Untie paths from entities (flutter#145)

Author: bdero

impeller/aiks/canvas.cc

@@ -8,7 +8,6 @@
 
 #include "flutter/fml/logging.h"
 #include "impeller/aiks/paint_pass_delegate.h"
-#include "impeller/entity/contents/clear_contents.h"
 #include "impeller/entity/contents/clip_contents.h"
 #include "impeller/entity/contents/text_contents.h"
 #include "impeller/entity/contents/texture_contents.h"
@@ -111,10 +110,9 @@ void Canvas::RestoreToCount(size_t count) {
 void Canvas::DrawPath(Path path, Paint paint) {
   Entity entity;
   entity.SetTransformation(GetCurrentTransformation());
-  entity.SetPath(std::move(path));
   entity.SetStencilDepth(GetStencilDepth());
   entity.SetBlendMode(paint.blend_mode);
-  entity.SetContents(paint.WithFilters(paint.CreateContentsForEntity()));
+  entity.SetContents(paint.WithFilters(paint.CreateContentsForEntity(std::move(path))));
 
   GetCurrentPass().AddEntity(std::move(entity));
 }
@@ -124,8 +122,7 @@ void Canvas::DrawPaint(Paint paint) {
   entity.SetTransformation(GetCurrentTransformation());
   entity.SetStencilDepth(GetStencilDepth());
   entity.SetBlendMode(paint.blend_mode);
-  entity.SetContents(
-      std::make_shared<ClearContents>(paint.CreateContentsForEntity()));
+  entity.SetContents(paint.CreateContentsForEntity({}, true));
 
   GetCurrentPass().AddEntity(std::move(entity));
 }
@@ -158,11 +155,11 @@ void Canvas::SaveLayer(Paint paint, std::optional<Rect> bounds) {
 
 void Canvas::ClipPath(Path path, Entity::ClipOperation clip_op) {
   auto contents = std::make_shared<ClipContents>();
+  contents->SetPath(std::move(path));
   contents->SetClipOperation(clip_op);
 
   Entity entity;
   entity.SetTransformation(GetCurrentTransformation());
-  entity.SetPath(std::move(path));
   entity.SetContents(std::move(contents));
   entity.SetStencilDepth(GetStencilDepth());
   entity.SetAddsToCoverage(false);
@@ -178,7 +175,6 @@ void Canvas::RestoreClip() {
   entity.SetTransformation(GetCurrentTransformation());
   // This path is empty because ClipRestoreContents just generates a quad that
   // takes up the full render target.
-  entity.SetPath({});
   entity.SetContents(std::make_shared<ClipRestoreContents>());
   entity.SetStencilDepth(GetStencilDepth());
   entity.SetAddsToCoverage(false);
@@ -234,12 +230,12 @@ void Canvas::DrawImageRect(std::shared_ptr<Image> image,
   }
 
   auto contents = std::make_shared<TextureContents>();
+  contents->SetPath(PathBuilder{}.AddRect(dest).TakePath());
   contents->SetTexture(image->GetTexture());
   contents->SetSourceRect(source);
   contents->SetSamplerDescriptor(std::move(sampler));
 
   Entity entity;
-  entity.SetPath(PathBuilder{}.AddRect(dest).TakePath());
   entity.SetBlendMode(paint.blend_mode);
   entity.SetStencilDepth(GetStencilDepth());
   entity.SetContents(paint.WithFilters(contents, false));
@@ -293,7 +289,6 @@ void Canvas::DrawTextFrame(TextFrame text_frame, Point position, Paint paint) {
   Entity entity;
   entity.SetTransformation(GetCurrentTransformation() *
                            Matrix::MakeTranslation(position));
-  entity.SetPath({});
   entity.SetStencilDepth(GetStencilDepth());
   entity.SetBlendMode(paint.blend_mode);
   entity.SetContents(paint.WithFilters(std::move(text_contents), true));

impeller/aiks/paint.cc

@@ -8,19 +8,23 @@
 
 namespace impeller {
 
-std::shared_ptr<Contents> Paint::CreateContentsForEntity() const {
+std::shared_ptr<Contents> Paint::CreateContentsForEntity(Path path,
+                                                         bool cover) const {
   if (contents) {
     return contents;
   }
 
   switch (style) {
     case Style::kFill: {
       auto solid_color = std::make_shared<SolidColorContents>();
+      solid_color->SetPath(std::move(path));
       solid_color->SetColor(color);
+      solid_color->SetCover(cover);
       return solid_color;
     }
     case Style::kStroke: {
       auto solid_stroke = std::make_shared<SolidStrokeContents>();
+      solid_stroke->SetPath(std::move(path));
       solid_stroke->SetColor(color);
       solid_stroke->SetStrokeSize(stroke_width);
       solid_stroke->SetStrokeMiter(stroke_miter);

impeller/aiks/paint.h

@@ -36,8 +36,6 @@ struct Paint {
   std::optional<MaskBlur> mask_blur;
   std::shared_ptr<Contents> contents;
 
-  std::shared_ptr<Contents> CreateContentsForEntity() const;
-
   /// @brief      Wrap this paint's configured filters to the given contents.
   /// @param[in]  input           The contents to wrap with paint's filters.
   /// @param[in]  is_solid_color  Affects mask blurring behavior. If false, use
@@ -52,6 +50,9 @@ struct Paint {
   std::shared_ptr<Contents> WithFilters(
       std::shared_ptr<Contents> input,
       std::optional<bool> is_solid_color = std::nullopt) const;
+
+  std::shared_ptr<Contents> CreateContentsForEntity(Path path = {},
+                                                    bool cover = false) const;
 };
 
 }  // namespace impeller

impeller/aiks/paint_pass_delegate.cc

@@ -6,6 +6,7 @@
 
 #include "impeller/entity/contents/contents.h"
 #include "impeller/entity/contents/texture_contents.h"
+#include "impeller/geometry/path_builder.h"
 
 namespace impeller {
 
@@ -34,6 +35,9 @@ bool PaintPassDelegate::CanCollapseIntoParentPass() {
 std::shared_ptr<Contents> PaintPassDelegate::CreateContentsForSubpassTarget(
     std::shared_ptr<Texture> target) {
   auto contents = std::make_shared<TextureContents>();
+  contents->SetPath(PathBuilder{}
+                        .AddRect(Rect::MakeSize(Size(target->GetSize())))
+                        .TakePath());
   contents->SetTexture(target);
   contents->SetSourceRect(Rect::MakeSize(Size(target->GetSize())));
   contents->SetOpacity(paint_.color.alpha);

impeller/entity/BUILD.gn

@@ -31,8 +31,6 @@ impeller_shaders("entity_shaders") {
 
 impeller_component("entity") {
   sources = [
-    "contents/clear_contents.cc",
-    "contents/clear_contents.h",
     "contents/clip_contents.cc",
     "contents/clip_contents.h",
     "contents/content_context.cc",

impeller/entity/contents/clear_contents.cc

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include <optional>
 #include "impeller/geometry/path_builder.h"
 #include "impeller/renderer/formats.h"
 #include "impeller/renderer/vertex_buffer_builder.h"
@@ -23,10 +24,18 @@ ClipContents::ClipContents() = default;
 
 ClipContents::~ClipContents() = default;
 
+void ClipContents::SetPath(Path path) {
+  path_ = std::move(path);
+}
+
 void ClipContents::SetClipOperation(Entity::ClipOperation clip_op) {
   clip_op_ = clip_op;
 }
 
+std::optional<Rect> ClipContents::GetCoverage(const Entity& entity) const {
+  return path_.GetTransformedBoundingBox(entity.GetTransformation());
+};
+
 bool ClipContents::Render(const ContentContext& renderer,
                           const Entity& entity,
                           RenderPass& pass) const {
@@ -77,7 +86,7 @@ bool ClipContents::Render(const ContentContext& renderer,
 
   cmd.pipeline = renderer.GetClipPipeline(options);
   cmd.BindVertices(SolidColorContents::CreateSolidFillVertices(
-      entity.GetPath(), pass.GetTransientsBuffer()));
+      path_, pass.GetTransientsBuffer()));
 
   info.mvp = Matrix::MakeOrthographic(pass.GetRenderTargetSize()) *
              entity.GetTransformation();
@@ -95,6 +104,11 @@ ClipRestoreContents::ClipRestoreContents() = default;
 
 ClipRestoreContents::~ClipRestoreContents() = default;
 
+std::optional<Rect> ClipRestoreContents::GetCoverage(
+    const Entity& entity) const {
+  return std::nullopt;
+};
+
 bool ClipRestoreContents::Render(const ContentContext& renderer,
                                  const Entity& entity,
                                  RenderPass& pass) const {

impeller/entity/contents/clear_contents.h

@@ -20,14 +20,20 @@ class ClipContents final : public Contents {
 
   ~ClipContents();
 
+  void SetPath(Path path);
+
   void SetClipOperation(Entity::ClipOperation clip_op);
 
+  // |Contents|
+  std::optional<Rect> GetCoverage(const Entity& entity) const override;
+
   // |Contents|
   bool Render(const ContentContext& renderer,
               const Entity& entity,
               RenderPass& pass) const override;
 
  private:
+  Path path_;
   Entity::ClipOperation clip_op_ = Entity::ClipOperation::kIntersect;
 
   FML_DISALLOW_COPY_AND_ASSIGN(ClipContents);
@@ -39,6 +45,9 @@ class ClipRestoreContents final : public Contents {
 
   ~ClipRestoreContents();
 
+  // |Contents|
+  std::optional<Rect> GetCoverage(const Entity& entity) const override;
+
   // |Contents|
   bool Render(const ContentContext& renderer,
               const Entity& entity,

impeller/entity/contents/clip_contents.cc

@@ -29,10 +29,6 @@ Contents::Contents() = default;
 
 Contents::~Contents() = default;
 
-std::optional<Rect> Contents::GetCoverage(const Entity& entity) const {
-  return entity.GetPathCoverage();
-}
-
 std::optional<Snapshot> Contents::RenderToSnapshot(
     const ContentContext& renderer,
     const Entity& entity) const {
@@ -46,7 +42,6 @@ std::optional<Snapshot> Contents::RenderToSnapshot(
       [&contents = *this, &entity, &bounds](const ContentContext& renderer,
                                             RenderPass& pass) -> bool {
         Entity sub_entity;
-        sub_entity.SetPath(entity.GetPath());
         sub_entity.SetBlendMode(Entity::BlendMode::kSourceOver);
         sub_entity.SetTransformation(
             Matrix::MakeTranslation(Vector3(-bounds->origin)) *

impeller/entity/contents/clip_contents.h

@@ -37,7 +37,7 @@ class Contents {
                       RenderPass& pass) const = 0;
 
   /// @brief Get the screen space bounding rectangle that this contents affects.
-  virtual std::optional<Rect> GetCoverage(const Entity& entity) const;
+  virtual std::optional<Rect> GetCoverage(const Entity& entity) const = 0;
 
   /// @brief Render this contents to a snapshot, respecting the entity's
   ///        transform, path, stencil depth, and blend mode.

impeller/entity/contents/contents.cc

@@ -129,11 +129,12 @@ bool FilterContents::Render(const ContentContext& renderer,
   // Draw the result texture, respecting the transform and clip stack.
 
   auto contents = std::make_shared<TextureContents>();
+  contents->SetPath(
+      PathBuilder{}.AddRect(filter_coverage.value()).GetCurrentPath());
   contents->SetTexture(snapshot.texture);
   contents->SetSourceRect(Rect::MakeSize(Size(snapshot.texture->GetSize())));
 
   Entity e;
-  e.SetPath(PathBuilder{}.AddRect(filter_coverage.value()).GetCurrentPath());
   e.SetBlendMode(entity.GetBlendMode());
   e.SetStencilDepth(entity.GetStencilDepth());
   return contents->Render(renderer, e, pass);

impeller/entity/contents/contents.h

@@ -146,23 +146,13 @@ std::optional<Snapshot> TextureFilterInput::GetSnapshot(
 
 std::optional<Rect> TextureFilterInput::GetCoverage(
     const Entity& entity) const {
-  auto path_bounds = entity.GetPath().GetBoundingBox();
-  if (!path_bounds.has_value()) {
-    return std::nullopt;
-  }
   return Rect::MakeSize(Size(texture_->GetSize()))
       .TransformBounds(GetTransform(entity));
 }
 
 Matrix TextureFilterInput::GetLocalTransform(const Entity& entity) const {
-  // Compute the local transform such that the texture will cover the entity
-  // path bounding box.
-  auto path_bounds = entity.GetPath().GetBoundingBox();
-  if (!path_bounds.has_value()) {
-    return Matrix();
-  }
-  return Matrix::MakeTranslation(path_bounds->origin) *
-         Matrix::MakeScale(Vector2(path_bounds->size) / texture_->GetSize());
+  // Compute the local transform such that the texture is centered.
+  return Matrix::MakeTranslation(-Point(texture_->GetSize()) / 2);
 }
 
 }  // namespace impeller