[Impeller] Copy user indices directly into buffer for DrawVertices (flutter#34792)

Author: bdero

display_list/display_list_vertices.h

@@ -108,7 +108,7 @@ class DlVertices {
     ///
     /// Vertices are always required. Optional texture coordinates
     /// and optional colors are reserved depending on the |Flags|.
-    /// Optional indices will be reserved iff the index_count is
+    /// Optional indices will be reserved if the index_count is
     /// positive (>0).
     ///
     /// The caller must provide all data that is promised by the

impeller/aiks/canvas.cc

@@ -306,11 +306,12 @@ void Canvas::DrawTextFrame(TextFrame text_frame, Point position, Paint paint) {
 }
 
 void Canvas::DrawVertices(Vertices vertices,
-                          Entity::BlendMode mode,
+                          Entity::BlendMode blend_mode,
                           Paint paint) {
   std::shared_ptr<VerticesContents> contents =
       std::make_shared<VerticesContents>(std::move(vertices));
   contents->SetColor(paint.color);
+  contents->SetBlendMode(blend_mode);
   Entity entity;
   entity.SetTransformation(GetCurrentTransformation());
   entity.SetStencilDepth(GetStencilDepth());

impeller/aiks/canvas.h

@@ -93,7 +93,9 @@ class Canvas {
 
   void DrawTextFrame(TextFrame text_frame, Point position, Paint paint);
 
-  void DrawVertices(Vertices vertices, Entity::BlendMode mode, Paint paint);
+  void DrawVertices(Vertices vertices,
+                    Entity::BlendMode blend_mode,
+                    Paint paint);
 
   Picture EndRecordingAsPicture();
 

impeller/entity/contents/vertices_contents.cc

@@ -12,6 +12,7 @@
 #include "impeller/renderer/formats.h"
 #include "impeller/renderer/render_pass.h"
 #include "impeller/renderer/sampler_library.h"
+#include "impeller/renderer/vertex_buffer.h"
 
 namespace impeller {
 
@@ -28,10 +29,27 @@ void VerticesContents::SetColor(Color color) {
   color_ = color.Premultiply();
 }
 
+void VerticesContents::SetBlendMode(Entity::BlendMode blend_mode) {
+  blend_mode_ = blend_mode;
+}
+
+static PrimitiveType GetPrimitiveType(const Vertices& vertices) {
+  switch (vertices.GetMode()) {
+    case VertexMode::kTriangle:
+      return PrimitiveType::kTriangle;
+    case VertexMode::kTriangleStrip:
+      return PrimitiveType::kTriangleStrip;
+  }
+}
+
 bool VerticesContents::Render(const ContentContext& renderer,
                               const Entity& entity,
                               RenderPass& pass) const {
-  using VS = VerticesVertexShader;
+  if (!vertices_.IsValid()) {
+    return true;
+  }
+
+  using VS = VerticesPipeline::VertexShader;
 
   const auto coverage_rect = vertices_.GetBoundingBox();
 
@@ -43,42 +61,36 @@ bool VerticesContents::Render(const ContentContext& renderer,
     return true;
   }
 
-  VertexBufferBuilder<VS::PerVertexData> vertex_builder;
-  std::vector<Point> points = vertices_.GetPoints();
-  std::vector<uint16_t> indices = vertices_.GetIndices();
-  // TODO: colors are currently unused, must be blended with
-  // paint color based on provided blend mode.
-  std::vector<Color> colors = vertices_.GetColors();
-  VertexMode mode = vertices_.GetMode();
-
-  if (indices.size() == 0) {
-    for (size_t i = 0; i < points.size(); i += 1) {
-      VS::PerVertexData data;
-      data.point = points[i];
-      data.vertex_color = color_;
-      vertex_builder.AppendVertex(data);
-    }
-  } else {
-    for (size_t i = 0; i < indices.size(); i += 1) {
-      VS::PerVertexData data;
-      data.point = points[indices[i]];
-      data.vertex_color = color_;
-      vertex_builder.AppendVertex(data);
+  std::vector<VS::PerVertexData> vertex_data;
+  {
+    const auto& positions = vertices_.GetPositions();
+    const auto& colors = vertices_.GetColors();
+    for (size_t i = 0; i < positions.size(); i++) {
+      vertex_data.push_back(VS::PerVertexData{
+          .position = positions[i],
+          // TODO(108047): Blend these colors together when available. Use
+          //               colors[i] as the destination and color_ as the
+          //               source. Always use color_ when vertex colors are not
+          //               supplied.
+          .color = i < colors.size() ? colors[i] : color_,
+      });
     }
   }
 
-  PrimitiveType primitiveType;
-  switch (mode) {
-    case VertexMode::kTriangle:
-      primitiveType = PrimitiveType::kTriangle;
-      break;
-    case VertexMode::kTriangleStrip:
-      primitiveType = PrimitiveType::kTriangleStrip;
-      break;
-  }
+  size_t total_vtx_bytes = vertex_data.size() * sizeof(VS::PerVertexData);
+  size_t total_idx_bytes = vertices_.GetIndices().size() * sizeof(uint16_t);
 
-  if (!vertex_builder.HasVertices()) {
-    return true;
+  auto buffer = renderer.GetContext()->GetTransientsAllocator()->CreateBuffer(
+      StorageMode::kHostVisible, total_vtx_bytes + total_idx_bytes);
+
+  if (!buffer->CopyHostBuffer(reinterpret_cast<uint8_t*>(vertex_data.data()),
+                              Range{0, total_vtx_bytes}, 0)) {
+    return false;
+  }
+  if (!buffer->CopyHostBuffer(reinterpret_cast<uint8_t*>(const_cast<uint16_t*>(
+                                  vertices_.GetIndices().data())),
+                              Range{0, total_idx_bytes}, total_vtx_bytes)) {
+    return false;
   }
 
   auto& host_buffer = pass.GetTransientsBuffer();
@@ -91,8 +103,14 @@ bool VerticesContents::Render(const ContentContext& renderer,
   cmd.pipeline =
       renderer.GetVerticesPipeline(OptionsFromPassAndEntity(pass, entity));
   cmd.stencil_reference = entity.GetStencilDepth();
-  cmd.primitive_type = primitiveType;
-  cmd.BindVertices(vertex_builder.CreateVertexBuffer(host_buffer));
+  cmd.primitive_type = GetPrimitiveType(vertices_);
+  cmd.BindVertices({
+      .vertex_buffer = {.buffer = buffer, .range = Range{0, total_vtx_bytes}},
+      .index_buffer = {.buffer = buffer,
+                       .range = Range{total_vtx_bytes, total_idx_bytes}},
+      .index_count = vertices_.GetIndices().size(),
+      .index_type = IndexType::k16bit,
+  });
   VS::BindFrameInfo(cmd, host_buffer.EmplaceUniform(frame_info));
   pass.AddCommand(std::move(cmd));
 

impeller/entity/contents/vertices_contents.h

@@ -10,6 +10,7 @@
 
 #include "flutter/fml/macros.h"
 #include "impeller/entity/contents/contents.h"
+#include "impeller/entity/entity.h"
 #include "impeller/geometry/color.h"
 #include "impeller/geometry/path.h"
 #include "impeller/geometry/point.h"
@@ -26,6 +27,8 @@ class VerticesContents final : public Contents {
 
   void SetColor(Color color);
 
+  void SetBlendMode(Entity::BlendMode blend_mode);
+
   // |Contents|
   std::optional<Rect> GetCoverage(const Entity& entity) const override;
 
@@ -37,6 +40,7 @@ class VerticesContents final : public Contents {
  public:
   Vertices vertices_;
   Color color_;
+  Entity::BlendMode blend_mode_ = Entity::BlendMode::kSource;
 
   FML_DISALLOW_COPY_AND_ASSIGN(VerticesContents);
 };

impeller/entity/entity_unittests.cc

@@ -1055,14 +1055,31 @@ TEST_P(EntityTest, BorderMaskBlurCoverageIsCorrect) {
   }
 }
 
-TEST_P(EntityTest, DrawVerticesSolidColorTrianglesWithoutIndex) {
-  std::vector<Point> points = {Point(100, 300), Point(200, 100),
-                               Point(300, 300)};
-  std::vector<uint16_t> indexes;
+TEST_P(EntityTest, DrawVerticesSolidColorTrianglesWithoutIndices) {
+  std::vector<Point> positions = {Point(100, 300), Point(200, 100),
+                                  Point(300, 300)};
   std::vector<Color> colors = {Color::White(), Color::White(), Color::White()};
 
-  Vertices vertices = Vertices(points, indexes, colors, VertexMode::kTriangle,
-                               Rect(100, 100, 300, 300));
+  Vertices vertices = Vertices(positions, {} /* indices */, colors,
+                               VertexMode::kTriangle, Rect(100, 100, 300, 300));
+
+  std::shared_ptr<VerticesContents> contents =
+      std::make_shared<VerticesContents>(vertices);
+  contents->SetColor(Color::White());
+  Entity e;
+  e.SetTransformation(Matrix::MakeScale(GetContentScale()));
+  e.SetContents(contents);
+
+  ASSERT_TRUE(OpenPlaygroundHere(e));
+}
+
+TEST_P(EntityTest, DrawVerticesSolidColorTrianglesWithIndices) {
+  std::vector<Point> positions = {Point(100, 300), Point(200, 100),
+                                  Point(300, 300), Point(200, 500)};
+  std::vector<uint16_t> indices = {0, 1, 2, 0, 2, 3};
+
+  Vertices vertices = Vertices(positions, indices, {} /* colors */,
+                               VertexMode::kTriangle, Rect(100, 100, 300, 300));
 
   std::shared_ptr<VerticesContents> contents =
       std::make_shared<VerticesContents>(vertices);

impeller/entity/shaders/vertices.frag

@@ -2,10 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-in vec4 color;
+in vec4 v_color;
 
 out vec4 frag_color;
 
 void main() {
-  frag_color = color;
+  frag_color = v_color;
 }

impeller/entity/shaders/vertices.vert

@@ -6,12 +6,12 @@ uniform FrameInfo {
   mat4 mvp;
 } frame_info;
 
-in vec2 point;
-in vec4 vertex_color;
+in vec2 position;
+in vec4 color;
 
-out vec4 color;
+out vec4 v_color;
 
 void main() {
-  gl_Position = frame_info.mvp * vec4(point, 0.0, 1.0);
-  color = vertex_color;
+  gl_Position = frame_info.mvp * vec4(position, 0.0, 1.0);
+  v_color = color;
 }

impeller/geometry/geometry_unittests.cc

@@ -1233,7 +1233,7 @@ TEST(GeometryTest, VerticesConstructorAndGetters) {
                                Rect(0, 0, 4, 4));
 
   ASSERT_EQ(vertices.GetBoundingBox().value(), Rect(0, 0, 4, 4));
-  ASSERT_EQ(vertices.GetPoints(), points);
+  ASSERT_EQ(vertices.GetPositions(), points);
   ASSERT_EQ(vertices.GetIndices(), indices);
   ASSERT_EQ(vertices.GetColors(), colors);
   ASSERT_EQ(vertices.GetMode(), VertexMode::kTriangle);

impeller/geometry/vertices.cc

@@ -11,14 +11,31 @@ Vertices::Vertices(std::vector<Point> points,
                    std::vector<Color> colors,
                    VertexMode vertex_mode,
                    Rect bounds)
-    : points_(std::move(points)),
+    : positions_(std::move(points)),
       indices_(std::move(indices)),
       colors_(std::move(colors)),
       vertex_mode_(vertex_mode),
-      bounds_(bounds){};
+      bounds_(bounds) {
+  NormalizeIndices();
+}
 
 Vertices::~Vertices() = default;
 
+bool Vertices::IsValid() const {
+  size_t points_size = positions_.size();
+  size_t colors_size = colors_.size();
+
+  if (colors_size > 0 && colors_size != points_size) {
+    return false;
+  }
+
+  return true;
+}
+
+std::optional<Rect> Vertices::GetBoundingBox() const {
+  return bounds_;
+};
+
 std::optional<Rect> Vertices::GetTransformedBoundingBox(
     const Matrix& transform) const {
   auto bounds = GetBoundingBox();
@@ -28,4 +45,29 @@ std::optional<Rect> Vertices::GetTransformedBoundingBox(
   return bounds->TransformBounds(transform);
 };
 
+const std::vector<Point>& Vertices::GetPositions() const {
+  return positions_;
+}
+
+const std::vector<uint16_t>& Vertices::GetIndices() const {
+  return indices_;
+}
+
+const std::vector<Color>& Vertices::GetColors() const {
+  return colors_;
+}
+
+VertexMode Vertices::GetMode() const {
+  return vertex_mode_;
+}
+
+void Vertices::NormalizeIndices() {
+  if (indices_.size() != 0 || positions_.size() == 0) {
+    return;
+  }
+  for (size_t i = 0; i < positions_.size(); i++) {
+    indices_.push_back(i);
+  }
+}
+
 }  // namespace impeller