/// <summary>
/// Loads the specified compressed image (in <see cref="BLP"/> format) into a native OpenGL texture.
/// </summary>
/// <param name="textureID">The ID of the texture to load the image into.</param>
/// <param name="compressedImage">The compressed image to load.</param>
/// <exception cref="ArgumentException">
/// Thrown if the image format does not match the pixel format.
/// </exception>
/// <exception cref="ArgumentNullException">
/// Thrown if the input image is null.
/// </exception>
private static void LoadDXTTexture(int textureID, BLP compressedImage)
{
if (compressedImage == null)
{
throw new ArgumentNullException(nameof(compressedImage));
}
GL.BindTexture(TextureTarget.Texture2D, textureID);
// Load the set of raw compressed mipmaps
for (uint i = 0; i < compressedImage.GetMipMapCount(); ++i)
{
byte[] compressedMipMap = compressedImage.GetRawMipMap(i);
Resolution mipResolution = compressedImage.GetMipLevelResolution(i);
PixelInternalFormat compressionFormat;
switch (compressedImage.GetPixelFormat())
{
case BLPPixelFormat.DXT1:
{
compressionFormat = PixelInternalFormat.CompressedRgbaS3tcDxt1Ext;
break;
}
case BLPPixelFormat.DXT3:
{
compressionFormat = PixelInternalFormat.CompressedRgbaS3tcDxt3Ext;
break;
}
case BLPPixelFormat.DXT5:
{
compressionFormat = PixelInternalFormat.CompressedRgbaS3tcDxt5Ext;
break;
}
default:
{
throw new ArgumentException($"Image format (DXTC) did not match pixel format: {compressedImage.GetPixelFormat()}", nameof(Image));
}
}
// Load the mipmap into the texture
GL.CompressedTexImage2D(TextureTarget.Texture2D, (int)i,
compressionFormat,
(int)mipResolution.X,
(int)mipResolution.Y,
0,
compressedMipMap.Length,
compressedMipMap);
}
}
