Add support for primitive types.

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

@@ -52,8 +52,8 @@ impeller_component("compositor") {
     "surface.mm",
     "texture.h",
     "texture.mm",
-    "vertex_buffer.h",
-    "vertex_buffer.mm",
+    "vertex_buffer_builder.h",
+    "vertex_buffer_builder.mm",
     "vertex_descriptor.h",
     "vertex_descriptor.mm",
   ]

engine/src/flutter/impeller/compositor/command.h

@@ -10,6 +10,7 @@
 
 #include "flutter/fml/macros.h"
 #include "impeller/compositor/buffer_view.h"
+#include "impeller/compositor/formats.h"
 #include "impeller/compositor/pipeline.h"
 
 namespace impeller {
@@ -30,6 +31,7 @@ struct Command {
   BufferView index_buffer;
   size_t index_count = 0u;
   std::string label;
+  PrimitiveType primitive_type;
 
   constexpr operator bool() const { return pipeline && pipeline->IsValid(); }
 };

engine/src/flutter/impeller/compositor/formats.h

@@ -56,6 +56,16 @@ enum class StoreAction {
   kStore,
 };
 
+enum class PrimitiveType {
+  kTriange,
+  kTriangeStrip,
+  kLine,
+  kLineStrip,
+  kPoint,
+  // Triangle fans are implementation dependent and need extra extensions
+  // checks. Hence, they are not supported here.
+};
+
 enum class ColorWriteMask : uint64_t {
   kNone = 0,
   kRed = 1 << 0,

engine/src/flutter/impeller/compositor/formats_metal.h

@@ -64,6 +64,22 @@ constexpr MTLBlendFactor ToMTLBlendFactor(BlendFactor type) {
   return MTLBlendFactorZero;
 };
 
+constexpr MTLPrimitiveType ToMTLPrimitiveType(PrimitiveType type) {
+  switch (type) {
+    case PrimitiveType::kTriange:
+      return MTLPrimitiveTypeTriangle;
+    case PrimitiveType::kTriangeStrip:
+      return MTLPrimitiveTypeTriangleStrip;
+    case PrimitiveType::kLine:
+      return MTLPrimitiveTypeLine;
+    case PrimitiveType::kLineStrip:
+      return MTLPrimitiveTypeLineStrip;
+    case PrimitiveType::kPoint:
+      return MTLPrimitiveTypePoint;
+  }
+  return MTLPrimitiveTypePoint;
+}
+
 constexpr MTLBlendOperation ToMTLBlendOperation(BlendOperation type) {
   switch (type) {
     case BlendOperation::kAdd:

engine/src/flutter/impeller/compositor/render_pass.mm

@@ -260,7 +260,7 @@ bool RenderPass::EncodeCommands(Allocator& allocator,
     }
     FML_DCHECK(command.index_count * sizeof(uint32_t) ==
                command.index_buffer.range.length);
-    [pass drawIndexedPrimitives:MTLPrimitiveTypeTriangleStrip
+    [pass drawIndexedPrimitives:ToMTLPrimitiveType(command.primitive_type)
                      indexCount:command.index_count
                       indexType:MTLIndexTypeUInt32
                     indexBuffer:mtl_index_buffer

engine/src/flutter/impeller/compositor/renderer.mm

@@ -53,6 +53,10 @@ bool Renderer::Render(const Surface& surface) {
     return false;
   }
 
+  if (!surface.Present()) {
+    return false;
+  }
+
   if (!render_pass->FinishEncoding(*GetContext()->GetTransientsAllocator())) {
     return false;
   }

engine/src/flutter/impeller/compositor/surface.h

@@ -6,6 +6,7 @@
 
 #include <Metal/Metal.h>
 
+#include <functional>
 #include <memory>
 
 #include "flutter/fml/macros.h"
@@ -16,16 +17,21 @@ namespace impeller {
 
 class Surface {
  public:
-  Surface(RenderPassDescriptor desc);
+  Surface(RenderPassDescriptor desc,
+          std::function<bool(void)> present_callback);
 
   ~Surface();
 
+  bool Present() const;
+
   bool IsValid() const;
 
   const RenderPassDescriptor& GetRenderPassDescriptor() const;
 
  private:
   RenderPassDescriptor desc_;
+  std::function<bool(void)> present_callback_;
+
   bool is_valid_ = false;
 
   FML_DISALLOW_COPY_AND_ASSIGN(Surface);

engine/src/flutter/impeller/compositor/surface.mm

@@ -8,7 +8,9 @@
 
 namespace impeller {
 
-Surface::Surface(RenderPassDescriptor desc) : desc_(std::move(desc)) {
+Surface::Surface(RenderPassDescriptor desc,
+                 std::function<bool(void)> present_callback)
+    : desc_(std::move(desc)), present_callback_(present_callback) {
   if (!desc_.HasColorAttachment(0)) {
     return;
   }
@@ -17,6 +19,16 @@ Surface::Surface(RenderPassDescriptor desc) : desc_(std::move(desc)) {
 
 Surface::~Surface() = default;
 
+bool Surface::Present() const {
+  auto callback = present_callback_;
+
+  if (!callback) {
+    return true;
+  }
+
+  return callback();
+}
+
 bool Surface::IsValid() const {
   return is_valid_;
 }

engine/src/flutter/impeller/compositor/vertex_buffer_builder.mm

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "impeller/compositor/vertex_buffer.h"
+#include "impeller/compositor/vertex_buffer_builder.h"
 
 namespace impeller {
 

engine/src/flutter/impeller/entity/entity_renderer.mm

@@ -3,8 +3,9 @@
 // found in the LICENSE file.
 
 #include "impeller/entity/entity_renderer.h"
+
 #include "impeller/compositor/command.h"
-#include "impeller/compositor/vertex_buffer.h"
+#include "impeller/compositor/vertex_buffer_builder.h"
 #include "impeller/primitives/box.frag.h"
 #include "impeller/primitives/box.vert.h"
 
@@ -40,23 +41,27 @@ bool EntityRenderer::OnRender(RenderPass& pass) {
 
   shader::BoxVertexInfo::UniformBuffer uniforms;
   uniforms.mvp = Matrix::MakeOrthographic({800, 600});
-  VertexBufferBuilder vertices;
-  vertices.AddVertices({
+  VertexBufferBuilder vertex_builder;
+  vertex_builder.AddVertices({
       {-0.5, 0.5, 1.0},   //
       {0.5, 0.5, 1.0},    //
       {0.5, -0.5, 1.0},   //
+      {0.5, -0.5, 1.0},   //
       {-0.5, -0.5, 1.0},  //
+      {-0.5, 0.5, 1.0},   //
   });
 
   Command cmd;
   cmd.label = "Box";
   cmd.pipeline = box_primitive_->GetPipeline();
   cmd.vertex_bindings.buffers[0u] =
-      vertices.CreateVertexBuffer(pass.GetTransientsBuffer());
+      vertex_builder.CreateVertexBuffer(pass.GetTransientsBuffer());
   cmd.vertex_bindings.buffers[1u] =
       pass.GetTransientsBuffer().EmplaceUniform(uniforms);
-  cmd.index_buffer = vertices.CreateIndexBuffer(pass.GetTransientsBuffer());
-  cmd.index_count = vertices.GetIndexCount();
+  cmd.index_buffer =
+      vertex_builder.CreateIndexBuffer(pass.GetTransientsBuffer());
+  cmd.index_count = vertex_builder.GetIndexCount();
+  cmd.primitive_type = PrimitiveType::kTriange;
   if (!pass.RecordCommand(std::move(cmd))) {
     return false;
   }

engine/src/flutter/impeller/host/impeller_renderer.mm

@@ -226,11 +226,15 @@ static const size_t kAlignedUniformsSize = (sizeof(Uniforms) & ~0xFF) + 0x100;
 
 - (void)drawInMTKView:(nonnull MTKView*)view {
   impeller::Surface surface(
-      impeller::FromMTLRenderPassDescriptor(view.currentRenderPassDescriptor));
+      impeller::FromMTLRenderPassDescriptor(view.currentRenderPassDescriptor),
+      [drawable = view.currentDrawable]() {
+        [drawable present];
+        return true;
+      });
   if (!renderer_->Render(surface)) {
     FML_LOG(ERROR) << "Could not render.";
   }
-
+  return;
   /// Per frame updates here
   dispatch_semaphore_wait(_inFlightSemaphore, DISPATCH_TIME_FOREVER);