cc: Change the restrictions on overlays for video

cc/output/overlay_strategy_single_on_top.cc

 // Copyright 2014 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_single_on_top.h"
 
+#include <limits>
+
 #include "cc/quads/draw_quad.h"
+#include "cc/quads/solid_color_draw_quad.h"
+#include "cc/quads/stream_video_draw_quad.h"
 #include "cc/quads/texture_draw_quad.h"
+#include "ui/gfx/geometry/point3_f.h"
 #include "ui/gfx/geometry/rect_conversions.h"
 #include "ui/gfx/transform.h"
 
 namespace cc {
 
 OverlayStrategySingleOnTop::OverlayStrategySingleOnTop(
     OverlayCandidateValidator* capability_checker,
     ResourceProvider* resource_provider)
     : capability_checker_(capability_checker),
       resource_provider_(resource_provider) {}
 
+bool OverlayStrategySingleOnTop::IsOverlayQuad(const DrawQuad* draw_quad) {
+  unsigned int resource_id;
+  if (draw_quad->material == DrawQuad::TEXTURE_CONTENT) {

[danakj, 2015/01/21 23:30:33]

how about a switch instead of an if/elseif/else? then if a new quad type happens
we'll have to come visit here and see if it makes sense to handle it.

[achaulk, 2015/01/23 20:10:55]

Done.

+    const TextureDrawQuad* quad = TextureDrawQuad::MaterialCast(draw_quad);
+    if (!quad) {

[danakj, 2015/01/21 23:30:33]

The material cast will DCHECK if it's not a texture quad. You don't need to
handle null here

+      return false;
+    }
+    resource_id = quad->resource_id;
+  } else if (draw_quad->material == DrawQuad::STREAM_VIDEO_CONTENT) {
+    const StreamVideoDrawQuad* quad =
+        StreamVideoDrawQuad::MaterialCast(draw_quad);
+    if (!quad) {

[danakj, 2015/01/21 23:30:33]

ditto

+      return false;
+    }
+    resource_id = quad->resource_id;
+  } else {
+    return false;
+  }
+  return resource_provider_->AllowOverlay(resource_id);
+}
+
+bool OverlayStrategySingleOnTop::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;
+
+  if (draw_quad.material == DrawQuad::TEXTURE_CONTENT) {
+    const TextureDrawQuad& quad = *TextureDrawQuad::MaterialCast(&draw_quad);
+    gfx::OverlayTransform overlay_transform =
+        OverlayCandidate::GetOverlayTransform(quad.quadTransform(),
+                                              quad.flipped);
+    if (quad.background_color != SK_ColorTRANSPARENT ||
+        quad.premultiplied_alpha ||
+        overlay_transform == gfx::OVERLAY_TRANSFORM_INVALID)
+      return false;
+    quad_info->resource_id = quad.resource_id;
+    quad_info->transform = overlay_transform;
+    quad_info->uv_rect = BoundingRect(quad.uv_top_left, quad.uv_bottom_right);
+  } else if (draw_quad.material == DrawQuad::STREAM_VIDEO_CONTENT) {
+    const StreamVideoDrawQuad& quad =
+        *StreamVideoDrawQuad::MaterialCast(&draw_quad);
+    gfx::OverlayTransform overlay_transform =
+        OverlayCandidate::GetOverlayTransform(quad.quadTransform(), false);

[danakj, 2015/01/21 23:30:33]

use a temp var to give boolean literal a name

[achaulk, 2015/01/23 20:10:55]

Done.

+    if (overlay_transform == gfx::OVERLAY_TRANSFORM_INVALID)
+      return false;
+    if (!quad.matrix.IsScaleOrTranslation()) {
+      // We cannot handle anything other than scaling & translation for texture
+      // coordinates yet.
+      return false;
+    }
+    quad_info->resource_id = quad.resource_id;
+    quad_info->transform = overlay_transform;
+
+    gfx::Point3F uv0 = gfx::Point3F(0, 0, 0);
+    gfx::Point3F uv1 = gfx::Point3F(1, 1, 0);
+    quad.matrix.TransformPoint(&uv0);
+    quad.matrix.TransformPoint(&uv1);
+    gfx::Vector3dF delta = uv1 - uv0;
+    if (delta.x() < 0) {
+      if (quad_info->transform == gfx::OVERLAY_TRANSFORM_NONE) {
+        quad_info->transform = gfx::OVERLAY_TRANSFORM_FLIP_HORIZONTAL;

[danakj, 2015/01/21 23:30:33]

This all gets very nested, it'd be nice to do this in a way with less nesting.
One way that comes to mind is to break the TEXTURE and the STREAM cases out into
individual helper functions?

[achaulk, 2015/01/23 20:10:55]

Done.

+        float x0 = uv0.x();
+        uv0.set_x(uv1.x());
+        uv1.set_x(x0);
+        delta.set_x(-delta.x());
+      } else {
+        return false;
+      }
+    }
+    if (delta.y() < 0) {
+      // In this situation, uv0y < uv1y. Since we overlay inverted, a request
+      // to invert the source texture means we can just output the texture
+      // normally and it will be correct.
+      quad_info->uv_rect = gfx::RectF(uv0.x(), uv1.y(), delta.x(), -delta.y());
+    } else {
+      if (quad_info->transform == gfx::OVERLAY_TRANSFORM_NONE) {
+        quad_info->transform = gfx::OVERLAY_TRANSFORM_FLIP_VERTICAL;
+      } else {
+        return false;
+      }
+      quad_info->uv_rect = gfx::RectF(uv0.x(), uv0.y(), delta.x(), delta.y());
+    }
+  } else {
+    return false;
+  }
+
+  quad_info->format = RGBA_8888;
+  quad_info->display_rect = OverlayCandidate::GetOverlayRect(
+      draw_quad.quadTransform(), draw_quad.rect);
+  return true;
+}
+
+bool OverlayStrategySingleOnTop::QuadBlocksOverlay(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->opacity();
+    float alpha = (SkColorGetA(color) * (1.0f / 255.0f)) * opacity;
+    // Ignore transparent solid color quads.
+    return !solid_quad->ShouldDrawWithBlending() ||
+           alpha >= std::numeric_limits<float>::epsilon();
+  }
+  return true;
+}
+
 bool OverlayStrategySingleOnTop::Attempt(
     RenderPassList* render_passes_in_draw_order,
     OverlayCandidateList* candidate_list) {
   // Only attempt to handle very simple case for now.
   if (!capability_checker_)
     return false;
 
   RenderPass* root_render_pass = render_passes_in_draw_order->back();
   DCHECK(root_render_pass);
 
+  OverlayCandidate candidate;
   QuadList& quad_list = root_render_pass->quad_list;
   auto candidate_iterator = quad_list.end();
   for (auto it = quad_list.begin(); it != quad_list.end(); ++it) {
     const DrawQuad* draw_quad = *it;
-    if (draw_quad->material == DrawQuad::TEXTURE_CONTENT) {
-      const TextureDrawQuad& quad = *TextureDrawQuad::MaterialCast(draw_quad);
-      if (!resource_provider_->AllowOverlay(quad.resource_id)) {
-        continue;
-      }
+    if (IsOverlayQuad(draw_quad)) {
       // Check that no prior quads overlap it.
       bool intersects = false;
       gfx::RectF rect = draw_quad->rect;
       draw_quad->quadTransform().TransformRect(&rect);
       for (auto overlap_iter = quad_list.cbegin(); overlap_iter != it;
            ++overlap_iter) {
         gfx::RectF overlap_rect = overlap_iter->rect;
         overlap_iter->quadTransform().TransformRect(&overlap_rect);
-        if (rect.Intersects(overlap_rect)) {
+        if (rect.Intersects(overlap_rect) && QuadBlocksOverlay(*overlap_iter)) {

[danakj, 2015/01/21 23:30:33]

This seems like a 3rd change, allowing overlapping non-opaque solid color quads
above an overlay? Can you split this out into its own CL?

[achaulk, 2015/01/23 20:10:55]

Done.

           intersects = true;
           break;
         }
       }
-      if (intersects)
+      if (intersects || !GetCandidateQuadInfo(*draw_quad, &candidate))
         continue;
       candidate_iterator = it;
       break;
     }
   }
   if (candidate_iterator == quad_list.end())
     return false;
-  const TextureDrawQuad& quad =
-      *TextureDrawQuad::MaterialCast(*candidate_iterator);
-
-  // Simple quads only.
-  gfx::OverlayTransform overlay_transform =
-      OverlayCandidate::GetOverlayTransform(quad.quadTransform(), quad.flipped);
-  if (overlay_transform == gfx::OVERLAY_TRANSFORM_INVALID ||
-      !quad.quadTransform().IsIdentityOrTranslation() || quad.needs_blending ||
-      quad.shared_quad_state->opacity != 1.f ||
-      quad.shared_quad_state->blend_mode != SkXfermode::kSrcOver_Mode ||
-      quad.premultiplied_alpha || quad.background_color != SK_ColorTRANSPARENT)
-    return false;
 
   // Add our primary surface.
   OverlayCandidateList candidates;
   OverlayCandidate main_image;
   main_image.display_rect = root_render_pass->output_rect;
   main_image.format = RGBA_8888;
+  main_image.plane_z_order = 0;

[danakj, 2015/01/21 23:30:33]

Unrelated change?

[achaulk, 2015/01/23 20:10:55]

Just making it explicit, the ctor does this too

   candidates.push_back(main_image);
 
   // Add the overlay.
-  OverlayCandidate candidate;
-  candidate.transform = overlay_transform;
-  candidate.display_rect =
-      OverlayCandidate::GetOverlayRect(quad.quadTransform(), quad.rect);
-  candidate.uv_rect = BoundingRect(quad.uv_top_left, quad.uv_bottom_right);
-  candidate.format = RGBA_8888;
-  candidate.resource_id = quad.resource_id;
   candidate.plane_z_order = 1;
   candidates.push_back(candidate);
 
   // Check for support.
   capability_checker_->CheckOverlaySupport(&candidates);
 
   // If the candidate can be handled by an overlay, create a pass for it.
   if (candidates[1].overlay_handled) {
     quad_list.EraseAndInvalidateAllPointers(candidate_iterator);
     candidate_list->swap(candidates);
     return true;
   }
   return false;
 }
 
 }  // namespace cc