Rework the confusingly named renderer subsystem instances.

engine/src/flutter/impeller/BUILD.gn

@@ -3,7 +3,10 @@
 # found in the LICENSE file.
 
 config("impeller_public_config") {
-  include_dirs = [ ".." ]
+  include_dirs = [
+    "..",
+    ".",
+  ]
 }
 
 is_host = is_mac || is_linux || is_win

engine/src/flutter/impeller/aiks/BUILD.gn

@@ -6,8 +6,8 @@ import("../tools/impeller.gni")
 
 impeller_component("aiks") {
   sources = [
-    "aiks_renderer.cc",
-    "aiks_renderer.h",
+    "aiks_context.cc",
+    "aiks_context.h",
     "canvas.cc",
     "canvas.h",
     "image.cc",

engine/src/flutter/impeller/aiks/aiks_context.cc

@@ -2,39 +2,39 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "impeller/aiks/aiks_renderer.h"
+#include "impeller/aiks/aiks_context.h"
 
 #include "impeller/aiks/picture.h"
 
 namespace impeller {
 
-AiksRenderer::AiksRenderer(std::shared_ptr<Context> context)
+AiksContext::AiksContext(std::shared_ptr<Context> context)
     : context_(std::move(context)) {
   if (!context_ || !context_->IsValid()) {
     return;
   }
 
-  content_renderer_ = std::make_unique<ContentRenderer>(context_);
-  if (!content_renderer_->IsValid()) {
+  content_context_ = std::make_unique<ContentContext>(context_);
+  if (!content_context_->IsValid()) {
     return;
   }
 
   is_valid_ = true;
 }
 
-AiksRenderer::~AiksRenderer() = default;
+AiksContext::~AiksContext() = default;
 
-bool AiksRenderer::IsValid() const {
+bool AiksContext::IsValid() const {
   return is_valid_;
 }
 
-bool AiksRenderer::Render(const Picture& picture, RenderPass& parent_pass) {
+bool AiksContext::Render(const Picture& picture, RenderPass& parent_pass) {
   if (!IsValid()) {
     return false;
   }
 
   if (picture.pass) {
-    return picture.pass->Render(*content_renderer_, parent_pass);
+    return picture.pass->Render(*content_context_, parent_pass);
   }
 
   return true;

engine/src/flutter/impeller/aiks/aiks_context.h

@@ -7,7 +7,7 @@
 #include <memory>
 
 #include "flutter/fml/macros.h"
-#include "impeller/entity/content_renderer.h"
+#include "impeller/entity/content_context.h"
 #include "impeller/renderer/context.h"
 
 namespace impeller {
@@ -15,11 +15,11 @@ namespace impeller {
 struct Picture;
 class RenderPass;
 
-class AiksRenderer {
+class AiksContext {
  public:
-  AiksRenderer(std::shared_ptr<Context> context);
+  AiksContext(std::shared_ptr<Context> context);
 
-  ~AiksRenderer();
+  ~AiksContext();
 
   bool IsValid() const;
 
@@ -27,10 +27,10 @@ class AiksRenderer {
 
  private:
   std::shared_ptr<Context> context_;
-  std::unique_ptr<ContentRenderer> content_renderer_;
+  std::unique_ptr<ContentContext> content_context_;
   bool is_valid_ = false;
 
-  FML_DISALLOW_COPY_AND_ASSIGN(AiksRenderer);
+  FML_DISALLOW_COPY_AND_ASSIGN(AiksContext);
 };
 
 }  // namespace impeller

engine/src/flutter/impeller/aiks/aiks_playground.cc

@@ -4,7 +4,7 @@
 
 #include "impeller/aiks/aiks_playground.h"
 
-#include "impeller/aiks/aiks_renderer.h"
+#include "impeller/aiks/aiks_context.h"
 
 namespace impeller {
 
@@ -13,7 +13,7 @@ AiksPlayground::AiksPlayground() = default;
 AiksPlayground::~AiksPlayground() = default;
 
 bool AiksPlayground::OpenPlaygroundHere(const Picture& picture) {
-  AiksRenderer renderer(GetContext());
+  AiksContext renderer(GetContext());
 
   if (!renderer.IsValid()) {
     return false;

engine/src/flutter/impeller/display_list/display_list_dispatcher.h

@@ -5,6 +5,7 @@
 #pragma once
 
 #include "flutter/display_list/display_list.h"
+#include "flutter/display_list/display_list_dispatcher.h"
 #include "flutter/fml/macros.h"
 #include "impeller/aiks/canvas.h"
 #include "impeller/aiks/paint.h"

engine/src/flutter/impeller/entity/BUILD.gn

@@ -21,8 +21,8 @@ impeller_shaders("entity_shaders") {
 
 impeller_component("entity") {
   sources = [
-    "content_renderer.cc",
-    "content_renderer.h",
+    "content_context.cc",
+    "content_context.h",
     "contents.cc",
     "contents.h",
     "entity.cc",

engine/src/flutter/impeller/entity/content_context.cc

@@ -2,11 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "impeller/entity/content_renderer.h"
+#include "impeller/entity/content_context.h"
 
 namespace impeller {
 
-ContentRenderer::ContentRenderer(std::shared_ptr<Context> context)
+ContentContext::ContentContext(std::shared_ptr<Context> context)
     : context_(std::move(context)) {
   if (!context_ || !context_->IsValid()) {
     return;
@@ -46,13 +46,13 @@ ContentRenderer::ContentRenderer(std::shared_ptr<Context> context)
   is_valid_ = true;
 }
 
-ContentRenderer::~ContentRenderer() = default;
+ContentContext::~ContentContext() = default;
 
-bool ContentRenderer::IsValid() const {
+bool ContentContext::IsValid() const {
   return is_valid_;
 }
 
-std::shared_ptr<Context> ContentRenderer::GetContext() const {
+std::shared_ptr<Context> ContentContext::GetContext() const {
   return context_;
 }
 

engine/src/flutter/impeller/entity/content_context.h

@@ -33,7 +33,7 @@ using SolidStrokePipeline =
 // to redirect writing to the stencil instead of color attachments.
 using ClipPipeline = PipelineT<SolidFillVertexShader, SolidFillFragmentShader>;
 
-class ContentRenderer {
+class ContentContext {
  public:
   struct Options {
     SampleCount sample_count = SampleCount::kCount1;
@@ -51,9 +51,9 @@ class ContentRenderer {
     };
   };
 
-  ContentRenderer(std::shared_ptr<Context> context);
+  ContentContext(std::shared_ptr<Context> context);
 
-  ~ContentRenderer();
+  ~ContentContext();
 
   bool IsValid() const;
 
@@ -128,7 +128,7 @@ class ContentRenderer {
 
   bool is_valid_ = false;
 
-  FML_DISALLOW_COPY_AND_ASSIGN(ContentRenderer);
+  FML_DISALLOW_COPY_AND_ASSIGN(ContentContext);
 };
 
 }  // namespace impeller

engine/src/flutter/impeller/entity/contents.cc

@@ -7,7 +7,7 @@
 #include <memory>
 
 #include "flutter/fml/logging.h"
-#include "impeller/entity/content_renderer.h"
+#include "impeller/entity/content_context.h"
 #include "impeller/entity/entity.h"
 #include "impeller/geometry/path_builder.h"
 #include "impeller/geometry/vector.h"
@@ -19,8 +19,8 @@
 
 namespace impeller {
 
-static ContentRenderer::Options OptionsFromPass(const RenderPass& pass) {
-  ContentRenderer::Options opts;
+static ContentContext::Options OptionsFromPass(const RenderPass& pass) {
+  ContentContext::Options opts;
   opts.sample_count = pass.GetRenderTarget().GetSampleCount();
   return opts;
 }
@@ -60,7 +60,7 @@ const std::vector<Color>& LinearGradientContents::GetColors() const {
   return colors_;
 }
 
-bool LinearGradientContents::Render(const ContentRenderer& renderer,
+bool LinearGradientContents::Render(const ContentContext& renderer,
                                     const Entity& entity,
                                     RenderPass& pass) const {
   using VS = GradientFillPipeline::VertexShader;
@@ -137,7 +137,7 @@ static VertexBuffer CreateSolidFillVertices(const Path& path,
   return vtx_builder.CreateVertexBuffer(buffer);
 }
 
-bool SolidColorContents::Render(const ContentRenderer& renderer,
+bool SolidColorContents::Render(const ContentContext& renderer,
                                 const Entity& entity,
                                 RenderPass& pass) const {
   if (color_.IsTransparent()) {
@@ -194,7 +194,7 @@ void TextureContents::SetOpacity(Scalar opacity) {
   opacity_ = opacity;
 }
 
-bool TextureContents::Render(const ContentRenderer& renderer,
+bool TextureContents::Render(const ContentContext& renderer,
                              const Entity& entity,
                              RenderPass& pass) const {
   if (texture_ == nullptr) {
@@ -328,7 +328,7 @@ static VertexBuffer CreateSolidStrokeVertices(const Path& path,
   return vtx_builder.CreateVertexBuffer(buffer);
 }
 
-bool SolidStrokeContents::Render(const ContentRenderer& renderer,
+bool SolidStrokeContents::Render(const ContentContext& renderer,
                                  const Entity& entity,
                                  RenderPass& pass) const {
   if (color_.IsTransparent() || stroke_size_ <= 0.0) {
@@ -377,7 +377,7 @@ ClipContents::ClipContents() = default;
 
 ClipContents::~ClipContents() = default;
 
-bool ClipContents::Render(const ContentRenderer& renderer,
+bool ClipContents::Render(const ContentContext& renderer,
                           const Entity& entity,
                           RenderPass& pass) const {
   using VS = ClipPipeline::VertexShader;

engine/src/flutter/impeller/entity/contents.h

@@ -15,7 +15,7 @@
 
 namespace impeller {
 
-class ContentRenderer;
+class ContentContext;
 class Entity;
 class Surface;
 class RenderPass;
@@ -26,7 +26,7 @@ class Contents {
 
   virtual ~Contents();
 
-  virtual bool Render(const ContentRenderer& renderer,
+  virtual bool Render(const ContentContext& renderer,
                       const Entity& entity,
                       RenderPass& pass) const = 0;
 
@@ -41,7 +41,7 @@ class LinearGradientContents final : public Contents {
   ~LinearGradientContents() override;
 
   // |Contents|
-  bool Render(const ContentRenderer& renderer,
+  bool Render(const ContentContext& renderer,
               const Entity& entity,
               RenderPass& pass) const override;
 
@@ -72,7 +72,7 @@ class SolidColorContents final : public Contents {
   const Color& GetColor() const;
 
   // |Contents|
-  bool Render(const ContentRenderer& renderer,
+  bool Render(const ContentContext& renderer,
               const Entity& entity,
               RenderPass& pass) const override;
 
@@ -99,7 +99,7 @@ class TextureContents final : public Contents {
   const IRect& GetSourceRect() const;
 
   // |Contents|
-  bool Render(const ContentRenderer& renderer,
+  bool Render(const ContentContext& renderer,
               const Entity& entity,
               RenderPass& pass) const override;
 
@@ -126,7 +126,7 @@ class SolidStrokeContents final : public Contents {
   Scalar GetStrokeSize() const;
 
   // |Contents|
-  bool Render(const ContentRenderer& renderer,
+  bool Render(const ContentContext& renderer,
               const Entity& entity,
               RenderPass& pass) const override;
 
@@ -144,7 +144,7 @@ class ClipContents final : public Contents {
   ~ClipContents();
 
   // |Contents|
-  bool Render(const ContentRenderer& renderer,
+  bool Render(const ContentContext& renderer,
               const Entity& entity,
               RenderPass& pass) const override;
 

engine/src/flutter/impeller/entity/entity.cc

@@ -4,7 +4,7 @@
 
 #include "impeller/entity/entity.h"
 
-#include "impeller/entity/content_renderer.h"
+#include "impeller/entity/content_context.h"
 #include "impeller/renderer/render_pass.h"
 
 namespace impeller {
@@ -65,7 +65,7 @@ void Entity::IncrementStencilDepth(uint32_t increment) {
   stencil_depth_ += increment;
 }
 
-bool Entity::Render(ContentRenderer& renderer, RenderPass& parent_pass) const {
+bool Entity::Render(ContentContext& renderer, RenderPass& parent_pass) const {
   if (!contents_) {
     return true;
   }

engine/src/flutter/impeller/entity/entity.h

@@ -46,7 +46,7 @@ class Entity {
 
   uint32_t GetStencilDepth() const;
 
-  bool Render(ContentRenderer& renderer, RenderPass& parent_pass) const;
+  bool Render(ContentContext& renderer, RenderPass& parent_pass) const;
 
  private:
   Matrix transformation_;

engine/src/flutter/impeller/entity/entity_pass.cc

@@ -4,7 +4,7 @@
 
 #include "impeller/entity/entity_pass.h"
 
-#include "impeller/entity/content_renderer.h"
+#include "impeller/entity/content_context.h"
 #include "impeller/geometry/path_builder.h"
 #include "impeller/renderer/command_buffer.h"
 #include "impeller/renderer/render_pass.h"
@@ -97,7 +97,7 @@ EntityPass* EntityPass::AddSubpass(std::unique_ptr<EntityPass> pass) {
   return subpasses_.emplace_back(std::move(pass)).get();
 }
 
-bool EntityPass::Render(ContentRenderer& renderer,
+bool EntityPass::Render(ContentContext& renderer,
                         RenderPass& parent_pass) const {
   for (const auto& entity : entities_) {
     if (!entity.Render(renderer, parent_pass)) {

engine/src/flutter/impeller/entity/entity_pass.h

@@ -16,7 +16,7 @@
 
 namespace impeller {
 
-class ContentRenderer;
+class ContentContext;
 
 class EntityPass {
  public:
@@ -45,7 +45,7 @@ class EntityPass {
 
   EntityPass* GetSuperpass() const;
 
-  bool Render(ContentRenderer& renderer, RenderPass& parent_pass) const;
+  bool Render(ContentContext& renderer, RenderPass& parent_pass) const;
 
   void IterateAllEntities(std::function<bool(Entity&)> iterator);
 

engine/src/flutter/impeller/entity/entity_playground.cc

@@ -4,7 +4,7 @@
 
 #include "impeller/entity/entity_playground.h"
 
-#include "impeller/entity/content_renderer.h"
+#include "impeller/entity/content_context.h"
 
 namespace impeller {
 
@@ -13,12 +13,12 @@ EntityPlayground::EntityPlayground() = default;
 EntityPlayground::~EntityPlayground() = default;
 
 bool EntityPlayground::OpenPlaygroundHere(Entity entity) {
-  ContentRenderer renderer(GetContext());
-  if (!renderer.IsValid()) {
+  ContentContext context_context(GetContext());
+  if (!context_context.IsValid()) {
     return false;
   }
   Renderer::RenderCallback callback = [&](RenderPass& pass) -> bool {
-    return entity.Render(renderer, pass);
+    return entity.Render(context_context, pass);
   };
   return Playground::OpenPlaygroundHere(callback);
 }

engine/src/flutter/impeller/renderer/backend/metal/context_mtl.h

@@ -7,6 +7,7 @@
 #include <Metal/Metal.h>
 
 #include <string>
+#include <vector>
 
 #include "flutter/fml/macros.h"
 #include "impeller/renderer/backend/metal/allocator_mtl.h"

engine/src/flutter/impeller/renderer/renderer.cc

@@ -4,6 +4,8 @@
 
 #include "impeller/renderer/renderer.h"
 
+#include <algorithm>
+
 #include "flutter/fml/logging.h"
 #include "impeller/base/validation.h"
 #include "impeller/renderer/command_buffer.h"
@@ -11,11 +13,10 @@
 
 namespace impeller {
 
-constexpr size_t kMaxFramesInFlight = 3u;
-
-Renderer::Renderer(std::shared_ptr<Context> context)
-    : frames_in_flight_sema_(
-          std::make_shared<fml::Semaphore>(kMaxFramesInFlight)),
+Renderer::Renderer(std::shared_ptr<Context> context,
+                   size_t max_frames_in_flight)
+    : frames_in_flight_sema_(std::make_shared<fml::Semaphore>(
+          std::max<std::size_t>(1u, max_frames_in_flight))),
       context_(std::move(context)) {
   if (!context_->IsValid()) {
     return;

engine/src/flutter/impeller/renderer/renderer.h

@@ -10,7 +10,7 @@
 #include <memory>
 
 #include "flutter/fml/macros.h"
-#include "fml/synchronization/semaphore.h"
+#include "flutter/fml/synchronization/semaphore.h"
 #include "impeller/geometry/size.h"
 #include "impeller/renderer/context.h"
 
@@ -21,9 +21,12 @@ class RenderPass;
 
 class Renderer {
  public:
+  static constexpr size_t kDefaultMaxFramesInFlight = 3u;
+
   using RenderCallback = std::function<bool(RenderPass& pass)>;
 
-  Renderer(std::shared_ptr<Context> context);
+  Renderer(std::shared_ptr<Context> context,
+           size_t max_frames_in_flight = kDefaultMaxFramesInFlight);
 
   ~Renderer();