Unity3d  用鼠标拾取模型的顶点

RaycastHit hit;
       Ray ray =Camera.mainCamera.ScreenPointToRay(Input.mousePosition);
       if (Physics.Raycast(ray, out hit, 100))
        {
           spheretransform.position = hit.point;

           //拾取三角面前提是物体含有一个MeshCollider碰撞器
           MeshCollider collider = hit.collider as MeshCollider;
           if (collider == null||collider.sharedMesh==null)
               return;

           //获取碰撞器所在物体的Mesh网格
           Mesh mesh0 = collider.sharedMesh;

           //获取Mesh网格的所有顶点
           Vector3[] vertices = mesh0.vertices;

            //获取mesh的三角形索引，这里的索引的就是模型顶点数组的下标
           int[] triangles = mesh0.triangles;

           //然后通过hit.triangleIndex(摄像碰撞到的三角形的第一个点的索引)

            //然后+1，+2，获取三角形另外两个点的坐标
           Vector3 p0 = vertices[triangles[hit.triangleIndex * 3]];
           Vector3 p1 = vertices[triangles[hit.triangleIndex * 3 + 1]];
           Vector3 p2 = vertices[triangles[hit.triangleIndex * 3 + 2]];
           Transform transform = collider.transform;

            //上面的三个顶点是Mesh的本地坐标，需要用模型的Transform进行转换到世界坐标
           p0 = transform.TransformPoint(p0);
           p1 = transform.TransformPoint(p1);
           p2 = transform.TransformPoint(p2);

           //然后设置三个小球的位置到这个三个点，方便调试，呵呵！
           GameObject.Find("Sphere1").transform.position = p0;
           GameObject.Find("Sphere2").transform.position = p1;
           GameObject.Find("Sphere3").transform.position = p2;
       }