RaycastHit.triangleIndex 三角形索引

// Attach this script to a camera and it will
// draw a debug line triangle triangle
// at the triangle where you place the mouse.
//附加这个脚本到相机然后它将绘制一个调试直线三角形，在放置鼠标的三角形上
function Update () {
	// Only if we hit something, do we continue
	//如果碰到了什么东西，继续
	var hit : RaycastHit;
	if (!Physics.Raycast (camera.ScreenPointToRay(Input.mousePosition), hit))
		return;

	// Just in case, also make sure the collider also has a renderer
	// material and texture
	//以防万一，确保碰撞器也有一个渲染器、材质和纹理
	var meshCollider = hit.collider as MeshCollider;
	if (meshCollider == null || meshCollider.sharedMesh == null)
		return;

	var mesh : Mesh = meshCollider.sharedMesh;
	var vertices = mesh.vertices;
	var triangles = mesh.triangles;

	// Extract local space vertices that were hit
	//取回碰到的本地坐标点
	var p0 = vertices[triangles[hit.triangleIndex * 3 + 0]];
	var p1 = vertices[triangles[hit.triangleIndex * 3 + 1]];
	var p2 = vertices[triangles[hit.triangleIndex * 3 + 2]];

	// Transform local space vertices to world space
	//变换本地空间点到世界空间
	var hitTransform : Transform = hit.collider.transform;
	p0 = hitTransform.TransformPoint(p0);
	p1 = hitTransform.TransformPoint(p1);
	p2 = hitTransform.TransformPoint(p2);

	// Display with Debug.DrawLine
	//显示调试线
	Debug.DrawLine(p0, p1);
	Debug.DrawLine(p1, p2);
	Debug.DrawLine(p2, p0);
}