[Impeller] Compute geometry for drawPoints in vertex shader, with fallback for optimized CPU routine.

ci/licenses_golden/licenses_flutter

@@ -1295,6 +1295,7 @@ ORIGIN: ../../../flutter/impeller/entity/shaders/gaussian_blur/gaussian_blur_alp
 ORIGIN: ../../../flutter/impeller/entity/shaders/gaussian_blur/gaussian_blur_alpha_nodecal.frag + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/entity/shaders/gaussian_blur/gaussian_blur_noalpha_decal.frag + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/entity/shaders/gaussian_blur/gaussian_blur_noalpha_nodecal.frag + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/entity/shaders/geometry/points.vert + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/entity/shaders/glyph_atlas.frag + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/entity/shaders/glyph_atlas.vert + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/entity/shaders/glyph_atlas_color.frag + ../../../flutter/LICENSE
@@ -3912,6 +3913,7 @@ FILE: ../../../flutter/impeller/entity/shaders/gaussian_blur/gaussian_blur_alpha
 FILE: ../../../flutter/impeller/entity/shaders/gaussian_blur/gaussian_blur_alpha_nodecal.frag
 FILE: ../../../flutter/impeller/entity/shaders/gaussian_blur/gaussian_blur_noalpha_decal.frag
 FILE: ../../../flutter/impeller/entity/shaders/gaussian_blur/gaussian_blur_noalpha_nodecal.frag
+FILE: ../../../flutter/impeller/entity/shaders/geometry/points.vert
 FILE: ../../../flutter/impeller/entity/shaders/glyph_atlas.frag
 FILE: ../../../flutter/impeller/entity/shaders/glyph_atlas.vert
 FILE: ../../../flutter/impeller/entity/shaders/glyph_atlas_color.frag

impeller/aiks/canvas.cc

@@ -383,6 +383,25 @@ void Canvas::RestoreClip() {
   GetCurrentPass().AddEntity(entity);
 }
 
+void Canvas::DrawPoints(std::vector<Point> points,
+                        Scalar radius,
+                        const Paint& paint,
+                        PointStyle point_style) {
+  if (radius <= 0) {
+    return;
+  }
+
+  Entity entity;
+  entity.SetTransformation(GetCurrentTransformation());
+  entity.SetStencilDepth(GetStencilDepth());
+  entity.SetBlendMode(paint.blend_mode);
+  entity.SetContents(paint.WithFilters(paint.CreateContentsForGeometry(
+      Geometry::MakePointField(std::move(points), radius,
+                               /*round=*/point_style == PointStyle::kRound))));
+
+  GetCurrentPass().AddEntity(entity);
+}
+
 void Canvas::DrawPicture(Picture picture) {
   if (!picture.pass) {
     return;

impeller/aiks/canvas.h

@@ -37,6 +37,14 @@ struct CanvasStackEntry {
   bool contains_clips = false;
 };
 
+enum class PointStyle {
+  /// @brief Points are drawn as squares.
+  kRound,
+
+  /// @brief Points are drawn as circles.
+  kSquare,
+};
+
 class Canvas {
  public:
   struct DebugOptions {
@@ -100,6 +108,11 @@ class Canvas {
 
   void DrawCircle(Point center, Scalar radius, const Paint& paint);
 
+  void DrawPoints(std::vector<Point>,
+                  Scalar radius,
+                  const Paint& paint,
+                  PointStyle point_style);
+
   void DrawImage(const std::shared_ptr<Image>& image,
                  Point offset,
                  const Paint& paint,

impeller/display_list/dl_dispatcher.cc

@@ -930,16 +930,17 @@ void DlDispatcher::drawPoints(PointMode mode,
   Paint paint = paint_;
   paint.style = Paint::Style::kStroke;
   switch (mode) {
-    case flutter::DlCanvas::PointMode::kPoints:
-      if (paint.stroke_cap == Cap::kButt) {
-        paint.stroke_cap = Cap::kSquare;
+    case flutter::DlCanvas::PointMode::kPoints: {
+      // Cap::kButt is also treated as a square.
+      auto point_style = paint.stroke_cap == Cap::kRound ? PointStyle::kRound
+                                                         : PointStyle::kSquare;
+      auto radius = paint.stroke_width;
+      if (radius > 0) {
+        radius /= 2.0;
       }
-      for (uint32_t i = 0; i < count; i++) {
-        Point p0 = skia_conversions::ToPoint(points[i]);
-        auto path = PathBuilder{}.AddLine(p0, p0).TakePath();
-        canvas_.DrawPath(path, paint);
-      }
-      break;
+      canvas_.DrawPoints(skia_conversions::ToPoints(points, count), radius,
+                         paint, point_style);
+    } break;
     case flutter::DlCanvas::PointMode::kLines:
       for (uint32_t i = 1; i < count; i += 2) {
         Point p0 = skia_conversions::ToPoint(points[i - 1]);

impeller/display_list/skia_conversions.cc

@@ -26,6 +26,14 @@ std::vector<Rect> ToRects(const SkRect tex[], int count) {
   return result;
 }
 
+std::vector<Point> ToPoints(const SkPoint points[], int count) {
+  std::vector<Point> result(count);
+  for (auto i = 0; i < count; i++) {
+    result[i] = ToPoint(points[i]);
+  }
+  return result;
+}
+
 PathBuilder::RoundingRadii ToRoundingRadii(const SkRRect& rrect) {
   using Corner = SkRRect::Corner;
   PathBuilder::RoundingRadii radii;

impeller/display_list/skia_conversions.h

@@ -26,6 +26,8 @@ std::optional<Rect> ToRect(const SkRect* rect);
 
 std::vector<Rect> ToRects(const SkRect tex[], int count);
 
+std::vector<Point> ToPoints(const SkPoint points[], int count);
+
 Point ToPoint(const SkPoint& point);
 
 Color ToColor(const SkColor& color);

impeller/entity/BUILD.gn

@@ -96,6 +96,7 @@ impeller_shaders("modern_entity_shaders") {
     "shaders/linear_gradient_ssbo_fill.frag",
     "shaders/radial_gradient_ssbo_fill.frag",
     "shaders/sweep_gradient_ssbo_fill.frag",
+    "shaders/geometry/points.vert",
   ]
 }
 

impeller/entity/contents/content_context.cc

@@ -144,6 +144,7 @@ void ContentContextOptions::ApplyToPipelineDescriptor(
   desc.SetPrimitiveType(primitive_type);
 
   desc.SetPolygonMode(wireframe ? PolygonMode::kLine : PolygonMode::kFill);
+  desc.SetEnableRasterization(enable_rasterization);
 }
 
 template <typename PipelineT>
@@ -161,6 +162,22 @@ static std::unique_ptr<PipelineT> CreateDefaultPipeline(
   return std::make_unique<PipelineT>(context, desc);
 }
 
+template <typename PipelineT>
+static std::unique_ptr<PipelineT> CreateDefaultNonRenderingPipeline(
+    const Context& context) {
+  auto desc = PipelineT::Builder::MakeDefaultPipelineDescriptor(context);
+  if (!desc.has_value()) {
+    return nullptr;
+  }
+  // Apply default ContentContextOptions to the descriptor.
+  const auto default_color_fmt =
+      context.GetCapabilities()->GetDefaultColorFormat();
+  ContentContextOptions{.color_attachment_pixel_format = default_color_fmt,
+                        .enable_rasterization = false}
+      .ApplyToPipelineDescriptor(*desc);
+  return std::make_unique<PipelineT>(context, desc);
+}
+
 ContentContext::ContentContext(std::shared_ptr<Context> context)
     : context_(std::move(context)),
       tessellator_(std::make_shared<Tessellator>()),
@@ -296,6 +313,12 @@ ContentContext::ContentContext(std::shared_ptr<Context> context)
   porter_duff_blend_pipelines_[{}] =
       CreateDefaultPipeline<PorterDuffBlendPipeline>(*context_);
 
+  if (context_->GetCapabilities()->SupportsDisabledRasterization()) {
+    point_field_geometry_pipelines_[{}] =
+        CreateDefaultNonRenderingPipeline<PointFieldGeometryPipeline>(
+            *context_);
+  }
+
   if (solid_fill_pipelines_[{}]->GetDescriptor().has_value()) {
     auto clip_pipeline_descriptor =
         solid_fill_pipelines_[{}]->GetDescriptor().value();

impeller/entity/contents/content_context.h

@@ -39,6 +39,7 @@
 #include "impeller/entity/linear_to_srgb_filter.vert.h"
 #include "impeller/entity/morphology_filter.frag.h"
 #include "impeller/entity/morphology_filter.vert.h"
+#include "impeller/entity/points.vert.h"
 #include "impeller/entity/porter_duff_blend.frag.h"
 #include "impeller/entity/radial_gradient_fill.frag.h"
 #include "impeller/entity/rrect_blur.frag.h"
@@ -275,6 +276,10 @@ using FramebufferBlendSoftLightPipeline =
     RenderPipelineT<FramebufferBlendVertexShader,
                     FramebufferBlendSoftlightFragmentShader>;
 
+/// Geometry Pipelines
+using PointFieldGeometryPipeline =
+    RenderPipelineT<PointsVertexShader, NonRenderingFragment>;
+
 /// Pipeline state configuration.
 ///
 /// Each unique combination of these options requires a different pipeline state
@@ -294,13 +299,14 @@ struct ContentContextOptions {
   std::optional<PixelFormat> color_attachment_pixel_format;
   bool has_stencil_attachment = true;
   bool wireframe = false;
+  bool enable_rasterization = true;
 
   struct Hash {
     constexpr std::size_t operator()(const ContentContextOptions& o) const {
-      return fml::HashCombine(o.sample_count, o.blend_mode, o.stencil_compare,
-                              o.stencil_operation, o.primitive_type,
-                              o.color_attachment_pixel_format,
-                              o.has_stencil_attachment, o.wireframe);
+      return fml::HashCombine(
+          o.sample_count, o.blend_mode, o.stencil_compare, o.stencil_operation,
+          o.primitive_type, o.color_attachment_pixel_format,
+          o.has_stencil_attachment, o.wireframe, o.enable_rasterization);
     }
   };
 
@@ -315,7 +321,8 @@ struct ContentContextOptions {
              lhs.color_attachment_pixel_format ==
                  rhs.color_attachment_pixel_format &&
              lhs.has_stencil_attachment == rhs.has_stencil_attachment &&
-             lhs.wireframe == rhs.wireframe;
+             lhs.wireframe == rhs.wireframe &&
+             lhs.enable_rasterization == rhs.enable_rasterization;
     }
   };
 
@@ -660,6 +667,12 @@ class ContentContext {
     return GetPipeline(framebuffer_blend_softlight_pipelines_, opts);
   }
 
+  std::shared_ptr<Pipeline<PipelineDescriptor>> GetPointFieldGeometryPipeline(
+      ContentContextOptions opts) const {
+    FML_DCHECK(GetDeviceCapabilities().SupportsDisabledRasterization());
+    return GetPipeline(point_field_geometry_pipelines_, opts);
+  }
+
   std::shared_ptr<Context> GetContext() const;
 
   std::shared_ptr<GlyphAtlasContext> GetGlyphAtlasContext(
@@ -783,6 +796,8 @@ class ContentContext {
   mutable Variants<FramebufferBlendSoftLightPipeline>
       framebuffer_blend_softlight_pipelines_;
 
+  mutable Variants<PointFieldGeometryPipeline> point_field_geometry_pipelines_;
+
   template <class TypedPipeline>
   std::shared_ptr<Pipeline<PipelineDescriptor>> GetPipeline(
       Variants<TypedPipeline>& container,