_scissor_enabled_) {
     sk_canvas_->clipRect(gfx::RectToSkRect(scissor_rect_),
                          SkRegion::kReplace_Op);
   } else {
     sk_canvas_->clipRect(gfx::RectToSkRect(client_->DeviceViewport()),
                          SkRegion::kReplace_Op);
   }
 
   gfx::Transform contents_device_transform = frame->window_matrix *
     frame->projection_matrix * quad->quadTransform();
   contents_device_transform.Translate(quad->rect.x(),
                                       quad->rect.y());
   contents_device_transform.FlattenTo2d();
   SkMatrix sk_device_matrix;
   gfx::TransformToFlattenedSkMatrix(contents_device_transform,
                                     &sk_device_matrix);
   sk_canvas_->setMatrix(sk_device_matrix);
 
+  if (quad->opacity() != 1.0f) {
+    DCHECK(!sk_canvas_->getDrawFilter());
+    sk_canvas_->setDrawFilter(
+        new skia::OpacityDrawFilter(quad->opacity(), false));
+  }
+
   quad->picture_pile->RasterDirect(
       sk_canvas_.get(), quad->content_rect, quad->contents_scale, NULL);
 
   // Flush any drawing buffers that have been deferred.
   sk_canvas_->flush();
 
+  sk_canvas_->setDrawFilter(NULL);
+
   // TODO(enne): This should be done more lazily / efficiently.
   ReinitializeGLState();
 }
 
 void GLRenderer::DrawPictureQuad(const DrawingFrame* frame,
                                  const PictureDrawQuad* quad) {
   if (quad->can_draw_direct_to_backbuffer && CanUseSkiaGPUBackend()) {
     DrawPictureQuadDirectToBackbuffer(frame, quad);
     return;
   }
@@ skipping 1467 matching lines @@
   std::string unique_context_name = base::StringPrintf(
       "%s-Offscreen-%p",
       Settings().compositor_name.c_str(),
       context_);
   resource_provider()->offscreen_context_provider()->Context3d()->
     pushGroupMarkerEXT(unique_context_name.c_str());
 }
 
 
 }  // namespace cc