Unity3d 制作动态Mesh且可以随地面凹凸起伏

适用情景：主角带着光环，光环用一张贴图，要贴在地面上，并且随地面凹凸起伏

//代码

using UnityEngine;

using System.Collections;

[RequireComponent(typeof(MeshFilter))]

[RequireComponent(typeof(MeshRenderer))]

public class test : MonoBehaviour {

	private MeshFilter mFilter;

	private Mesh mMesh;

	public int QuadNum = 1;

	public float QuadLength = 1;

	// Use this for initialization

	void Start () {

		mFilter = gameObject.GetComponent<MeshFilter>();

		mMesh = new Mesh();

		mFilter.sharedMesh = mMesh;

		mMesh.MarkDynamic();

		var quadNum = QuadNum * 2;

		var ptNum = quadNum + 1;

		var h_len = QuadNum * QuadLength;

		var len = h_len * 2;

		var vertices = new Vector3[ptNum * ptNum];

		var uv = new Vector2[ptNum * ptNum];

		var triangle = new int[QuadNum * 2 * QuadNum * 2 * 6];

		var offset = new Vector3(-h_len, 0, -h_len);

		for (int j = 0; j < ptNum; j++)

		{

			for (int i = 0; i < ptNum; i++)

			{

				int idx = j*ptNum+i;

				uv[idx] = new Vector2(i * 1.0f / ptNum, j * 1.0f / ptNum);

			}

		}

		int it = 0;

		for (int j = 0; j < quadNum; j++)

		{

			for (int i = 0; i < quadNum; i++)

			{

				int quadId = j * quadNum + i;

				int p0 = quadId + j;

				int p1 = p0 + ptNum;

				int p2 = p1 + 1;

				int p3 = p0 + 1;

				triangle[it++] = p0;

				triangle[it++] = p1;

				triangle[it++] = p2;

				triangle[it++] = p0;

				triangle[it++] = p2;

				triangle[it++] = p3;

			}

		}

		mMesh.vertices = vertices;

		mMesh.uv = uv;

		mMesh.triangles = triangle;

 		}

	// Update is called once per frame

	protected virtual void Update () {

		var quadNum = QuadNum * 2;

		var ptNum = quadNum + 1;

		var h_len = QuadNum * QuadLength;

		var len = h_len * 2;

		var vertices = new Vector3[ptNum * ptNum];

		var offset = new Vector3(-h_len, 0, -h_len);

		var ray = new Ray(Vector3.down, Vector3.down);

		var hit = new RaycastHit();

		for (int j = 0; j < ptNum; j++)

		{

			for (int i = 0; i < ptNum; i++)

			{

				int idx = j * ptNum + i;

				var pt = new Vector3(i * QuadLength, 0, j * QuadLength);

				ray.origin = transform.localToWorldMatrix.MultiplyPoint3x4(pt) + new Vector3(0, 10, 0);

				if (Physics.Raycast(ray, out hit, 100))

				{

					pt = transform.worldToLocalMatrix.MultiplyPoint3x4(hit.point);

				}

				vertices[i + j * ptNum] = pt;

			}

		}

		mMesh.vertices = vertices;

	}

}