public static byte[] GenerateMipmaps(RGBImage image)
{
int width = image.Width;
int height = image.Height;
if (!MathUtils.IsPowerOfTwo(width) || !MathUtils.IsPowerOfTwo(height))
{
throw new Exception("Image dimensions must by power of 2");
}
long size = ComputeTextureSize(width, height, TextureCompressionFormat.Uncompressed);
byte[] result = new byte[size];
image.CopyRawData(result);
Debug.Log($"Generated level {0} mipmap ({image.Size} bytes, width: {width}, height: {height})");
GenerateMipmaps(image, result, image.Size, 1);
return(result);
}
private static void GenerateMipmaps(RGBImage image, byte[] result, long resultIndex, int level)
{
int mipWidth = MathUtils.Clamp(image.Width >> 1, 1);
int mipHeight = MathUtils.Clamp(image.Height >> 1, 1);
RGBImage mipImage = new RGBImage(mipWidth, mipHeight);
for (int x = 0; x < mipWidth; x++)
{
for (int y = 0; y < mipHeight; y++)
{
mipImage.SetPixel(x, y, image.GetAverage(x << 1, y << 1, 2, ImageBoundaryMode.Wrap));
}
}
mipImage.CopyRawData(result, resultIndex);
Debug.Log($"Generated level {level++} mipmap ({mipImage.Size} bytes, width: {mipWidth}, height: {mipHeight})");
if (mipWidth == 1 && mipHeight == 1)
{
return;
}
GenerateMipmaps(mipImage, result, mipImage.Size + resultIndex, level);
}