彩色图生成灰度图与分离alpha通道

彩色图片生成对应灰度图

using UnityEngine;
using System.Collections;

public class TestPicture : MonoBehaviour {
    public Texture2D srcTex;
    public float fadeLevel = 0;
　　//生成灰度图
    [ContextMenu("GenerateGrayTex")]
    void GenerateGrayTex() {
        if (null == srcTex) {
            return;
        }
        Texture2D destTex = new Texture2D(srcTex.width, srcTex.height);
        Color32[] destColor = srcTex.GetPixels32();
        for (int index = 0; index < destColor.Length; index++) {
            float c = (destColor[index].g + destColor[index].b + destColor[index].r) / 3f;
            destColor[index].r = System.BitConverter.GetBytes((int)(destColor[index].r * fadeLevel + c * (1 - fadeLevel)))[0];
            destColor[index].g = System.BitConverter.GetBytes((int)(destColor[index].g * fadeLevel + c * (1 - fadeLevel)))[0];
            destColor[index].b = System.BitConverter.GetBytes((int)(destColor[index].b * fadeLevel + c * (1 - fadeLevel)))[0];
        }
        destTex.SetPixels32(destColor);
        string path = string.Format("{0}/_Test/Picture/dest.png", Application.dataPath);
        System.IO.File.WriteAllBytes(path,destTex.EncodeToJPG());
        UnityEditor.AssetDatabase.Refresh();
    }
　　//提前alpha通道
    [ContextMenu("GenerateGrayAlphaTex")]
    void GenerateGrayAlphaTex()
    {
        if (null == srcTex)
        {
            return;
        }
        Texture2D destTex = new Texture2D(srcTex.width, srcTex.height);
        Color32[] destColor = srcTex.GetPixels32();
        for (int index = 0; index < destColor.Length; index++)
        {
            destColor[index].r = (destColor[index].a);
            destColor[index].g = (destColor[index].a);
            destColor[index].b = (destColor[index].a);
            destColor[index].a = 0;
        }
        destTex.SetPixels32(destColor);
        string path = string.Format("{0}/_Test/Picture/liuyifei.alpha.png", Application.dataPath);
        System.IO.File.WriteAllBytes(path, destTex.EncodeToJPG());
        UnityEditor.AssetDatabase.Refresh();
    }
}