Mac Overlays: Allow multiple overlays with sandwich strategy

cc/output/overlay_strategy_common.cc

 // Copyright 2015 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/overlay_strategy_common.h"
 
 #include <limits>
 
 #include "cc/quads/io_surface_draw_quad.h"
 #include "cc/quads/solid_color_draw_quad.h"
@@ skipping 15 matching lines @@
 }
 
 bool OverlayStrategyCommon::Attempt(RenderPassList* render_passes_in_draw_order,
                                     OverlayCandidateList* candidate_list,
                                     float device_scale_factor) {
   if (!capability_checker_)
     return false;
   RenderPass* root_render_pass = render_passes_in_draw_order->back();
   DCHECK(root_render_pass);
 
+  // Add our primary surface.
+  OverlayCandidate main_image;
+  main_image.display_rect = root_render_pass->output_rect;
+  DCHECK(candidate_list->empty());
+  candidate_list->push_back(main_image);
+
+  bool success = false;

[ccameron, 2015/09/08 17:16:06]

Maybe change "success" name to "created_overlay" (cause it's successful to have
none, after all).

[Andre, 2015/09/08 17:30:03]

Done.

   QuadList& quad_list = root_render_pass->quad_list;
-  for (auto it = quad_list.begin(); it != quad_list.end(); ++it) {
+  for (auto it = quad_list.begin(); it != quad_list.end();) {
     OverlayCandidate candidate;
-    const DrawQuad* draw_quad = *it;
-    if (IsOverlayQuad(draw_quad) &&
-        GetCandidateQuadInfo(*draw_quad, &candidate) &&
-        delegate_->TryOverlay(capability_checker_, render_passes_in_draw_order,
-                              candidate_list, candidate, it,
-                              device_scale_factor))
-      return true;
+    if (!GetCandidateQuadInfo(**it, &candidate)) {
+      ++it;
+      continue;
+    }
+
+    OverlayResult result = delegate_->TryOverlay(
+        capability_checker_, render_passes_in_draw_order, candidate_list,
+        candidate, &it, device_scale_factor);
+    switch (result) {
+      case DID_NOT_CREATE_OVERLAY:
+        ++it;
+        break;
+      case CREATED_OVERLAY_STOP_LOOKING:
+        return true;
+      case CREATED_OVERLAY_KEEP_LOOKING:
+        success = true;
+        break;
+    }
   }
-  return false;
-}
 
-bool OverlayStrategyCommon::IsOverlayQuad(const DrawQuad* draw_quad) {
-  switch (draw_quad->material) {
-    case DrawQuad::TEXTURE_CONTENT:
-      return TextureDrawQuad::MaterialCast(draw_quad)->allow_overlay();
-    case DrawQuad::STREAM_VIDEO_CONTENT:
-      return StreamVideoDrawQuad::MaterialCast(draw_quad)->allow_overlay();
-    case DrawQuad::IO_SURFACE_CONTENT:
-      return IOSurfaceDrawQuad::MaterialCast(draw_quad)->allow_overlay;
-    default:
-      return false;
+  if (!success) {
+    DCHECK_EQ(1u, candidate_list->size());
+    candidate_list->clear();
   }
+
+  return success;
 }
 
 // static
 bool OverlayStrategyCommon::IsInvisibleQuad(const DrawQuad* draw_quad) {
   if (draw_quad->material == DrawQuad::SOLID_COLOR) {
     const SolidColorDrawQuad* solid_quad =
         SolidColorDrawQuad::MaterialCast(draw_quad);
     SkColor color = solid_quad->color;
     float opacity = solid_quad->shared_quad_state->opacity;
     float alpha = (SkColorGetA(color) * (1.0f / 255.0f)) * opacity;
@@ skipping 78 matching lines @@
 
 bool OverlayStrategyCommon::GetCandidateQuadInfo(const DrawQuad& draw_quad,
                                                  OverlayCandidate* quad_info) {
   // All quad checks.
   if (draw_quad.needs_blending || draw_quad.shared_quad_state->opacity != 1.f ||
       draw_quad.shared_quad_state->blend_mode != SkXfermode::kSrcOver_Mode)
     return false;
 
   switch (draw_quad.material) {
     case DrawQuad::TEXTURE_CONTENT: {
       auto* quad = TextureDrawQuad::MaterialCast(&draw_quad);

[ccameron, 2015/09/08 17:16:05]

Maybe move the allow_overlay() into GetTextureQuadInfo, GetVideoQuadInfo, and
GetIOSurfaceQuadInfo?

[Andre, 2015/09/08 17:30:03]

Done.

-      if (!GetTextureQuadInfo(*quad, quad_info))
+      if (!quad->allow_overlay() || !GetTextureQuadInfo(*quad, quad_info))
         return false;
     } break;
     case DrawQuad::STREAM_VIDEO_CONTENT: {
       auto* quad = StreamVideoDrawQuad::MaterialCast(&draw_quad);
-      if (!GetVideoQuadInfo(*quad, quad_info))
+      if (!quad->allow_overlay() || !GetVideoQuadInfo(*quad, quad_info))
         return false;
     } break;
     case DrawQuad::IO_SURFACE_CONTENT: {
       auto* quad = IOSurfaceDrawQuad::MaterialCast(&draw_quad);
-      if (!GetIOSurfaceQuadInfo(*quad, quad_info))
+      if (!quad->allow_overlay || !GetIOSurfaceQuadInfo(*quad, quad_info))
         return false;
     } break;
     default:
       return false;
   }
 
   quad_info->format = RGBA_8888;
   quad_info->display_rect = OverlayCandidate::GetOverlayRect(
       draw_quad.shared_quad_state->quad_to_target_transform, draw_quad.rect);
   return true;
 }
 
 }  // namespace cc