From 7f93d95f6bc680fa804f7f973c3248d08708875a Mon Sep 17 00:00:00 2001
From: Syntriax <Syntriax@gmail.com>
Date: Sat, 5 Apr 2025 14:56:06 +0300
Subject: [PATCH] feat: Shape2D convex triangulation methods added

---
 Engine.Core/Primitives/Shape2D.cs | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/Engine.Core/Primitives/Shape2D.cs b/Engine.Core/Primitives/Shape2D.cs
index 59c894c..19866c7 100644
--- a/Engine.Core/Primitives/Shape2D.cs
+++ b/Engine.Core/Primitives/Shape2D.cs
@@ -99,6 +99,31 @@ public readonly struct Shape2D(List<Vector2D> vertices) : IEnumerable<Vector2D>
         return new Triangle(p1, p2, p3);
     }
 
+    /// <summary>
+    /// Triangulates the given convex shape.
+    /// </summary>
+    /// <param name="shape">The shape to triangulate.</param>
+    /// <param name="triangles">The list to populate with triangles.</param>
+    public static void TriangulateConvex(Shape2D shape, IList<Triangle> triangles)
+    {
+        triangles.Clear();
+
+        for (int i = 2; i < shape.Vertices.Count; i++)
+            triangles.Add(new Triangle(shape[0], shape[i - 1], shape[i]));
+    }
+
+    /// <summary>
+    /// Triangulates the given convex shape.
+    /// </summary>
+    /// <param name="shape">The shape to triangulate.</param>
+    /// <returns>A list of <see cref="Triangle"/>s that makes up the given convex <see cref="Shape2D"/>.</returns>
+    public static List<Triangle> TriangulateConvex(Shape2D shape)
+    {
+        List<Triangle> triangles = new(shape.Vertices.Count - 2);
+        TriangulateConvex(shape, triangles);
+        return triangles;
+    }
+
     /// <summary>
     /// Gets the lines that form the edges of the shape.
     /// </summary>
@@ -229,6 +254,12 @@ public static class Shape2DExtensions
     /// <inheritdoc cref="Shape2D.GetSuperTriangle(Shape2D)" />
     public static Triangle ToSuperTriangle(this Shape2D shape) => Shape2D.GetSuperTriangle(shape);
 
+    /// <inheritdoc cref="Shape2D.TriangulateConvex(Shape2D, IList{Triangle})" />
+    public static void ToTrianglesConvex(this Shape2D shape, IList<Triangle> lines) => Shape2D.TriangulateConvex(shape, lines);
+
+    /// <inheritdoc cref="Shape2D.TriangulateConvex(Shape2D)" />
+    public static List<Triangle> ToTrianglesConvex(this Shape2D shape) => Shape2D.TriangulateConvex(shape);
+
     /// <inheritdoc cref="Shape2D.GetLines(Shape2D, IList{Line2D})" />
     public static void ToLines(this Shape2D shape, IList<Line2D> lines) => Shape2D.GetLines(shape, lines);