Make pipelines store pipeline descriptors.

Author: chinmaygarde

impeller/renderer/backend/metal/context_mtl.h

@@ -61,6 +61,12 @@ class ContextMTL final : public Context,
   // |Context|
   std::shared_ptr<CommandBuffer> CreateRenderCommandBuffer() const override;
 
+  // |Context|
+  std::shared_ptr<CommandBuffer> CreateTransferCommandBuffer() const override;
+
+  std::shared_ptr<CommandBuffer> CreateCommandBufferInQueue(
+      id<MTLCommandQueue> queue) const;
+
   FML_DISALLOW_COPY_AND_ASSIGN(ContextMTL);
 };
 

impeller/renderer/backend/metal/context_mtl.mm

@@ -108,12 +108,20 @@
 }
 
 std::shared_ptr<CommandBuffer> ContextMTL::CreateRenderCommandBuffer() const {
+  return CreateCommandBufferInQueue(render_queue_);
+}
+
+std::shared_ptr<CommandBuffer> ContextMTL::CreateTransferCommandBuffer() const {
+  return CreateCommandBufferInQueue(transfer_queue_);
+}
+
+std::shared_ptr<CommandBuffer> ContextMTL::CreateCommandBufferInQueue(
+    id<MTLCommandQueue> queue) const {
   if (!IsValid()) {
     return nullptr;
   }
 
-  auto buffer =
-      std::shared_ptr<CommandBufferMTL>(new CommandBufferMTL(render_queue_));
+  auto buffer = std::shared_ptr<CommandBufferMTL>(new CommandBufferMTL(queue));
   if (!buffer->IsValid()) {
     return nullptr;
   }

impeller/renderer/backend/metal/pipeline_library_mtl.mm

@@ -77,6 +77,11 @@
     return future;
   }
 
+  // TODO(csg): There is a bug here where multiple calls to GetRenderPipeline
+  // will result in multiple render pipelines of the same descriptor being
+  // created till the first instance of the creation invokes its completion
+  // callback.
+
   auto thiz = shared_from_this();
 
   auto completion_handler =
@@ -88,8 +93,10 @@
           promise->set_value(nullptr);
         } else {
           auto new_pipeline = std::shared_ptr<PipelineMTL>(new PipelineMTL(
-              render_pipeline_state,
-              CreateDepthStencilDescriptor(descriptor, device_)));
+              descriptor,                                        //
+              render_pipeline_state,                             //
+              CreateDepthStencilDescriptor(descriptor, device_)  //
+              ));
           promise->set_value(new_pipeline);
           this->SavePipeline(descriptor, new_pipeline);
         }

impeller/renderer/backend/metal/pipeline_mtl.h

@@ -30,7 +30,8 @@ class PipelineMTL final : public Pipeline,
   id<MTLDepthStencilState> depth_stencil_state_;
   bool is_valid_ = false;
 
-  PipelineMTL(id<MTLRenderPipelineState> state,
+  PipelineMTL(PipelineDescriptor desc,
+              id<MTLRenderPipelineState> state,
               id<MTLDepthStencilState> depth_stencil_state);
 
   // |PipelineMTL|

impeller/renderer/backend/metal/pipeline_mtl.mm

@@ -6,9 +6,12 @@
 
 namespace impeller {
 
-PipelineMTL::PipelineMTL(id<MTLRenderPipelineState> state,
+PipelineMTL::PipelineMTL(PipelineDescriptor desc,
+                         id<MTLRenderPipelineState> state,
                          id<MTLDepthStencilState> depth_stencil_state)
-    : pipeline_state_(state), depth_stencil_state_(depth_stencil_state) {
+    : Pipeline(std::move(desc)),
+      pipeline_state_(state),
+      depth_stencil_state_(depth_stencil_state) {
   if (!pipeline_state_) {
     return;
   }

impeller/renderer/context.h

@@ -43,6 +43,9 @@ class Context {
 
   virtual std::shared_ptr<CommandBuffer> CreateRenderCommandBuffer() const = 0;
 
+  virtual std::shared_ptr<CommandBuffer> CreateTransferCommandBuffer()
+      const = 0;
+
  protected:
   Context();
 

impeller/renderer/pipeline.cc

@@ -9,7 +9,7 @@
 
 namespace impeller {
 
-Pipeline::Pipeline() = default;
+Pipeline::Pipeline(PipelineDescriptor desc) : desc_(std::move(desc)) {}
 
 Pipeline::~Pipeline() = default;
 
@@ -25,4 +25,8 @@ PipelineFuture CreatePipelineFuture(const Context& context,
   return context.GetPipelineLibrary()->GetRenderPipeline(std::move(desc));
 }
 
+const PipelineDescriptor& Pipeline::GetDescriptor() const {
+  return desc_;
+}
+
 }  // namespace impeller

impeller/renderer/pipeline.h

@@ -42,10 +42,14 @@ class Pipeline {
 
   virtual bool IsValid() const = 0;
 
+  const PipelineDescriptor& GetDescriptor() const;
+
  protected:
-  Pipeline();
+  Pipeline(PipelineDescriptor desc);
 
  private:
+  const PipelineDescriptor desc_;
+
   FML_DISALLOW_COPY_AND_ASSIGN(Pipeline);
 };