Unity 代码点击抠图

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class Test : MonoBehaviour {
public float allowance;
public Texture2D wallTexture;
private Texture2D tempTexture;
private float wall_height; // 【获图片宽高信息】
private float wall_width;
RaycastHit hitInfo;

void Start () {

    wallTexture = GetComponent<MeshRenderer>().material.mainTexture as Texture2D;
    wall_height = wallTexture.height;
    wall_width = wallTexture.width;
    tempTexture = Instantiate(wallTexture) as Texture2D;
    GetComponent<MeshRenderer>().material.mainTexture = tempTexture;

}


void Update () {
    if (Input.GetMouseButtonDown(0))
    {
        Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
        if (Physics.Raycast(ray,out hitInfo))
        {
            //获取鼠标点击到的像素的颜色
            Vector2 uv = hitInfo.textureCoord;
            Color color = wallTexture.GetPixel((int)(uv.x*wall_width),(int)( uv.y*wall_height));
            //遍历图像所有像素点
            for (int i = 0; i < wall_width; i++)
            {
                for (int j = 0; j < wall_height; j++)
                {
                    Color tcolor = wallTexture.GetPixel(i, j);
                    //计算容差
                    float r = color.r - tcolor.r;
                    float g = color.g - tcolor.g;
                    float b = color.b - tcolor.b;
                    float diff = Mathf.Sqrt(r * r + g * g + b * b)*255;
              
                    if (diff< allowance)
                    {
                        //改成透明  
                        tempTexture.SetPixel(i, j, new Color(0, 0, 0, 0));
                    }
                }
            }

            tempTexture.Apply();
        }
    }
}

}