尝试从 setpixel/getpixel 进行优化

Question

我正在尝试优化以下代码，因为循环多次以获取纹理的每个像素非常耗时！

我有 3 个纹理，在其他地方生成，需要合并然后保存到磁盘。

我尝试过使用 SetPixels 和 GetPixels，但这并不是特别有用，因为多次使用它只会替换整个纹理，而不仅仅是替换非透明像素。以下是我目前的功能：

public void savePNG()
{

    stationWidth = PlayerPrefs.GetInt("Station Width");
    stationHeight = PlayerPrefs.GetInt("Station Height");

    Debug.Log(stationWidth + ", " + stationHeight);

    Texture2D spaceStation = new Texture2D(stationWidth*256, stationHeight*256, TextureFormat.ARGB32, false);
    spaceStation = new Texture2D(stationWidth*256, stationHeight*256, TextureFormat.ARGB32, false);

    Color Test;

    floorTex = new Texture2D(stationWidth*256, stationHeight*256, TextureFormat.ARGB32, false);
    wallTex = new Texture2D(stationWidth*256, stationHeight*256, TextureFormat.ARGB32, false);
    roomTex = new Texture2D(stationWidth*256, stationHeight*256, TextureFormat.ARGB32, false);

    floorTex.LoadImage(File.ReadAllBytes(Application.dataPath + "/../floorTexture.png"), false);
    wallTex.LoadImage(File.ReadAllBytes(Application.dataPath + "/../wallTexture.png"), false);
    roomTex.LoadImage(File.ReadAllBytes(Application.dataPath + "/../roomTexture.png"), false);


    for(int row = 0; row < stationWidth*256; row ++)
    {
        for(int col = 0; col < stationHeight*256; col ++)
        {

            Test = floorTex.GetPixel(row,col);

            if(Test.a != 0.0f)
            {
                spaceStation.SetPixel(row, col, floorTex.GetPixel(row,col));
            }
            else
            {
                spaceStation.SetPixel(row, col, Color.white);
            }

            Test = wallTex.GetPixel(row,col);

            if(Test.a != 0.0f)
            {
                spaceStation.SetPixel(row, col, wallTex.GetPixel(row,col));
            }

            Test = roomTex.GetPixel(row,col);

            if(Test.a != 0.0f)
            {
                spaceStation.SetPixel(row, col, roomTex.GetPixel(row,col));
            }

        }
    }

    spaceStation.Apply();

    byte[] bytes = spaceStation.EncodeToPNG();
    File.WriteAllBytes(Application.dataPath + "/../SpaceStation.png", bytes);

}

我不知道从哪里开始，任何想法或建议将不胜感激！

附加

我尝试的 GetPixels 和 SetPixels 代码如下所示：

    spaceStation.SetPixels(floorTex.GetPixels(0, 0, stationWidth*256, stationHeight*256));
    spaceStation.SetPixels(wallTex.GetPixels(0 ,0, stationWidth*256, stationHeight*256));
    spaceStation.SetPixels(roomTex.GetPixels(0, 0, stationWidth*256, stationHeight*256));

每个 SetPixels 都完全覆盖了以前的那些，我希望透明像素根本不覆盖任何像素，这样细节就会显示出来

Answer 1

我使用颜色数组而不是单独设置每个像素，只需要调用 GetPixels 3 次和 SetPixels 一次。功能现在快了大约 80%，这在所有方面都相当不错。有人告诉我，使用Graphics.Blit 和着色器可以获得更好的结果，但我真的对着色器一无所知，所以目前我不会采用这种方法。下面是代码现在的样子：

public void savePNG()
{
    stationWidth = PlayerPrefs.GetInt("Station Width");
    stationHeight = PlayerPrefs.GetInt("Station Height");

    Texture2D spaceStation = new Texture2D(stationWidth*256, stationHeight*256, TextureFormat.ARGB32, false);
    spaceStation = new Texture2D(stationWidth*256, stationHeight*256, TextureFormat.ARGB32, false);

    Color[] mainArray = new Color[(stationWidth*256)*(stationHeight*256)];
    Color[] wallArray = new Color[(stationWidth*256)*(stationHeight*256)];
    Color[] roomArray = new Color[(stationWidth*256)*(stationHeight*256)];

    floorTex = new Texture2D(stationWidth*256, stationHeight*256, TextureFormat.ARGB32, false);
    wallTex = new Texture2D(stationWidth*256, stationHeight*256, TextureFormat.ARGB32, false);
    roomTex = new Texture2D(stationWidth*256, stationHeight*256, TextureFormat.ARGB32, false);

    floorTex.LoadImage(File.ReadAllBytes(Application.dataPath + "/../floorTexture.png"), false);
    wallTex.LoadImage(File.ReadAllBytes(Application.dataPath + "/../wallTexture.png"), false);
    roomTex.LoadImage(File.ReadAllBytes(Application.dataPath + "/../roomTexture.png"), false);


    mainArray = floorTex.GetPixels(0,0,stationWidth*256, stationHeight*256);
    wallArray = wallTex.GetPixels(0,0,stationWidth*256, stationHeight*256);
    roomArray = roomTex.GetPixels(0,0,stationWidth*256, stationHeight*256);

    for(int i = 0; i < mainArray.Length; i++)
    {
        if(wallArray[i].a != 0.0f)
        {
            mainArray[i] = wallArray[i];
        }
        if(roomArray[i].a != 0.0f)
        {
            mainArray[i] = roomArray[i];
        }
    }

    spaceStation.SetPixels(mainArray);

    spaceStation.Apply();

    byte[] bytes = spaceStation.EncodeToPNG();
    File.WriteAllBytes(Application.dataPath + "/../SpaceStation.png", bytes);

}

Answer 2

我真的不知道 Texture2D 对象的 (get/set)Pixel 方法的性能。但在 .NET 世界中，我们更喜欢使用 System.Drawing.Bitmap 对象和 System.Drawing.Imaging.BitmapData 类和 BitmapData 的 Scan0 属性来快速访问像素值。

在 SO 中已经有一个漂亮的 answer 演示了用法。