From 9ac0765bb8a0ee32db8ce916a02c7282ebbb1bcb Mon Sep 17 00:00:00 2001
From: jonahwilliams <jonahwilliams@google.com>
Date: Wed, 14 Aug 2024 15:30:45 -0700
Subject: [PATCH 01/10] [Impeller] add support for rectellipse.

---
 impeller/aiks/aiks_unittests.cc               | 25 +++++
 impeller/aiks/canvas.cc                       | 16 ++++
 impeller/aiks/canvas.h                        |  6 ++
 impeller/entity/BUILD.gn                      |  2 +
 .../entity/geometry/rectellipse_geometry.cc   | 94 +++++++++++++++++++
 .../entity/geometry/rectellipse_geometry.h    | 49 ++++++++++
 6 files changed, 192 insertions(+)
 create mode 100644 impeller/entity/geometry/rectellipse_geometry.cc
 create mode 100644 impeller/entity/geometry/rectellipse_geometry.h

diff --git a/impeller/aiks/aiks_unittests.cc b/impeller/aiks/aiks_unittests.cc
index cc36718db17bd..ceff44219267e 100644
--- a/impeller/aiks/aiks_unittests.cc
+++ b/impeller/aiks/aiks_unittests.cc
@@ -486,6 +486,31 @@ TEST_P(AiksTest, CorrectClipDepthAssignedToEntities) {
   }
 }
 
+TEST_P(AiksTest, DrawSuperEllipse) {
+  auto callback = [&](AiksContext& renderer) -> std::optional<Picture> {
+    // UI state.
+    static float alpha = 1;
+    static float beta = 1;
+    static float radius = 40;
+    static Color color = Color::Red();
+
+    if (AiksTest::ImGuiBegin("Controls", nullptr,
+                             ImGuiWindowFlags_AlwaysAutoResize)) {
+      ImGui::SliderFloat("Alpha", &alpha, 0, 100);
+      ImGui::SliderFloat("Beta", &beta, 0, 100);
+      ImGui::SliderFloat("Radius", &radius, 0, 400);
+      ImGui::ColorEdit4("Color", reinterpret_cast<float*>(&color));
+      ImGui::End();
+    }
+
+    Canvas canvas;
+    canvas.DrawSuperEllipse({400, 400}, radius, alpha, beta, {.color = color});
+    return canvas.EndRecordingAsPicture();
+  };
+
+  OpenPlaygroundHere(callback);
+}
+
 }  // namespace testing
 }  // namespace impeller
 
diff --git a/impeller/aiks/canvas.cc b/impeller/aiks/canvas.cc
index a1a5704736260..80222703c51f0 100644
--- a/impeller/aiks/canvas.cc
+++ b/impeller/aiks/canvas.cc
@@ -23,6 +23,7 @@
 #include "impeller/entity/contents/texture_contents.h"
 #include "impeller/entity/contents/vertices_contents.h"
 #include "impeller/entity/geometry/geometry.h"
+#include "impeller/entity/geometry/rectellipse_geometry.h"
 #include "impeller/geometry/color.h"
 #include "impeller/geometry/constants.h"
 #include "impeller/geometry/path_builder.h"
@@ -846,6 +847,21 @@ void Canvas::SaveLayer(const Paint& paint,
   new_layer_pass.SetDelegate(std::make_shared<PaintPassDelegate>(paint_copy));
 }
 
+void Canvas::DrawSuperEllipse(Point center,
+                              Scalar radius,
+                              Scalar alpha,
+                              Scalar beta,
+                              const Paint& paint) {
+  Entity entity;
+  entity.SetTransform(GetCurrentTransform());
+  entity.SetBlendMode(paint.blend_mode);
+  entity.SetContents(CreateContentsForGeometryWithFilters(
+      paint,
+      std::make_shared<RectellipseGeometry>(center, radius, alpha, beta)));
+
+  AddRenderEntityToCurrentPass(std::move(entity));
+}
+
 void Canvas::DrawTextFrame(const std::shared_ptr<TextFrame>& text_frame,
                            Point position,
                            const Paint& paint) {
diff --git a/impeller/aiks/canvas.h b/impeller/aiks/canvas.h
index e5bdc379b0622..77ea4ad9a4a29 100644
--- a/impeller/aiks/canvas.h
+++ b/impeller/aiks/canvas.h
@@ -133,6 +133,12 @@ class Canvas {
                  const Paint& paint,
                  SamplerDescriptor sampler = {});
 
+  void DrawSuperEllipse(Point center,
+                        Scalar radius,
+                        Scalar alpha,
+                        Scalar beta,
+                        const Paint& paint);
+
   void DrawImageRect(
       const std::shared_ptr<Image>& image,
       Rect source,
diff --git a/impeller/entity/BUILD.gn b/impeller/entity/BUILD.gn
index d91d56cdfe5fe..46a2cbaa67e1b 100644
--- a/impeller/entity/BUILD.gn
+++ b/impeller/entity/BUILD.gn
@@ -192,6 +192,8 @@ impeller_component("entity") {
     "geometry/point_field_geometry.h",
     "geometry/rect_geometry.cc",
     "geometry/rect_geometry.h",
+    "geometry/rectellipse_geometry.cc",
+    "geometry/rectellipse_geometry.h",
     "geometry/round_rect_geometry.cc",
     "geometry/round_rect_geometry.h",
     "geometry/stroke_path_geometry.cc",
diff --git a/impeller/entity/geometry/rectellipse_geometry.cc b/impeller/entity/geometry/rectellipse_geometry.cc
new file mode 100644
index 0000000000000..5a339d77a4395
--- /dev/null
+++ b/impeller/entity/geometry/rectellipse_geometry.cc
@@ -0,0 +1,94 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <vector>
+
+#include "flutter/impeller/entity/geometry/rectellipse_geometry.h"
+
+#include "impeller/geometry/constants.h"
+
+namespace impeller {
+
+RectellipseGeometry::RectellipseGeometry(const Point& center,
+                                         Scalar radius,
+                                         Scalar alpha,
+                                         Scalar beta,
+                                         Scalar n)
+    : center_(center), radius_(radius), alpha_(alpha), beta_(beta), n_(n) {}
+
+GeometryResult RectellipseGeometry::GetPositionBuffer(
+    const ContentContext& renderer,
+    const Entity& entity,
+    RenderPass& pass) const {
+  // https://math.stackexchange.com/questions/2573746/superellipse-parametric-equation
+  Scalar a = alpha_;
+  Scalar b = beta_;
+  Scalar n = 4;
+
+  // TODO(jonahwilliams): determine parameter values based on scaling factor.
+  Scalar step = kPi / 80;
+
+  // Generate the points for the top left quadrant, and then mirror to the other
+  // quadrants.
+  std::vector<Point> points;
+  for (Scalar t = 0; t < (kPi / 2) - step; t += step) {
+    Scalar x = a * pow(abs(cos(t)), 2 / n);
+    Scalar y = b * pow(abs(sin(t)), 2 / n);
+    points.emplace_back(x, y);
+  }
+  Scalar x = a * pow(abs(cos(kPi / 2)), 2 / n);
+  Scalar y = b * pow(abs(sin(kPi / 2)), 2 / n);
+  points.emplace_back(x, y);
+
+  // Reflect into the other 3 quadrants and generate the tessellated mesh.
+  std::vector<Point> geometry;
+  static constexpr Point reflection[4] = {{1, 1}, {-1, 1}, {-1, -1}, {1, -1}};
+
+  geometry.push_back(center_);
+  for (auto sc : reflection) {
+    for (auto pt : points) {
+      geometry.push_back(center_ + ((sc * pt) * radius_));
+    }
+  }
+
+  std::vector<uint16_t> indices;
+  for (auto i = 2u; i < geometry.size(); i++) {
+    indices.push_back(0);
+    indices.push_back(i - 1);
+    indices.push_back(i);
+  }
+
+  auto& host_buffer = renderer.GetTransientsBuffer();
+  return GeometryResult{
+      .type = PrimitiveType::kTriangle,
+      .vertex_buffer =
+          {
+              .vertex_buffer = host_buffer.Emplace(
+                  geometry.data(), geometry.size() * sizeof(Point),
+                  alignof(Point)),
+              .index_buffer = host_buffer.Emplace(
+                  indices.data(), indices.size() * sizeof(uint16_t),
+                  alignof(uint16_t)),
+              .vertex_count = indices.size(),
+              .index_type = IndexType::k16bit,
+          },
+      .transform = entity.GetShaderTransform(pass),
+  };
+}
+
+std::optional<Rect> RectellipseGeometry::GetCoverage(
+    const Matrix& transform) const {
+  return Rect::MakeMaximum();
+}
+
+bool RectellipseGeometry::CoversArea(const Matrix& transform,
+                                     const Rect& rect) const {
+  return false;
+}
+
+bool RectellipseGeometry::IsAxisAlignedRect() const {
+  return false;
+}
+
+}  // namespace impeller
diff --git a/impeller/entity/geometry/rectellipse_geometry.h b/impeller/entity/geometry/rectellipse_geometry.h
new file mode 100644
index 0000000000000..dc862f1d9eb0d
--- /dev/null
+++ b/impeller/entity/geometry/rectellipse_geometry.h
@@ -0,0 +1,49 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef FLUTTER_IMPELLER_ENTITY_GEOMETRY_RECTELLIPSE_GEOMETRY_H_
+#define FLUTTER_IMPELLER_ENTITY_GEOMETRY_RECTELLIPSE_GEOMETRY_H_
+
+#include "impeller/entity/geometry/geometry.h"
+
+namespace impeller {
+
+// Geometry class that can generate vertices for a rectellipse.
+class RectellipseGeometry final : public Geometry {
+ public:
+  explicit RectellipseGeometry(const Point& center,
+                               Scalar radius,
+                               Scalar alpha,
+                               Scalar beta);
+
+  ~RectellipseGeometry() = default;
+
+  // |Geometry|
+  bool CoversArea(const Matrix& transform, const Rect& rect) const override;
+
+  // |Geometry|
+  bool IsAxisAlignedRect() const override;
+
+ private:
+  // |Geometry|
+  GeometryResult GetPositionBuffer(const ContentContext& renderer,
+                                   const Entity& entity,
+                                   RenderPass& pass) const override;
+
+  // |Geometry|
+  std::optional<Rect> GetCoverage(const Matrix& transform) const override;
+
+  Point center_;
+  Scalar radius_;
+  Scalar alpha_;
+  Scalar beta_;
+
+  RectellipseGeometry(const RectellipseGeometry&) = delete;
+
+  RectellipseGeometry& operator=(const RectellipseGeometry&) = delete;
+};
+
+}  // namespace impeller
+
+#endif  // FLUTTER_IMPELLER_ENTITY_GEOMETRY_RECTELLIPSE_GEOMETRY_H_

From ffddf05f2d46bcb33140b440c6567a2745b36c51 Mon Sep 17 00:00:00 2001
From: jonahwilliams <jonahwilliams@google.com>
Date: Wed, 14 Aug 2024 17:04:44 -0700
Subject: [PATCH 02/10] full configuration.

---
 impeller/aiks/aiks_unittests.cc               | 14 ++++-
 impeller/aiks/canvas.cc                       |  9 +--
 impeller/aiks/canvas.h                        |  3 +-
 impeller/entity/BUILD.gn                      |  4 +-
 ...e_geometry.cc => superellipse_geometry.cc} | 60 ++++++++++++-------
 ...pse_geometry.h => superellipse_geometry.h} | 27 +++++----
 6 files changed, 75 insertions(+), 42 deletions(-)
 rename impeller/entity/geometry/{rectellipse_geometry.cc => superellipse_geometry.cc} (54%)
 rename impeller/entity/geometry/{rectellipse_geometry.h => superellipse_geometry.h} (51%)

diff --git a/impeller/aiks/aiks_unittests.cc b/impeller/aiks/aiks_unittests.cc
index ceff44219267e..e84b3cf37e71c 100644
--- a/impeller/aiks/aiks_unittests.cc
+++ b/impeller/aiks/aiks_unittests.cc
@@ -489,22 +489,30 @@ TEST_P(AiksTest, CorrectClipDepthAssignedToEntities) {
 TEST_P(AiksTest, DrawSuperEllipse) {
   auto callback = [&](AiksContext& renderer) -> std::optional<Picture> {
     // UI state.
-    static float alpha = 1;
-    static float beta = 1;
+    static float alpha = 10;
+    static float beta = 10;
     static float radius = 40;
+    static int degree = 4;
     static Color color = Color::Red();
 
     if (AiksTest::ImGuiBegin("Controls", nullptr,
                              ImGuiWindowFlags_AlwaysAutoResize)) {
       ImGui::SliderFloat("Alpha", &alpha, 0, 100);
       ImGui::SliderFloat("Beta", &beta, 0, 100);
+      ImGui::SliderInt("Degreee", &degree, 1, 20);
       ImGui::SliderFloat("Radius", &radius, 0, 400);
       ImGui::ColorEdit4("Color", reinterpret_cast<float*>(&color));
       ImGui::End();
     }
 
     Canvas canvas;
-    canvas.DrawSuperEllipse({400, 400}, radius, alpha, beta, {.color = color});
+    canvas.DrawSuperellipse(
+        /*center=*/{400, 400},
+        /*radius=*/radius,
+        /*degree=*/degree,
+        /*alpha=*/alpha,
+        /*beta=*/beta,
+        /*paint=*/{.color = color});
     return canvas.EndRecordingAsPicture();
   };
 
diff --git a/impeller/aiks/canvas.cc b/impeller/aiks/canvas.cc
index 80222703c51f0..c8860043bf972 100644
--- a/impeller/aiks/canvas.cc
+++ b/impeller/aiks/canvas.cc
@@ -23,7 +23,7 @@
 #include "impeller/entity/contents/texture_contents.h"
 #include "impeller/entity/contents/vertices_contents.h"
 #include "impeller/entity/geometry/geometry.h"
-#include "impeller/entity/geometry/rectellipse_geometry.h"
+#include "impeller/entity/geometry/superellipse_geometry.h"
 #include "impeller/geometry/color.h"
 #include "impeller/geometry/constants.h"
 #include "impeller/geometry/path_builder.h"
@@ -847,8 +847,9 @@ void Canvas::SaveLayer(const Paint& paint,
   new_layer_pass.SetDelegate(std::make_shared<PaintPassDelegate>(paint_copy));
 }
 
-void Canvas::DrawSuperEllipse(Point center,
+void Canvas::DrawSuperellipse(Point center,
                               Scalar radius,
+                              int degree,
                               Scalar alpha,
                               Scalar beta,
                               const Paint& paint) {
@@ -856,8 +857,8 @@ void Canvas::DrawSuperEllipse(Point center,
   entity.SetTransform(GetCurrentTransform());
   entity.SetBlendMode(paint.blend_mode);
   entity.SetContents(CreateContentsForGeometryWithFilters(
-      paint,
-      std::make_shared<RectellipseGeometry>(center, radius, alpha, beta)));
+      paint, std::make_shared<SuperellipseGeometry>(center, radius, degree,
+                                                    alpha, beta)));
 
   AddRenderEntityToCurrentPass(std::move(entity));
 }
diff --git a/impeller/aiks/canvas.h b/impeller/aiks/canvas.h
index 77ea4ad9a4a29..11ee307247e1e 100644
--- a/impeller/aiks/canvas.h
+++ b/impeller/aiks/canvas.h
@@ -133,8 +133,9 @@ class Canvas {
                  const Paint& paint,
                  SamplerDescriptor sampler = {});
 
-  void DrawSuperEllipse(Point center,
+  void DrawSuperellipse(Point center,
                         Scalar radius,
+                        int degree,
                         Scalar alpha,
                         Scalar beta,
                         const Paint& paint);
diff --git a/impeller/entity/BUILD.gn b/impeller/entity/BUILD.gn
index 46a2cbaa67e1b..98e5831ac0ee6 100644
--- a/impeller/entity/BUILD.gn
+++ b/impeller/entity/BUILD.gn
@@ -192,12 +192,12 @@ impeller_component("entity") {
     "geometry/point_field_geometry.h",
     "geometry/rect_geometry.cc",
     "geometry/rect_geometry.h",
-    "geometry/rectellipse_geometry.cc",
-    "geometry/rectellipse_geometry.h",
     "geometry/round_rect_geometry.cc",
     "geometry/round_rect_geometry.h",
     "geometry/stroke_path_geometry.cc",
     "geometry/stroke_path_geometry.h",
+    "geometry/superellipse_geometry.cc",
+    "geometry/superellipse_geometry.h",
     "geometry/vertices_geometry.cc",
     "geometry/vertices_geometry.h",
     "inline_pass_context.cc",
diff --git a/impeller/entity/geometry/rectellipse_geometry.cc b/impeller/entity/geometry/superellipse_geometry.cc
similarity index 54%
rename from impeller/entity/geometry/rectellipse_geometry.cc
rename to impeller/entity/geometry/superellipse_geometry.cc
index 5a339d77a4395..14418fe7f49f5 100644
--- a/impeller/entity/geometry/rectellipse_geometry.cc
+++ b/impeller/entity/geometry/superellipse_geometry.cc
@@ -4,27 +4,31 @@
 
 #include <vector>
 
-#include "flutter/impeller/entity/geometry/rectellipse_geometry.h"
+#include "flutter/impeller/entity/geometry/superellipse_geometry.h"
 
 #include "impeller/geometry/constants.h"
 
 namespace impeller {
 
-RectellipseGeometry::RectellipseGeometry(const Point& center,
-                                         Scalar radius,
-                                         Scalar alpha,
-                                         Scalar beta,
-                                         Scalar n)
-    : center_(center), radius_(radius), alpha_(alpha), beta_(beta), n_(n) {}
-
-GeometryResult RectellipseGeometry::GetPositionBuffer(
+SuperellipseGeometry::SuperellipseGeometry(const Point& center,
+                                           Scalar radius,
+                                           int degree,
+                                           Scalar alpha,
+                                           Scalar beta)
+    : center_(center),
+      degree_(degree),
+      radius_(radius),
+      alpha_(alpha),
+      beta_(beta) {}
+
+GeometryResult SuperellipseGeometry::GetPositionBuffer(
     const ContentContext& renderer,
     const Entity& entity,
     RenderPass& pass) const {
   // https://math.stackexchange.com/questions/2573746/superellipse-parametric-equation
   Scalar a = alpha_;
   Scalar b = beta_;
-  Scalar n = 4;
+  Scalar n = degree_;
 
   // TODO(jonahwilliams): determine parameter values based on scaling factor.
   Scalar step = kPi / 80;
@@ -41,15 +45,30 @@ GeometryResult RectellipseGeometry::GetPositionBuffer(
   Scalar y = b * pow(abs(sin(kPi / 2)), 2 / n);
   points.emplace_back(x, y);
 
-  // Reflect into the other 3 quadrants and generate the tessellated mesh.
   std::vector<Point> geometry;
   static constexpr Point reflection[4] = {{1, 1}, {-1, 1}, {-1, -1}, {1, -1}};
 
+  if (points.empty()) {
+    return {};
+  }
+
+  // Reflect into the 4 quadrants and generate the tessellated mesh. The
+  // iteration order is reversed so that the trianges are continuous from
+  // quadrant to quadrant.
   geometry.push_back(center_);
-  for (auto sc : reflection) {
-    for (auto pt : points) {
-      geometry.push_back(center_ + ((sc * pt) * radius_));
-    }
+  for (auto i = 0u; i < points.size(); i++) {
+    geometry.push_back(center_ + ((reflection[0] * points[i]) * radius_));
+  }
+  for (auto i = 0u; i < points.size(); i++) {
+    geometry.push_back(
+        center_ + ((reflection[1] * points[points.size() - i - 1]) * radius_));
+  }
+  for (auto i = 0u; i < points.size(); i++) {
+    geometry.push_back(center_ + ((reflection[2] * points[i]) * radius_));
+  }
+  for (auto i = 0u; i < points.size(); i++) {
+    geometry.push_back(
+        center_ + ((reflection[3] * points[points.size() - i - 1]) * radius_));
   }
 
   std::vector<uint16_t> indices;
@@ -77,17 +96,18 @@ GeometryResult RectellipseGeometry::GetPositionBuffer(
   };
 }
 
-std::optional<Rect> RectellipseGeometry::GetCoverage(
+std::optional<Rect> SuperellipseGeometry::GetCoverage(
     const Matrix& transform) const {
-  return Rect::MakeMaximum();
+  return Rect::MakeOriginSize(center_ - Point(radius_, radius_),
+                              Size(radius_ * 2, radius_ * 2));
 }
 
-bool RectellipseGeometry::CoversArea(const Matrix& transform,
-                                     const Rect& rect) const {
+bool SuperellipseGeometry::CoversArea(const Matrix& transform,
+                                      const Rect& rect) const {
   return false;
 }
 
-bool RectellipseGeometry::IsAxisAlignedRect() const {
+bool SuperellipseGeometry::IsAxisAlignedRect() const {
   return false;
 }
 
diff --git a/impeller/entity/geometry/rectellipse_geometry.h b/impeller/entity/geometry/superellipse_geometry.h
similarity index 51%
rename from impeller/entity/geometry/rectellipse_geometry.h
rename to impeller/entity/geometry/superellipse_geometry.h
index dc862f1d9eb0d..a0d8eb4a355e0 100644
--- a/impeller/entity/geometry/rectellipse_geometry.h
+++ b/impeller/entity/geometry/superellipse_geometry.h
@@ -2,22 +2,23 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef FLUTTER_IMPELLER_ENTITY_GEOMETRY_RECTELLIPSE_GEOMETRY_H_
-#define FLUTTER_IMPELLER_ENTITY_GEOMETRY_RECTELLIPSE_GEOMETRY_H_
+#ifndef FLUTTER_IMPELLER_ENTITY_GEOMETRY_SUPERELLIPSE_GEOMETRY_H_
+#define FLUTTER_IMPELLER_ENTITY_GEOMETRY_SUPERELLIPSE_GEOMETRY_H_
 
 #include "impeller/entity/geometry/geometry.h"
 
 namespace impeller {
 
-// Geometry class that can generate vertices for a rectellipse.
-class RectellipseGeometry final : public Geometry {
+// Geometry class that can generate vertices for a super ellipse.
+class SuperellipseGeometry final : public Geometry {
  public:
-  explicit RectellipseGeometry(const Point& center,
-                               Scalar radius,
-                               Scalar alpha,
-                               Scalar beta);
+  explicit SuperellipseGeometry(const Point& center,
+                                Scalar radius,
+                                int degree,
+                                Scalar alpha,
+                                Scalar beta);
 
-  ~RectellipseGeometry() = default;
+  ~SuperellipseGeometry() = default;
 
   // |Geometry|
   bool CoversArea(const Matrix& transform, const Rect& rect) const override;
@@ -35,15 +36,17 @@ class RectellipseGeometry final : public Geometry {
   std::optional<Rect> GetCoverage(const Matrix& transform) const override;
 
   Point center_;
+  // 4 is a rectellipse
+  int degree_;
   Scalar radius_;
   Scalar alpha_;
   Scalar beta_;
 
-  RectellipseGeometry(const RectellipseGeometry&) = delete;
+  SuperellipseGeometry(const SuperellipseGeometry&) = delete;
 
-  RectellipseGeometry& operator=(const RectellipseGeometry&) = delete;
+  SuperellipseGeometry& operator=(const SuperellipseGeometry&) = delete;
 };
 
 }  // namespace impeller
 
-#endif  // FLUTTER_IMPELLER_ENTITY_GEOMETRY_RECTELLIPSE_GEOMETRY_H_
+#endif  // FLUTTER_IMPELLER_ENTITY_GEOMETRY_SUPERELLIPSE_GEOMETRY_H_

From 190dfc8acb3c93cd44e3cf2ef55ee975fa2ce532 Mon Sep 17 00:00:00 2001
From: jonahwilliams <jonahwilliams@google.com>
Date: Wed, 14 Aug 2024 17:55:59 -0700
Subject: [PATCH 03/10] linting.

---
 ci/licenses_golden/licenses_flutter               |  4 ++++
 impeller/entity/geometry/superellipse_geometry.cc | 15 ++++++---------
 2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/ci/licenses_golden/licenses_flutter b/ci/licenses_golden/licenses_flutter
index b650e4d16999a..2ec9a5af87ed5 100644
--- a/ci/licenses_golden/licenses_flutter
+++ b/ci/licenses_golden/licenses_flutter
@@ -42862,6 +42862,8 @@ ORIGIN: ../../../flutter/impeller/entity/geometry/round_rect_geometry.cc + ../..
 ORIGIN: ../../../flutter/impeller/entity/geometry/round_rect_geometry.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/entity/geometry/stroke_path_geometry.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/entity/geometry/stroke_path_geometry.h + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/entity/geometry/superellipse_geometry.cc + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/impeller/entity/geometry/superellipse_geometry.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/entity/geometry/vertices_geometry.cc + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/entity/geometry/vertices_geometry.h + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/impeller/entity/inline_pass_context.cc + ../../../flutter/LICENSE
@@ -45739,6 +45741,8 @@ FILE: ../../../flutter/impeller/entity/geometry/round_rect_geometry.cc
 FILE: ../../../flutter/impeller/entity/geometry/round_rect_geometry.h
 FILE: ../../../flutter/impeller/entity/geometry/stroke_path_geometry.cc
 FILE: ../../../flutter/impeller/entity/geometry/stroke_path_geometry.h
+FILE: ../../../flutter/impeller/entity/geometry/superellipse_geometry.cc
+FILE: ../../../flutter/impeller/entity/geometry/superellipse_geometry.h
 FILE: ../../../flutter/impeller/entity/geometry/vertices_geometry.cc
 FILE: ../../../flutter/impeller/entity/geometry/vertices_geometry.h
 FILE: ../../../flutter/impeller/entity/inline_pass_context.cc
diff --git a/impeller/entity/geometry/superellipse_geometry.cc b/impeller/entity/geometry/superellipse_geometry.cc
index 14418fe7f49f5..924c989027d5d 100644
--- a/impeller/entity/geometry/superellipse_geometry.cc
+++ b/impeller/entity/geometry/superellipse_geometry.cc
@@ -36,25 +36,21 @@ GeometryResult SuperellipseGeometry::GetPositionBuffer(
   // Generate the points for the top left quadrant, and then mirror to the other
   // quadrants.
   std::vector<Point> points;
-  for (Scalar t = 0; t < (kPi / 2) - step; t += step) {
+  points.reserve(40);
+  for (int i = 0; i < 40; i++) {
+    Scalar t = i * step;
     Scalar x = a * pow(abs(cos(t)), 2 / n);
     Scalar y = b * pow(abs(sin(t)), 2 / n);
     points.emplace_back(x, y);
   }
-  Scalar x = a * pow(abs(cos(kPi / 2)), 2 / n);
-  Scalar y = b * pow(abs(sin(kPi / 2)), 2 / n);
-  points.emplace_back(x, y);
 
-  std::vector<Point> geometry;
   static constexpr Point reflection[4] = {{1, 1}, {-1, 1}, {-1, -1}, {1, -1}};
 
-  if (points.empty()) {
-    return {};
-  }
-
   // Reflect into the 4 quadrants and generate the tessellated mesh. The
   // iteration order is reversed so that the trianges are continuous from
   // quadrant to quadrant.
+  std::vector<Point> geometry;
+  geometry.reserve(1 + 4 * points.size());
   geometry.push_back(center_);
   for (auto i = 0u; i < points.size(); i++) {
     geometry.push_back(center_ + ((reflection[0] * points[i]) * radius_));
@@ -72,6 +68,7 @@ GeometryResult SuperellipseGeometry::GetPositionBuffer(
   }
 
   std::vector<uint16_t> indices;
+  indices.reserve(geometry.size() * 3);
   for (auto i = 2u; i < geometry.size(); i++) {
     indices.push_back(0);
     indices.push_back(i - 1);

From ded4ae8ee4af492377b7b619868edd65170b5b8e Mon Sep 17 00:00:00 2001
From: jonahwilliams <jonahwilliams@google.com>
Date: Wed, 14 Aug 2024 17:59:11 -0700
Subject: [PATCH 04/10] quick fix

---
 impeller/entity/geometry/superellipse_geometry.cc | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/impeller/entity/geometry/superellipse_geometry.cc b/impeller/entity/geometry/superellipse_geometry.cc
index 924c989027d5d..709d0489dc22c 100644
--- a/impeller/entity/geometry/superellipse_geometry.cc
+++ b/impeller/entity/geometry/superellipse_geometry.cc
@@ -36,8 +36,8 @@ GeometryResult SuperellipseGeometry::GetPositionBuffer(
   // Generate the points for the top left quadrant, and then mirror to the other
   // quadrants.
   std::vector<Point> points;
-  points.reserve(40);
-  for (int i = 0; i < 40; i++) {
+  points.reserve(41);
+  for (int i = 0; i < 41; i++) {
     Scalar t = i * step;
     Scalar x = a * pow(abs(cos(t)), 2 / n);
     Scalar y = b * pow(abs(sin(t)), 2 / n);

From 0d161ad26f3d1702404e6874aab3203485162bbe Mon Sep 17 00:00:00 2001
From: jonahwilliams <jonahwilliams@google.com>
Date: Wed, 14 Aug 2024 20:39:46 -0700
Subject: [PATCH 05/10] move to entity tests.

---
 impeller/aiks/aiks_unittests.cc     | 33 -----------------------------
 impeller/aiks/canvas.cc             | 16 --------------
 impeller/aiks/canvas.h              |  7 ------
 impeller/entity/entity_unittests.cc | 32 ++++++++++++++++++++++++++++
 4 files changed, 32 insertions(+), 56 deletions(-)

diff --git a/impeller/aiks/aiks_unittests.cc b/impeller/aiks/aiks_unittests.cc
index e84b3cf37e71c..cc36718db17bd 100644
--- a/impeller/aiks/aiks_unittests.cc
+++ b/impeller/aiks/aiks_unittests.cc
@@ -486,39 +486,6 @@ TEST_P(AiksTest, CorrectClipDepthAssignedToEntities) {
   }
 }
 
-TEST_P(AiksTest, DrawSuperEllipse) {
-  auto callback = [&](AiksContext& renderer) -> std::optional<Picture> {
-    // UI state.
-    static float alpha = 10;
-    static float beta = 10;
-    static float radius = 40;
-    static int degree = 4;
-    static Color color = Color::Red();
-
-    if (AiksTest::ImGuiBegin("Controls", nullptr,
-                             ImGuiWindowFlags_AlwaysAutoResize)) {
-      ImGui::SliderFloat("Alpha", &alpha, 0, 100);
-      ImGui::SliderFloat("Beta", &beta, 0, 100);
-      ImGui::SliderInt("Degreee", &degree, 1, 20);
-      ImGui::SliderFloat("Radius", &radius, 0, 400);
-      ImGui::ColorEdit4("Color", reinterpret_cast<float*>(&color));
-      ImGui::End();
-    }
-
-    Canvas canvas;
-    canvas.DrawSuperellipse(
-        /*center=*/{400, 400},
-        /*radius=*/radius,
-        /*degree=*/degree,
-        /*alpha=*/alpha,
-        /*beta=*/beta,
-        /*paint=*/{.color = color});
-    return canvas.EndRecordingAsPicture();
-  };
-
-  OpenPlaygroundHere(callback);
-}
-
 }  // namespace testing
 }  // namespace impeller
 
diff --git a/impeller/aiks/canvas.cc b/impeller/aiks/canvas.cc
index c8860043bf972..2a69722f49610 100644
--- a/impeller/aiks/canvas.cc
+++ b/impeller/aiks/canvas.cc
@@ -847,22 +847,6 @@ void Canvas::SaveLayer(const Paint& paint,
   new_layer_pass.SetDelegate(std::make_shared<PaintPassDelegate>(paint_copy));
 }
 
-void Canvas::DrawSuperellipse(Point center,
-                              Scalar radius,
-                              int degree,
-                              Scalar alpha,
-                              Scalar beta,
-                              const Paint& paint) {
-  Entity entity;
-  entity.SetTransform(GetCurrentTransform());
-  entity.SetBlendMode(paint.blend_mode);
-  entity.SetContents(CreateContentsForGeometryWithFilters(
-      paint, std::make_shared<SuperellipseGeometry>(center, radius, degree,
-                                                    alpha, beta)));
-
-  AddRenderEntityToCurrentPass(std::move(entity));
-}
-
 void Canvas::DrawTextFrame(const std::shared_ptr<TextFrame>& text_frame,
                            Point position,
                            const Paint& paint) {
diff --git a/impeller/aiks/canvas.h b/impeller/aiks/canvas.h
index 11ee307247e1e..e5bdc379b0622 100644
--- a/impeller/aiks/canvas.h
+++ b/impeller/aiks/canvas.h
@@ -133,13 +133,6 @@ class Canvas {
                  const Paint& paint,
                  SamplerDescriptor sampler = {});
 
-  void DrawSuperellipse(Point center,
-                        Scalar radius,
-                        int degree,
-                        Scalar alpha,
-                        Scalar beta,
-                        const Paint& paint);
-
   void DrawImageRect(
       const std::shared_ptr<Image>& image,
       Rect source,
diff --git a/impeller/entity/entity_unittests.cc b/impeller/entity/entity_unittests.cc
index 7f476eb5281d6..92408fd7da6e2 100644
--- a/impeller/entity/entity_unittests.cc
+++ b/impeller/entity/entity_unittests.cc
@@ -39,6 +39,7 @@
 #include "impeller/entity/geometry/geometry.h"
 #include "impeller/entity/geometry/point_field_geometry.h"
 #include "impeller/entity/geometry/stroke_path_geometry.h"
+#include "impeller/entity/geometry/superellipse_geometry.h"
 #include "impeller/entity/render_target_cache.h"
 #include "impeller/geometry/color.h"
 #include "impeller/geometry/geometry_asserts.h"
@@ -2587,6 +2588,37 @@ TEST_P(EntityTest, CanRenderEmptyPathsWithoutCrashing) {
   ASSERT_TRUE(OpenPlaygroundHere(std::move(entity)));
 }
 
+TEST_P(EntityTest, DrawSuperEllipse) {
+  auto callback = [&](ContentContext& context, RenderPass& pass) -> bool {
+    // UI state.
+    static float alpha = 10;
+    static float beta = 10;
+    static float radius = 40;
+    static int degree = 4;
+    static Color color = Color::Red();
+
+    ImGui::Begin("Controls", nullptr, ImGuiWindowFlags_AlwaysAutoResize);
+    ImGui::SliderFloat("Alpha", &alpha, 0, 100);
+    ImGui::SliderFloat("Beta", &beta, 0, 100);
+    ImGui::SliderInt("Degreee", &degree, 1, 20);
+    ImGui::SliderFloat("Radius", &radius, 0, 400);
+    ImGui::ColorEdit4("Color", reinterpret_cast<float*>(&color));
+    ImGui::End();
+
+    auto contents = std::make_shared<SolidColorContents>();
+    contents->SetColor(color);
+    contents->SetGeometry(std::make_shared<SuperellipseGeometry>(
+        Point{400, 400}, radius, degree, alpha, beta));
+
+    Entity entity;
+    entity.SetContents(contents);
+
+    return entity.Render(context, pass);
+  };
+
+  ASSERT_TRUE(OpenPlaygroundHere(callback));
+}
+
 }  // namespace testing
 }  // namespace impeller
 

From e3693280695b506c47eddac555960b9fe35d271f Mon Sep 17 00:00:00 2001
From: jonahwilliams <jonahwilliams@google.com>
Date: Wed, 14 Aug 2024 20:46:46 -0700
Subject: [PATCH 06/10] add doc comment.

---
 impeller/entity/geometry/superellipse_geometry.h | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/impeller/entity/geometry/superellipse_geometry.h b/impeller/entity/geometry/superellipse_geometry.h
index a0d8eb4a355e0..3020af328c0da 100644
--- a/impeller/entity/geometry/superellipse_geometry.h
+++ b/impeller/entity/geometry/superellipse_geometry.h
@@ -9,7 +9,17 @@
 
 namespace impeller {
 
-// Geometry class that can generate vertices for a super ellipse.
+/// Geometry class that can generate vertices for a superellipse.
+///
+/// A Superellipse is an ellipse-like shape that is defined by the parameters N,
+/// alpha, and beta:
+///
+///  1 = |x / b| ^n + |y / a| ^n
+///
+/// The radius and center apply a uniform scaling and offset that is separate
+/// from alpha or beta. When n = 4, the shape is referred to as a rectellipse.
+///
+/// See also: https://en.wikipedia.org/wiki/Superellipse
 class SuperellipseGeometry final : public Geometry {
  public:
   explicit SuperellipseGeometry(const Point& center,

From 2e9d74b57f2051fafa458a03ef036aa2af111469 Mon Sep 17 00:00:00 2001
From: Jonah Williams <jonahwilliams@google.com>
Date: Thu, 15 Aug 2024 11:18:51 -0700
Subject: [PATCH 07/10] Update superellipse_geometry.h

---
 impeller/entity/geometry/superellipse_geometry.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/impeller/entity/geometry/superellipse_geometry.h b/impeller/entity/geometry/superellipse_geometry.h
index 3020af328c0da..19c049f2962ff 100644
--- a/impeller/entity/geometry/superellipse_geometry.h
+++ b/impeller/entity/geometry/superellipse_geometry.h
@@ -24,7 +24,7 @@ class SuperellipseGeometry final : public Geometry {
  public:
   explicit SuperellipseGeometry(const Point& center,
                                 Scalar radius,
-                                int degree,
+                                Scalar degree,
                                 Scalar alpha,
                                 Scalar beta);
 
@@ -47,7 +47,7 @@ class SuperellipseGeometry final : public Geometry {
 
   Point center_;
   // 4 is a rectellipse
-  int degree_;
+  Scalar degree_;
   Scalar radius_;
   Scalar alpha_;
   Scalar beta_;

From 4cc92e0f2d07c9b05cf17177dca469bf4e840ebd Mon Sep 17 00:00:00 2001
From: Jonah Williams <jonahwilliams@google.com>
Date: Thu, 15 Aug 2024 11:19:03 -0700
Subject: [PATCH 08/10] Update superellipse_geometry.cc

---
 impeller/entity/geometry/superellipse_geometry.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/impeller/entity/geometry/superellipse_geometry.cc b/impeller/entity/geometry/superellipse_geometry.cc
index 709d0489dc22c..44d64c347c4b4 100644
--- a/impeller/entity/geometry/superellipse_geometry.cc
+++ b/impeller/entity/geometry/superellipse_geometry.cc
@@ -12,7 +12,7 @@ namespace impeller {
 
 SuperellipseGeometry::SuperellipseGeometry(const Point& center,
                                            Scalar radius,
-                                           int degree,
+                                           Scalar degree,
                                            Scalar alpha,
                                            Scalar beta)
     : center_(center),

From a037a7d4c384cb13914796a1f039f2142d7cdb75 Mon Sep 17 00:00:00 2001
From: Jonah Williams <jonahwilliams@google.com>
Date: Thu, 15 Aug 2024 11:31:17 -0700
Subject: [PATCH 09/10] Update superellipse_geometry.cc

---
 impeller/entity/geometry/superellipse_geometry.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/impeller/entity/geometry/superellipse_geometry.cc b/impeller/entity/geometry/superellipse_geometry.cc
index 44d64c347c4b4..e22b6c2d502a2 100644
--- a/impeller/entity/geometry/superellipse_geometry.cc
+++ b/impeller/entity/geometry/superellipse_geometry.cc
@@ -37,7 +37,7 @@ GeometryResult SuperellipseGeometry::GetPositionBuffer(
   // quadrants.
   std::vector<Point> points;
   points.reserve(41);
-  for (int i = 0; i < 41; i++) {
+  for (int i = 0; i <= 40; i++) {
     Scalar t = i * step;
     Scalar x = a * pow(abs(cos(t)), 2 / n);
     Scalar y = b * pow(abs(sin(t)), 2 / n);

From e014ce9e511e3f2a82684a268c43ebf16e64256b Mon Sep 17 00:00:00 2001
From: jonahwilliams <jonahwilliams@google.com>
Date: Thu, 15 Aug 2024 14:36:03 -0700
Subject: [PATCH 10/10] inline radius.

---
 impeller/entity/geometry/superellipse_geometry.cc | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/impeller/entity/geometry/superellipse_geometry.cc b/impeller/entity/geometry/superellipse_geometry.cc
index 709d0489dc22c..1181d809b8d0f 100644
--- a/impeller/entity/geometry/superellipse_geometry.cc
+++ b/impeller/entity/geometry/superellipse_geometry.cc
@@ -41,7 +41,7 @@ GeometryResult SuperellipseGeometry::GetPositionBuffer(
     Scalar t = i * step;
     Scalar x = a * pow(abs(cos(t)), 2 / n);
     Scalar y = b * pow(abs(sin(t)), 2 / n);
-    points.emplace_back(x, y);
+    points.emplace_back(x * radius_, y * radius_);
   }
 
   static constexpr Point reflection[4] = {{1, 1}, {-1, 1}, {-1, -1}, {1, -1}};
@@ -53,18 +53,18 @@ GeometryResult SuperellipseGeometry::GetPositionBuffer(
   geometry.reserve(1 + 4 * points.size());
   geometry.push_back(center_);
   for (auto i = 0u; i < points.size(); i++) {
-    geometry.push_back(center_ + ((reflection[0] * points[i]) * radius_));
+    geometry.push_back(center_ + (reflection[0] * points[i]));
   }
   for (auto i = 0u; i < points.size(); i++) {
-    geometry.push_back(
-        center_ + ((reflection[1] * points[points.size() - i - 1]) * radius_));
+    geometry.push_back(center_ +
+                       (reflection[1] * points[points.size() - i - 1]));
   }
   for (auto i = 0u; i < points.size(); i++) {
-    geometry.push_back(center_ + ((reflection[2] * points[i]) * radius_));
+    geometry.push_back(center_ + (reflection[2] * points[i]));
   }
   for (auto i = 0u; i < points.size(); i++) {
-    geometry.push_back(
-        center_ + ((reflection[3] * points[points.size() - i - 1]) * radius_));
+    geometry.push_back(center_ +
+                       (reflection[3] * points[points.size() - i - 1]));
   }
 
   std::vector<uint16_t> indices;