Optimize render passes with single quads

cc/output/gl_renderer.cc

Index: cc/output/gl_renderer.cc
diff --git a/cc/output/gl_renderer.cc b/cc/output/gl_renderer.cc
index 7cf5a00face44d5bfa4fdf49f6e805ae4d5b209c..0800eb6051a62dacb1afeb23c60a436e38560112 100644
--- a/cc/output/gl_renderer.cc
+++ b/cc/output/gl_renderer.cc
@@ -589,7 +589,8 @@ void GLRenderer::DrawDebugBorderQuad(const DrawingFrame* frame,
 
 static sk_sp<SkImage> WrapTexture(
     const ResourceProvider::ScopedReadLockGL& lock,
-    GrContext* context) {
+    GrContext* context,
+    bool is_render_pass_input) {
   // Wrap a given texture in a Ganesh platform texture.
   GrBackendTextureDesc backend_texture_description;
   GrGLTextureInfo texture_info;
@@ -600,7 +601,9 @@ static sk_sp<SkImage> WrapTexture(
   backend_texture_description.fConfig = kSkia8888_GrPixelConfig;
   backend_texture_description.fTextureHandle =
       skia::GrGLTextureInfoToGrBackendObject(texture_info);
-  backend_texture_description.fOrigin = kBottomLeft_GrSurfaceOrigin;
+  backend_texture_description.fOrigin = is_render_pass_input
+                                            ? kBottomLeft_GrSurfaceOrigin
+                                            : kTopLeft_GrSurfaceOrigin;
 
   return SkImage::MakeFromTexture(context, backend_texture_description);
 }
@@ -612,16 +615,19 @@ static sk_sp<SkImage> ApplyImageFilter(
     const gfx::RectF& dst_rect,
     const gfx::Vector2dF& scale,
     sk_sp<SkImageFilter> filter,
-    ScopedResource* source_texture_resource,
+    const Resource* source_texture_resource,
     SkIPoint* offset,
-    SkIRect* subset) {
+    SkIRect* subset,
+    bool is_render_pass_input) {
   if (!filter || !use_gr_context)
     return nullptr;
 
   ResourceProvider::ScopedReadLockGL lock(resource_provider,
                                           source_texture_resource->id());
 
-  sk_sp<SkImage> src_image = WrapTexture(lock, use_gr_context->context());
+  sk_sp<SkImage> src_image =
+      WrapTexture(lock, use_gr_context->context(), is_render_pass_input);
+
   if (!src_image) {
     TRACE_EVENT_INSTANT0("cc",
                          "ApplyImageFilter wrap background texture failed",
@@ -852,7 +858,9 @@ sk_sp<SkImage> GLRenderer::ApplyBackgroundFilters(
   ResourceProvider::ScopedReadLockGL lock(resource_provider_,
                                           background_texture->id());
 
-  sk_sp<SkImage> src_image = WrapTexture(lock, use_gr_context->context());
+  bool is_render_pass_input = true;
+  sk_sp<SkImage> src_image =
+      WrapTexture(lock, use_gr_context->context(), is_render_pass_input);
   if (!src_image) {
     TRACE_EVENT_INSTANT0(
         "cc", "ApplyBackgroundFilters wrap background texture failed",
@@ -910,14 +918,72 @@ gfx::QuadF MapQuadToLocalSpace(const gfx::Transform& device_transform,
   return local_quad;
 }
 
+const TileDrawQuad* GLRenderer::CanPassBeDrawnDirectly(const RenderPass* pass) {
+  // Can only collapse a single tile quad.
+  if (pass->quad_list.size() != 1)
+    return nullptr;
+  // If we need copy requests, then render pass has to exist.
+  if (!pass->copy_requests.empty())
+    return nullptr;
+
+  const DrawQuad* quad = *pass->quad_list.BackToFrontBegin();
+  // Hack: this could be supported by concatenating transforms, but
+  // in practice if there is one quad, it is at the origin of the render pass.
+  if (!quad->shared_quad_state->quad_to_target_transform.IsIdentity())
+    return nullptr;
+  // The quad is expected to be the entire layer so that AA edges are correct.
+  if (gfx::Rect(quad->shared_quad_state->quad_layer_bounds) != quad->rect)
+    return nullptr;
+  if (quad->material != DrawQuad::TILED_CONTENT)
+    return nullptr;
+
+  const TileDrawQuad* tile_quad = TileDrawQuad::MaterialCast(quad);
+  // Hack: this could be supported by passing in a subrectangle to draw
+  // render pass, although in practice if there is only one quad there
+  // will be no border texels on the input.
+  if (tile_quad->tex_coord_rect != gfx::RectF(tile_quad->rect))
+    return nullptr;
+  // Tile quad features not supported in render pass shaders.
+  if (tile_quad->swizzle_contents || tile_quad->nearest_neighbor)
+    return nullptr;
+  // BUG=skia:3868, Skia currently doesn't support texture rectangle inputs.
+  // See also the DCHECKs about GL_TEXTURE_2D in DrawRenderPassQuad.
+  GLenum target =
+      resource_provider_->GetResourceTextureTarget(tile_quad->resource_id());
+  if (target != GL_TEXTURE_2D)
+    return nullptr;
+
+  return tile_quad;
+}
+
 void GLRenderer::DrawRenderPassQuad(DrawingFrame* frame,
                                     const RenderPassDrawQuad* quad,
                                     const gfx::QuadF* clip_region) {
-  ScopedResource* contents_texture =
-      render_pass_textures_[quad->render_pass_id].get();
-  DCHECK(contents_texture);
-  DCHECK(contents_texture->id());
+  auto bypass = render_pass_bypass_quads_.find(quad->render_pass_id);
+  if (bypass != render_pass_bypass_quads_.end()) {
+    TileDrawQuad* tile_quad = &bypass->second;
+    // TODO(enne): format here doesn't appear to get used.
+    Resource tile_resource(tile_quad->resource_id(), tile_quad->texture_size,
+                           ResourceFormat::RGBA_8888);
+    bool is_render_pass_input = false;
+    DrawRenderPassQuadInternal(frame, quad, clip_region, &tile_resource,
+                               is_render_pass_input);
+  } else {
+    ScopedResource* contents_texture =
+        render_pass_textures_[quad->render_pass_id].get();
+    DCHECK(contents_texture);
+    DCHECK(contents_texture->id());
+    bool is_render_pass_input = true;
+    DrawRenderPassQuadInternal(frame, quad, clip_region, contents_texture,
+                               is_render_pass_input);
+  }
+}
 
+void GLRenderer::DrawRenderPassQuadInternal(DrawingFrame* frame,
+                                            const RenderPassDrawQuad* quad,
+                                            const gfx::QuadF* clip_region,
+                                            const Resource* contents_texture,
+                                            bool is_render_pass_input) {
   SkMatrix scale_matrix;
   scale_matrix.setScale(quad->filters_scale.x(), quad->filters_scale.y());
   gfx::RectF dst_rect(quad->filters.MapRect(quad->rect, scale_matrix));
@@ -1022,7 +1088,6 @@ void GLRenderer::DrawRenderPassQuad(DrawingFrame* frame,
   SkScalar color_matrix[20];
   bool use_color_matrix = false;
   gfx::Size texture_size = contents_texture->size();
-  bool flip_texture = true;
   gfx::Point src_offset;
   if (!quad->filters.IsEmpty()) {
     sk_sp<SkImageFilter> filter = RenderSurfaceFilters::BuildImageFilter(
@@ -1057,13 +1122,12 @@ void GLRenderer::DrawRenderPassQuad(DrawingFrame* frame,
         SkIPoint offset;
         SkIRect subset;
         gfx::RectF src_rect(quad->rect);
-        filter_image = ApplyImageFilter(ScopedUseGrContext::Create(this, frame),
-                                        resource_provider_, src_rect, dst_rect,
-                                        quad->filters_scale, std::move(filter),
-                                        contents_texture, &offset, &subset);
-        if (!filter_image) {
+        filter_image = ApplyImageFilter(
+            ScopedUseGrContext::Create(this, frame), resource_provider_,
+            src_rect, dst_rect, quad->filters_scale, std::move(filter),
+            contents_texture, &offset, &subset, is_render_pass_input);
+        if (!filter_image)
           return;
-        }
         filter_image_id = skia::GrBackendObjectToGrGLTextureInfo(
                               filter_image->getTextureHandle(true))
                               ->fID;
@@ -1074,7 +1138,8 @@ void GLRenderer::DrawRenderPassQuad(DrawingFrame* frame,
             gfx::RectF(src_rect.x() + offset.fX, src_rect.y() + offset.fY,
                        subset.width(), subset.height());
         src_offset.SetPoint(subset.x(), subset.y());
-        flip_texture =
+        // If the output of the filter needs to be flipped.
+        is_render_pass_input =

[Stephen White, 2016/06/03 19:30:15]

<bikeshed> At this point, it's not really true that it's a render pass input
anymore. Could we keep this named "flip_texture"? </bikeshed>

[enne (OOO), 2016/06/03 20:40:22]

Haha, yeah sure.  I had named it differently before your patch.  I think
flip_texture is confusing to me, because we already have a flip later in the
pipeline, so this is really unflipped but needs to be double flipped, so I was
trying to name it something better.

I can change it back to flip_texture.  :)

             filter_image->getTexture()->origin() == kBottomLeft_GrSurfaceOrigin;
       }
     }
@@ -1192,13 +1257,15 @@ void GLRenderer::DrawRenderPassQuad(DrawingFrame* frame,
   tex_rect.Scale(1.0f / texture_size.width(), 1.0f / texture_size.height());
 
   DCHECK(locations.tex_transform != -1 || IsContextLost());
-  if (flip_texture) {
+  if (is_render_pass_input) {
     // Flip the content vertically in the shader, as the RenderPass input
     // texture is already oriented the same way as the framebuffer, but the
     // projection transform does a flip.
     gl_->Uniform4f(locations.tex_transform, tex_rect.x(), 1.0f - tex_rect.y(),
                    tex_rect.width(), -tex_rect.height());
   } else {
+    // Tile textures are oriented opposite the framebuffer, so can use
+    // the projection transform to do the flip.
     gl_->Uniform4f(locations.tex_transform, tex_rect.x(), tex_rect.y(),
                    tex_rect.width(), tex_rect.height());
   }
@@ -1214,16 +1281,24 @@ void GLRenderer::DrawRenderPassQuad(DrawingFrame* frame,
       mask_uv_rect.Scale(quad->mask_texture_size.width(),
                          quad->mask_texture_size.height());
     }
-
-    // Mask textures are oriented vertically flipped relative to the framebuffer
-    // and the RenderPass contents texture, so we flip the tex coords from the
-    // RenderPass texture to find the mask texture coords.
-    gl_->Uniform2f(
-        locations.mask_tex_coord_offset, mask_uv_rect.x(),
-        mask_uv_rect.height() / tex_rect.height() + mask_uv_rect.y());
-    gl_->Uniform2f(locations.mask_tex_coord_scale,
-                   mask_uv_rect.width() / tex_rect.width(),
-                   -mask_uv_rect.height() / tex_rect.height());
+    if (is_render_pass_input) {
+      // Mask textures are oriented vertically flipped relative to the
+      // framebuffer and the RenderPass contents texture, so we flip the tex
+      // coords from the RenderPass texture to find the mask texture coords.
+      gl_->Uniform2f(
+          locations.mask_tex_coord_offset, mask_uv_rect.x(),
+          mask_uv_rect.height() / tex_rect.height() + mask_uv_rect.y());
+      gl_->Uniform2f(locations.mask_tex_coord_scale,
+                     mask_uv_rect.width() / tex_rect.width(),
+                     -mask_uv_rect.height() / tex_rect.height());
+    } else {
+      // Tile textures are oriented the same way as mask textures.
+      gl_->Uniform2f(locations.mask_tex_coord_offset, mask_uv_rect.x(),
+                     mask_uv_rect.y());
+      gl_->Uniform2f(locations.mask_tex_coord_scale,
+                     mask_uv_rect.width() / tex_rect.width(),
+                     mask_uv_rect.height() / tex_rect.height());
+    }
 
     last_texture_unit = 1;
   }