Created
May 14, 2015 19:40
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PolygonCollider2d to Mesh
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| using UnityEngine; | |
| using System; | |
| using System.Collections.Generic; | |
| using System.Linq; | |
| using System.Text; | |
| [ExecuteInEditMode] | |
| [RequireComponent(typeof(PolygonCollider2D))] | |
| [RequireComponent(typeof(MeshFilter))] | |
| [RequireComponent(typeof(MeshRenderer))] | |
| public class ColliderToPolygon : MonoBehaviour | |
| { | |
| #if UNITY_EDITOR | |
| #region Nested Class | |
| class Triangulator | |
| { | |
| private List<Vector2> m_points = new List<Vector2>(); | |
| public Triangulator(Vector2[] points) | |
| { | |
| m_points = new List<Vector2>(points); | |
| } | |
| public int[] Triangulate() | |
| { | |
| List<int> indices = new List<int>(); | |
| int n = m_points.Count; | |
| if (n < 3) | |
| return indices.ToArray(); | |
| int[] V = new int[n]; | |
| if (Area() > 0) | |
| { | |
| for (int v = 0; v < n; v++) | |
| V[v] = v; | |
| } | |
| else | |
| { | |
| for (int v = 0; v < n; v++) | |
| V[v] = (n - 1) - v; | |
| } | |
| int nv = n; | |
| int count = 2 * nv; | |
| for (int m = 0, v = nv - 1; nv > 2; ) | |
| { | |
| if ((count--) <= 0) | |
| return indices.ToArray(); | |
| int u = v; | |
| if (nv <= u) | |
| u = 0; | |
| v = u + 1; | |
| if (nv <= v) | |
| v = 0; | |
| int w = v + 1; | |
| if (nv <= w) | |
| w = 0; | |
| if (Snip(u, v, w, nv, V)) | |
| { | |
| int a, b, c, s, t; | |
| a = V[u]; | |
| b = V[v]; | |
| c = V[w]; | |
| indices.Add(a); | |
| indices.Add(b); | |
| indices.Add(c); | |
| m++; | |
| for (s = v, t = v + 1; t < nv; s++, t++) | |
| V[s] = V[t]; | |
| nv--; | |
| count = 2 * nv; | |
| } | |
| } | |
| indices.Reverse(); | |
| return indices.ToArray(); | |
| } | |
| private float Area() | |
| { | |
| int n = m_points.Count; | |
| float A = 0.0f; | |
| for (int p = n - 1, q = 0; q < n; p = q++) | |
| { | |
| Vector2 pval = m_points[p]; | |
| Vector2 qval = m_points[q]; | |
| A += pval.x * qval.y - qval.x * pval.y; | |
| } | |
| return (A * 0.5f); | |
| } | |
| private bool Snip(int u, int v, int w, int n, int[] V) | |
| { | |
| int p; | |
| Vector2 A = m_points[V[u]]; | |
| Vector2 B = m_points[V[v]]; | |
| Vector2 C = m_points[V[w]]; | |
| if (Mathf.Epsilon > (((B.x - A.x) * (C.y - A.y)) - ((B.y - A.y) * (C.x - A.x)))) | |
| return false; | |
| for (p = 0; p < n; p++) | |
| { | |
| if ((p == u) || (p == v) || (p == w)) | |
| continue; | |
| Vector2 P = m_points[V[p]]; | |
| if (InsideTriangle(A, B, C, P)) | |
| return false; | |
| } | |
| return true; | |
| } | |
| private bool InsideTriangle(Vector2 A, Vector2 B, Vector2 C, Vector2 P) | |
| { | |
| float ax, ay, bx, by, cx, cy, apx, apy, bpx, bpy, cpx, cpy; | |
| float cCROSSap, bCROSScp, aCROSSbp; | |
| ax = C.x - B.x; ay = C.y - B.y; | |
| bx = A.x - C.x; by = A.y - C.y; | |
| cx = B.x - A.x; cy = B.y - A.y; | |
| apx = P.x - A.x; apy = P.y - A.y; | |
| bpx = P.x - B.x; bpy = P.y - B.y; | |
| cpx = P.x - C.x; cpy = P.y - C.y; | |
| aCROSSbp = ax * bpy - ay * bpx; | |
| cCROSSap = cx * apy - cy * apx; | |
| bCROSScp = bx * cpy - by * cpx; | |
| return ((aCROSSbp >= 0.0f) && (bCROSScp >= 0.0f) && (cCROSSap >= 0.0f)); | |
| } | |
| } | |
| #endregion | |
| private void OnDrawGizmosSelected() | |
| { | |
| // Create Vector2 vertices | |
| Vector2[] vertices2D = GetComponent<PolygonCollider2D>().points; | |
| // Use the triangulator to get indices for creating triangles | |
| Triangulator tr = new Triangulator(vertices2D); | |
| int[] indices = tr.Triangulate(); | |
| // Create the Vector3 vertices | |
| Vector3[] vertices = new Vector3[vertices2D.Length]; | |
| for (int i = 0; i < vertices.Length; i++) | |
| { | |
| vertices[i] = new Vector3(vertices2D[i].x, vertices2D[i].y, 0); | |
| } | |
| var meshFilter = GetComponent<MeshFilter>(); | |
| if(meshFilter.sharedMesh == null) | |
| { | |
| meshFilter.sharedMesh = new Mesh(); | |
| } | |
| else | |
| { | |
| meshFilter.sharedMesh.Clear(); | |
| } | |
| var mesh = meshFilter.sharedMesh; | |
| mesh.vertices = vertices; | |
| mesh.triangles = indices; | |
| mesh.RecalculateNormals(); | |
| mesh.RecalculateBounds(); | |
| } | |
| #endif | |
| } |
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