UGUI利用RawImage实现涂鸦效果

using UnityEngine;
using System.Collections;
using UnityEngine.UI;
using YMFrame;
using System;
using System.Collections.Generic;
using Random = UnityEngine.Random;

namespace YMFrame
{
public class Painting : MonoBehaviour
{
private RenderTexture texRender; //画布
public Material _mPaintMaterial = null; //给定的shader新建材质
public Texture brushTypeTexture; //画笔纹理，半透明
public Shader paintShader;

    private float brushScale = 0.5f;
    public Color brushColor = Color.white; //new Color(219, 174, 68, 255) / 255;
    public RawImage raw_paint;                   //使用UGUI的RawImage显示，方便进行添加UI
    public RawImage totalShowRaw;
    private float lastDistance;
    private Vector3[] PositionArray = new Vector3[3];
    private int a = 0;
    private Vector3[] PositionArray1 = new Vector3[4];
    private int b = 0;
    private float[] speedArray = new float[4];
    private int s = 0;
    public int num = 50;

    public bool isPaintMagic;
    private int paintTimes;

    private float paint_x;

    private float raw_height;
    private float raw_width;

    private float raw_max_y;

    private float scale_x;
    private float scale_y;

    Vector3 startPosition = Vector3.zero;
    Vector3 endPosition = Vector3.zero;

    private Vector2 canvasSizeDelta;

    public void Init(RawImage _raw, Texture _brushType, RawImage _totalShowRaw, bool _isMagic, int _scale)
    {
        //canvasSizeDelta = GufengxGameSystem.Instance.gameContext.UIList.GetComponent<RectTransform>().sizeDelta;
        isPaintMagic = _isMagic;
        totalShowRaw = _totalShowRaw;
        brushTypeTexture = _brushType;
        raw_paint = _raw;

        //if (_scale != 1)
        //{
        //    Vector2 _size = raw_paint.GetComponent<RectTransform>().sizeDelta;
        //    _size.x = canvasSizeDelta.x * _scale;
        //    raw_paint.GetComponent<RectTransform>().sizeDelta = _size;
        //    Vector3 recordPos = raw_paint.transform.localPosition;
        //    recordPos.x = (_size.x - canvasSizeDelta.x) / 2.0f;
        //