All intersection point in single collider

I want to get all intersection point in single collider. I used Collider.Raycast, but this method only give one point (entry point).

I used reversed raycasting to find exit point. But, this method's have problem in some mesh collider.


In photo, i successfully get red points (entry and exit points). But, i need all intersection point.
I think Collider.RaycastAll method is good for this problem. But Unity hasn't RaycastAll method for single collider.

 

RaycastAll only give one point only per single collider. In here, I used reversed raycasting for finding exit point.

 

I need the same thing.
But your link does not work.
would you please upload it again?

 

Thank you very much.
your example is very helpful.
if I want to use the method with Circle collider which part should be changed?

 

Thank you so muchfor your hard work.
I use it a lot.
I also have a trouble using ray 2d.
I designed a ray reflection.
but it work incorrectly at some angle of the ray source
here is my Q on stackoverflow:
https://stackoverflow.com/questions/64400118/why-the-ray-reflection-system-not-work-correctly

 

Thanks a lot for this amazing script. Works like a charm in
However It was only giving me points of the first element of the polygon collider. I modified it a little like this now it covers entire sprite with polygon islands

Code (CSharp):

1.  
2. using System.Collections;
3. using System.Collections.Generic;
4. using UnityEngine;
5.  
6. public class ClippingScript : MonoBehaviour
7. {
8.     public Vector2 LineStart;
9.     public Vector2 LineEnd;
10.     public float crossScale = 0.05f;
11.  
12.     Vector2[] polygonPoints;
13.     PolygonCollider2D polygon;
14.     List<Vector2> clipPoints = new List<Vector2>();
15.  
16.  
17.     // Use this for initialization
18.     void Start()
19.     {
20.         polygon = GetComponent<PolygonCollider2D>();
21.     }
22.  
23.     // Update is called once per frame
24.     void Update()
25.     {
26.         // Fetch the polygon points in world-space (not the most efficient way of doing things)!
27.         List<Vector2> vecs = new List<Vector2>();
28.         for (int x = 0; x < polygon.pathCount; x++)
29.         {
30.             Vector2[] pax = polygon.GetPath(x);
31.             for (int y = 0; y < pax.Length; y++)
32.             {
33.                 vecs.Add(pax[y]);
34.             }
35.         }
36.         polygonPoints = vecs.ToArray();
37.         vecs.Clear();
38.         vecs.TrimExcess();
39.         vecs = null;
40.        
41.         for (var i = 0; i < polygonPoints.Length; ++i)
42.             polygonPoints[i] = transform.TransformPoint(polygonPoints[i]);
43.  
44.         // Perform clipping against the polygon.
45.         clipPoints.Clear();
46.         var pointCount = polygonPoints.Length;
47.         for (int i = 0, j = pointCount - 1; i < pointCount; j = i++)
48.         {
49.             var edgeStart = polygonPoints[i];
50.             var edgeEnd = polygonPoints[j];
51.  
52.             Vector2 clipPoint;
53.             if (LineSegmentIntersection(LineStart, LineEnd, edgeStart, edgeEnd, out clipPoint))
54.                 clipPoints.Add(clipPoint);
55.         }
56.  
57.         // Draw the clipping line.
58.         Debug.DrawLine(LineStart, LineEnd, Color.red);
59.  
60.         // Draw the clip points.
61.         foreach (var v in clipPoints)
62.         {
63.             var clipPoint = (Vector3)v;
64.             Debug.DrawLine(clipPoint + (Vector3.left * crossScale), clipPoint + (Vector3.right * crossScale), Color.white);
65.             Debug.DrawLine(clipPoint + (Vector3.up * crossScale), clipPoint + (Vector3.down * crossScale), Color.white);
66.         }
67.     }
68.  
69.     bool LineSegmentIntersection(Vector2 a, Vector2 b, Vector2 c, Vector2 d, out Vector2 point)
70.     {
71.         // Sign of areas correspond to which side of ab points c and d are.
72.         float area1 = SignedTriangleArea(a, b, d);
73.         float area2 = SignedTriangleArea(a, b, c);
74.  
75.         // If c and d are on different sides of ab, areas have different signs.
76.         if (area1 * area2 < 0.0f)
77.         {
78.             // Compute signs for a and b with respect to segment cd.
79.             float area3 = SignedTriangleArea(c, d, a);
80.             float area4 = area3 + area2 - area1;
81.  
82.             // Points a and b on different sides of cd if areas have different signs.
83.             if (area3 * area4 < 0.0f)
84.             {
85.                 float time = area3 / (area3 - area4);
86.                 point = a + time * (b - a);
87.                 return true;
88.             }
89.         }
90.  
91.         // Segments are not intersecting or collinear.
92.         point = Vector2.zero;
93.         return false;
94.     }
95.  
96.     float SignedTriangleArea(Vector2 a, Vector2 b, Vector2 c)
97.     {
98.         return (a.x - c.x) * (b.y - c.y) - (a.y - c.y) * (b.x - c.x);
99.     }
100.  
101. }

 

Code (CSharp):

1. // Fetch the polygon points in world-space (not the most efficient way of doing things)!
2.         polygonPoints = polygon.points;
3.         for (var i = 0; i < polygonPoints.Length; ++i)
4.             polygonPoints[i] = transform.TransformPoint (polygonPoints[i]);

I've been stuck at this for 3 days already, how can I find the intersection without finding global coordinates or find them in a more optimized way? My FPS drops very much because of this function, I checked it with a stopwatch. please help