public void SaveAsPng(Stream stream, int width, int height)
{
int len = Width * Height * GetFormatSize(Format);
IntPtr data = Marshal.AllocHGlobal(len);
FNA3D.FNA3D_GetTextureData2D(
GraphicsDevice.GLDevice,
texture,
0,
0,
Width,
height,
0,
data,
len
);
FNA3D.WritePNGStream(
stream,
Width,
Height,
width,
height,
data
);
Marshal.FreeHGlobal(data);
}