/// <summary>
/// Decodes DXT data to ARGB.
/// </summary>
private static byte[] DecodeDXTToARGB(int DXTVersion, byte[] compressedData, uint width, uint height, DDSPixelFormat pixelFormat, uint mipmapCount)
{
bool alphaFlag = Utils.ContainsBitFlags(pixelFormat.flags, (uint)DDSPixelFormatFlags.AlphaPixels);
bool containsAlpha = alphaFlag || ((pixelFormat.RGBBitCount == 32) && (pixelFormat.ABitMask != 0));
var reader = new UnityBinaryReader(new MemoryStream(compressedData));
var argb = new byte[TextureUtils.CalculateMipMappedTextureDataSize((int)width, (int)height, 4)];
int mipMapWidth = (int)width;
int mipMapHeight = (int)height;
int baseARGBIndex = 0;
for (int mipMapIndex = 0; mipMapIndex < mipmapCount; mipMapIndex++)
{
for (int rowIndex = 0; rowIndex < mipMapHeight; rowIndex += 4)
{
for (int columnIndex = 0; columnIndex < mipMapWidth; columnIndex += 4)
{
Color32[] colors = null;
// Doing a switch instead of using a delegate for speed.
switch (DXTVersion)
{
case 1:
colors = DecodeDXT1TexelBlock(reader, containsAlpha);
break;
case 3:
colors = DecodeDXT3TexelBlock(reader);
break;
case 5:
colors = DecodeDXT5TexelBlock(reader);
break;
default:
throw new NotImplementedException("Tried decoding a DDS file using an unsupported DXT format: DXT" + DXTVersion.ToString());
}
CopyDecodedTexelBlock(colors, argb, baseARGBIndex, rowIndex, columnIndex, mipMapWidth, mipMapHeight);
}
}
baseARGBIndex += (mipMapWidth * mipMapHeight * 4);
mipMapWidth /= 2;
mipMapHeight /= 2;
}
return(argb);
}
/// <summary>
/// Decodes DXT data to ARGB.
/// </summary>
static byte[] DecodeDXTToARGB(int DXTVersion, byte[] compressedData, uint width, uint height, DDSPixelFormat pixelFormat, uint mipmapCount)
{
var alphaFlag = Utils.ContainsBitFlags((int)pixelFormat.dwFlags, (int)DDSPixelFormats.AlphaPixels);
var containsAlpha = alphaFlag || (pixelFormat.dwRGBBitCount == 32 && pixelFormat.dwABitMask != 0);
using (var r = new BinaryFileReader(new MemoryStream(compressedData)))
{
var argb = new byte[TextureUtils.CalculateMipMappedTextureDataSize((int)width, (int)height, 4)];
var mipMapWidth = (int)width;
var mipMapHeight = (int)height;
var baseARGBIndex = 0;
for (var mipMapIndex = 0; mipMapIndex < mipmapCount; mipMapIndex++)
{
for (var rowIndex = 0; rowIndex < mipMapHeight; rowIndex += 4)
{
for (var columnIndex = 0; columnIndex < mipMapWidth; columnIndex += 4)
{
if (r.Position == r.BaseStream.Length)
{
return(argb);
}
Color32[] colors = null;
switch (DXTVersion) // Doing a switch instead of using a delegate for speed.
{
case 1: colors = DecodeDXT1TexelBlock(r, containsAlpha); break;
case 3: colors = DecodeDXT3TexelBlock(r); break;
case 5: colors = DecodeDXT5TexelBlock(r); break;
default: throw new NotImplementedException($"Tried decoding a DDS file using an unsupported DXT format: DXT {DXTVersion}");
}
CopyDecodedTexelBlock(colors, argb, baseARGBIndex, rowIndex, columnIndex, mipMapWidth, mipMapHeight);
}
}
baseARGBIndex += mipMapWidth * mipMapHeight * 4;
mipMapWidth /= 2;
mipMapHeight /= 2;
}
return(argb);
}
}
/// <summary>
/// Extracts a DDS file's texture format and pixel data.
/// </summary>
static void ExtractDDSTextureFormatAndData(DDSHeader header, GenericReader r, out bool hasMipmaps, out uint DDSMipmapLevelCount, out TextureFormat textureFormat, out int bytesPerPixel, out byte[] textureData)
{
hasMipmaps = Utils.ContainsBitFlags((int)header.dwCaps, (int)DDSCaps.Mipmap);
// Non-mipmapped textures still have one mipmap level: the texture itself.
DDSMipmapLevelCount = hasMipmaps ? header.dwMipMapCount : 1;
// If the DDS file contains uncompressed data.
if (Utils.ContainsBitFlags((int)header.ddspf.dwFlags, (int)DDSPixelFormats.RGB))
{
// some permutation of RGB
if (!Utils.ContainsBitFlags((int)header.ddspf.dwFlags, (int)DDSPixelFormats.AlphaPixels))
{
throw new NotImplementedException("Unsupported DDS file pixel format.");
}
// some permutation of RGBA
else
{
// There should be 32 bits per pixel.
if (header.ddspf.dwRGBBitCount != 32)
{
throw new FileFormatException("Invalid DDS file pixel format.");
}
// BGRA32
if (header.ddspf.dwBBitMask == 0x000000FF && header.ddspf.dwGBitMask == 0x0000FF00 && header.ddspf.dwRBitMask == 0x00FF0000 && header.ddspf.dwABitMask == 0xFF000000)
{
textureFormat = TextureFormat.BGRA32;
bytesPerPixel = 4;
}
// ARGB32
else if (header.ddspf.dwABitMask == 0x000000FF && header.ddspf.dwRBitMask == 0x0000FF00 && header.ddspf.dwGBitMask == 0x00FF0000 && header.ddspf.dwBBitMask == 0xFF000000)
{
textureFormat = TextureFormat.ARGB32;
bytesPerPixel = 4;
}
else
{
throw new NotImplementedException("Unsupported DDS file pixel format.");
}
if (!hasMipmaps)
{
textureData = new byte[header.dwPitchOrLinearSize * header.dwHeight];
}
// Create a data buffer to hold all mipmap levels down to 1x1.
else
{
textureData = new byte[TextureUtils.CalculateMipMappedTextureDataSize((int)header.dwWidth, (int)header.dwHeight, bytesPerPixel)];
}
r.ReadRestOfBytes(textureData, 0);
}
}
else if ("DXT1".EqualsASCIIBytes(header.ddspf.dwFourCC))
{
textureFormat = TextureFormat.ARGB32;
bytesPerPixel = 4;
var compressedTextureData = r.ReadRestOfBytes();
textureData = DecodeDXT1ToARGB(compressedTextureData, header.dwWidth, header.dwHeight, header.ddspf, DDSMipmapLevelCount);
}
else if ("DXT3".EqualsASCIIBytes(header.ddspf.dwFourCC))
{
textureFormat = TextureFormat.ARGB32;
bytesPerPixel = 4;
var compressedTextureData = r.ReadRestOfBytes();
textureData = DecodeDXT3ToARGB(compressedTextureData, header.dwWidth, header.dwHeight, header.ddspf, DDSMipmapLevelCount);
}
else if ("DXT5".EqualsASCIIBytes(header.ddspf.dwFourCC))
{
textureFormat = TextureFormat.ARGB32;
bytesPerPixel = 4;
var compressedTextureData = r.ReadRestOfBytes();
textureData = DecodeDXT5ToARGB(compressedTextureData, header.dwWidth, header.dwHeight, header.ddspf, DDSMipmapLevelCount);
}
else
{
throw new NotImplementedException("Unsupported DDS file pixel format.");
}
}
