崩坏学园2及大部分采用ETC1压缩格式的Unity3D游戏的拆包图处理

 1 private Bitmap mergeImageOld(Bitmap rgbTexture,Bitmap alphaTexture)
 2 {
 3     textureWithAlpha = new Bitmap(rgbTexture.Width, rgbTexture.Height, System.Drawing.Imaging.PixelFormat.Format32bppArgb); //新建一个与RGB同分辨率的Bitmap
 4     try
 5     {
 6         for (int i = 0; i < rgbTexture.Width; i++)
 7         {
 8             for (int j = 0; j < rgbTexture.Height; j++)
 9             {
10                 Color withAlpha = Color.FromArgb(alphaTexture.GetPixel(i, j).R, rgbTexture.GetPixel(i, j));
11                 textureWithAlpha.SetPixel(i, j, withAlpha);
12             }   //internal for end
13         }   //for end
14 
15         return textureWithAlpha;
16     }
17     catch(Exception ex)
18     {
19         Console.WriteLine(ex.Message);
20         return textureWithAlpha;
21     }
22 }   //mergeImageOld()

Color Color.FromArgb(int alpha,Color baseColor);

 1 public unsafe Bitmap mergeImage(Bitmap rgbTexture,Bitmap alphaTexture)
 2 {
 3     int width = rgbTexture.Width;
 4     int height = rgbTexture.Height;
 5 
 6     try
 7     {
 8         BitmapData textureWithAlphaData = rgbTexture.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.ReadWrite, PixelFormat.Format32bppArgb);    //将图像锁定到内存中以便操作
 9         BitmapData alphaTextureData = alphaTexture.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.ReadWrite, PixelFormat.Format32bppArgb);
10 
11         byte* resultP = (byte*)textureWithAlphaData.Scan0;  //获取在内存的中首地址
12         byte* alphaP = (byte*)alphaTextureData.Scan0;
13 
14         for (int j = 0; j < height; j++)
15         {
16             for (int i = 0; i < width; i++)
17             {
18                 resultP[3] = alphaP[2]; //ARBG在内存中存储顺序为GBRA 所以resultP[3]即为Alpha分量  resultP[2]即为红色分量 
19                 resultP += 4;   //下移4个位置 处理下一个像素的信息
20                 alphaP += 4;
21             }
22         }
23 
24         rgbTexture.UnlockBits(textureWithAlphaData);    //解锁
25         alphaTexture.UnlockBits(alphaTextureData);
26 
27         return rgbTexture;
28     }
29     catch
30     {
31         return rgbTexture;
32     }
33 }   //mergeImage()

1 rgbTexture.Dispose();
2 alphaTexture.Dispose();
3 textureWithAlpha.Dispose();

 1 byte* resultP = (byte*)textureWithAlphaData.Scan0;  //获取在内存的中首地址
 2 byte* alphaP = (byte*)alphaTextureData.Scan0;
 3 
 4 int resultOffset = textureWithAlphaData.Stride - width * 3; //用实际占位过的长度来减去图片每行有效像素占用的长度  此行代码仅对24位图有效
 5 int alphaOffset = textureWithAlphaData.Stride - width * 3;
 6 
 7 for (int j = 0; j < height; j++)
 8 {
 9     for (int i = 0; i < width; i++)
10     {
11         resultP[2] = alphaP[2]; //RBG在内存中存储顺序为GBR  这里仅仅举栗子方便对比  这行代码跑过之后会将2图的红色分量设置到1图中去
12         resultP += 3;   //下移3个位置 处理下一个像素的信息
13         alphaP += 3;
14     }
15     resultP += resultOffset;    //由于上面用的是图片的宽度  所以现在指针停在了占位字节的前面  所以这里需要跳过多出的字节
16     alphaP += alphaOffset;
17 }