c# - 调用 Texture2D.readPixels 时 iOS 挂起

Question

我试图将 RenderTexture 绘制到 Texture2D 中，目的是将其保存到磁盘。这种方法在 OSX 编辑器和 Android 上一直有效。

我在 XCode 控制台中没有看到任何错误，当我调用 Texture2D.ReadPixels() 时，我的应用程序变得完全卡住

这里是代码的总结:

    // declaring variables...
    RenderTexture outputTexture;
    RenderTextureFormat RTFormat = RenderTextureFormat.ARGB32;

    // use an appropriate format for render textures
    if(SystemInfo.SupportsRenderTextureFormat(RenderTextureFormat.ARGBFloat)){
        RTFormat = RenderTextureFormat.ARGBFloat;
    }else if(SystemInfo.SupportsRenderTextureFormat(RenderTextureFormat.ARGBHalf)){
        RTFormat = RenderTextureFormat.ARGBHalf;
    }

    // create instance of output texture
    outputTexture = new RenderTexture (res.x, res.y, 0, RTFormat);

    // in Update, draw stuff to outputTexture
    Graphics.Blit (outputTexture, canvasTexture);
    Graphics.Blit (canvasTexture, outputTexture, material);

    // later... user wants to save the image
    // draw rendertexture to a Texture2D so we can write to disk
    RenderTexture.active = outputTexture;
    tmpTexture = new Texture2D (outputTexture.width, outputTexture.height, TextureFormat.ARGB32, false);
    tmpTexture.ReadPixels (new Rect (0, 0, outputTexture.width, outputTexture.height), 0, 0, false);
    tmpTexture.Apply ();
    RenderTexture.active = null;

我尝试过使用各种RenderTextureFormat 和TextureFormat，但似乎没有任何效果!

Answer 1

我相信这是由您的渲染纹理格式调用引起的。之前也发生过类似的事情。

这段代码分配默认纹理格式，然后在当前执行环境支持的情况下更改默认格式(添加了我的注释)

//set a default render texture of  RenderTextureFormat.ARGB32;
RenderTextureFormat RTFormat = RenderTextureFormat.ARGB32;

// if my system supports it, switch to either ARGBFloat or ARGBHalf

// use an appropriate format for render textures
if(SystemInfo.SupportsRenderTextureFormat(RenderTextureFormat.ARGBFloat)){
    RTFormat = RenderTextureFormat.ARGBFloat;
}else if(SystemInfo.SupportsRenderTextureFormat(RenderTextureFormat.ARGBHalf)){
    RTFormat = RenderTextureFormat.ARGBHalf;
}

但是，当您稍后实际定义临时纹理以填充 ReadPixels() 时，您只能以一种方式定义它(同样，我添加了评论)

//define a new tmpTexture container, ALWAYS with a TextureFormat of ARGB32
tmpTexture = new Texture2D (outputTexture.width, outputTexture.height, TextureFormat.ARGB32, false);

因此，在某些系统(无论支持该格式的系统)上，您尝试将 readPixels() 从一种纹理格式转换为另一种纹理格式。这可能是导致您出现问题的原因。

您还可以通过动态更改目标纹理的格式来解决此问题。因此，在第一部分中，您将其更改为:

RenderTextureFormat RTFormat = RenderTextureFormat.ARGB32;

//add another variable here for the destination Texture format
var destinationFormat = TextureFormat.ARGB32;


// use an appropriate format for render textures
if(SystemInfo.SupportsRenderTextureFormat(RenderTextureFormat.ARGBFloat)){
    RTFormat = RenderTextureFormat.ARGBFloat;

    //also set destination format
    destinationFormat = TextureFormat.RGBAFloat;
}else if(SystemInfo.SupportsRenderTextureFormat(RenderTextureFormat.ARGBHalf)){
    RTFormat = RenderTextureFormat.ARGBHalf;

    //also set destination format
    destinationFormat = TextureFormat.RGBAHalf;
}

当然，稍后在声明目标对象时使用动态设置的格式:

//define a new tmpTexture container, with a dynamically set destination format that always matches the input texture
tmpTexture = new Texture2D (outputTexture.width, outputTexture.height, destinationFormat, false);

如果您在评论中仍有问题，请告诉我。