PolygonColliderの多すぎる頂点を減らす。ベースはEngidia SCP - Eduard Bosch ([email protected])さんのRemoveInternalShapes

ReduceVertexPolygonCollider2D.cs

/**
 * Author: Engidia SCP - Eduard Bosch ([email protected])
 * File: RemoveInternalShapes.cs
 */
using UnityEngine;
using UnityEditor;
using System.Collections;
using System.Collections.Generic;
using System.Linq;

public class ReduceVertexPolygonCollider2D
{
	[MenuItem ("GameObject/Reduce Vertex of PolygonCollider", true)]
	static bool ValidateRemoveShapes ()
	{
		foreach (GameObject objects in Selection.gameObjects) {
			PolygonCollider2D collider = objects.GetComponent<PolygonCollider2D> ();
			return (collider != null && collider.pathCount >= 1);
		}
		return false;
	}
	
	[MenuItem ("GameObject/Reduce Vertex of PolygonCollider")]
	static void RemoveShapes ()
	{
		foreach (GameObject objects in Selection.gameObjects) {
			PolygonCollider2D collider = objects.GetComponent<PolygonCollider2D> ();
			if (collider == null) {
				continue;
			}
			
			Undo.RecordObject (collider, "Remove Interior Shapes");
			
			var path1 = GetOutlinePath (collider);
			var path2 = RemovePlane (path1);
			var path3 = RemoveClosePolygon (path2);

			collider.SetPath (0, path3);
		}
	}

	static Vector2[] GetOutlinePath (PolygonCollider2D collider)
	{
		int lExteriorShape = 0;
		float lLeftmostPoint = Mathf.Infinity;
		
		for (int i=0, length=collider.pathCount; i<length; ++i) {
			Vector2[] lPath = collider.GetPath (i);
			
			foreach (Vector2 lPoint in lPath) {
				if (lPoint.x < lLeftmostPoint) {
					lExteriorShape = i;
					lLeftmostPoint = lPoint.x;
				}
			}
		}

		collider.pathCount = 1;

		return collider.GetPath (lExteriorShape);
	}

	static Vector2 [] RemoveClosePolygon (Vector2[] lPath)
	{
		List<Vector2> verticesList = new List<Vector2> (lPath);
		
		
		foreach (var node in lPath) {
			
			if (verticesList.Exists (item => Vector3.Distance (node, item) < 0.3f && item != node)) {
				verticesList.Remove (node);
				continue;
			}
		}

		return verticesList.ToArray ();
	}

	static Vector2[] RemovePlane (Vector2[] lPath)
	{
		var verticesList = new List<Vector2> (lPath);
		for (int i=1; i<lPath.Length - 1; i+= 2) {
			var first = lPath [i - 1];
			var second = lPath [i];
			var third = lPath [i + 1];
			
			var angle1 = Vector2.Angle (first, second);
			var angle2 = Vector2.Angle (second, third);
			
			if (Mathf.Abs (angle1 - angle2) < 30) {
				verticesList.Remove (second);
				continue;
			}
		}
		return verticesList.ToArray ();
	}
}

PolygonCollider2Dがアタッチされているオブジェクト選択中にGameObject>Reduce Vertex of PolygonColliderでポリゴンが削減される。
何度も実行するとポリゴンがより削減されて21verticesとかになる場合がある。その場合当然荒くなる。