工程截图

CorrosionEffect.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
/// <summary>
/// 腐蚀效果
/// </summary>
public class CorrosionEffect : MonoBehaviour
{
    [SerializeField]
    private RawImage m_RawImage;
    //定义结构元素(Sturcture Element),即模板
    //模板可以定义成各种形状，用1表示有效区域,不同的模板形状产生的效果不同。
    private int[,] SE;
    private int SE_W, SE_H;//模板宽，高

    [SerializeField]
    private SturctureElement m_SturctureElement;
    //定义模板类型
    public enum SturctureElement
    {
        SE_3X3,
        SE_4X4,
        SE_5X5_PRISMATIC
    }

    private void Awake()
    {
        switch (m_SturctureElement)
        {
            case SturctureElement.SE_3X3:
                SE = new int[,] { 
                    { 1, 1, 1 }, 
                    { 1, 1, 1 }, 
                    { 1, 1, 1 } };
                SE_W = 3;
                SE_H = 3;
                break;
            case SturctureElement.SE_4X4:
                SE = new int[,] { 
                    { 1, 1, 1, 1 },
                    { 1, 1, 1, 1 }, 
                    { 1, 1, 1, 1 },
                    { 1, 1, 1, 1 }};
                SE_W = 4;
                SE_H = 4;
                break;
            case SturctureElement.SE_5X5_PRISMATIC: //5x5棱形
                SE = new int[,] {
                    { 0, 0, 1, 0, 0 },
                    { 0, 1, 1, 1, 0 },
                    { 1, 1, 1, 1, 1 },
                    { 0, 1, 1, 1, 0 },
                    { 0, 0, 1, 0, 0 }};
                SE_W = 5;
                SE_H = 5;
                break;
        }
    }

    void Start()
    {
        Corrode();
    }

    /// <summary>
    /// 腐蚀
    /// </summary>
    public void Corrode()
    {
        Texture2D tex = m_RawImage.texture as Texture2D;
        if (tex == null)
            return;
        Texture2D newTex = new Texture2D(tex.width, tex.height);
        newTex.SetPixels( tex.GetPixels() );
        int rowCount = tex.height - SE_H;
        int columnCount = tex.width - SE_W;
        //用模板去扫描Texture的每一行
        for (int y=0; y < rowCount; y += 1)
        {
            //扫描一行
            for (int x = 0; x < columnCount; x += 1)
            {
                if (!HitWhite(x, y, SE_W, SE_H, tex))
                    continue;
                //腐蚀原理: 模板形状覆盖区发现白色，则将整个模板形状区设置成白色
                SetAreaColor(x, y, SE_W, SE_H, Color.white, newTex);
            }
        }
        newTex.Apply();
        m_RawImage.texture = newTex;
    }

    //模板覆盖区是否存在白色 (对黑色进行腐蚀)
    private bool HitWhite(int x, int y, int blockWidth, int blockHeight, Texture2D tex)
    {
        for (int i=x, tx=0; i<x+blockWidth; i++, tx++)
        {
            for (int j=y, ty=0; j<y+blockHeight; j++, ty++)
            {
                if (SE[tx,ty] == 0)
                    continue;//不在模板形状内

                Color c = tex.GetPixel(i, j);
                //粗略判断
                if (c.r > 0.5f && c.g > 0.5f && c.b > 0.5f)
                {
                    return true;
                }
            }
        }
        return false;
    }

    //设置模板形状所覆盖的区域颜色
    private void SetAreaColor(int x, int y, int blockWidth, int blockHeight, Color color, Texture2D tex)
    {
        int size = blockWidth * blockHeight;
        Color[] colors = new Color[size];
        for (int i = 0; i < size; i++)
            colors[i] = color;
        for (int i=0; i<blockHeight; i++)
        {
            for (int j=0; j<blockWidth; j++)
            {
                if (SE[i, j] == 0)
                    continue;
                tex.SetPixel(x+j, y+i, color);
            }
        }
    }
}

运行效果