带有双指针的System.AccessViolationException？

Question

我想在托管代码中将纹理压缩到pvrtc，所以我找到了一个可以满足我想要的源，但是我得到了一个System.AccessViolationException。这是我到目前为止使用的代码：

[DllImport("x86/pvrtc.dll", CallingConvention = CallingConvention.StdCall)]
private static extern IntPtr CompressTexture(byte[] data, int height, int width, int mipLevels, bool preMultiplied, bool pvrtc4bppCompression, ref IntPtr dataSizes);

public static byte[] Compress(byte[] data, int height, int width, int mipLevels, bool preMultiplied, bool pvrtc4bppCompression)
{
    IntPtr dataSizesPtr = Marshal.AllocCoTaskMem(data.Length + 1);

    var texDataPtr = CompressTexture(data, height, width, mipLevels, preMultiplied, pvrtc4bppCompression, ref dataSizesPtr);
    //Store the size of each mipLevel
    var dataSizesArray = new int[mipLevels];
    //Copies data from an unmanaged memory pointer to a managed 8-bit unsigned integer array.
    Marshal.Copy(dataSizesPtr, dataSizesArray, 0, dataSizesArray.Length);
    var levelSize = 0;
    byte[] levelData = new byte[0];

    for (int x = 0; x < mipLevels; x++)
    {
        levelSize = dataSizesArray[x];
        levelData = new byte[levelSize];

        Marshal.Copy(texDataPtr, levelData, 0, levelSize);

        texDataPtr = IntPtr.Add(texDataPtr, levelSize);
    }
    return levelData;
}

非常感谢任何帮助。