RasterImage GetDXT1RasterImage()
{
//open stream and read file data
MemoryStream mStream = new MemoryStream(FileData);
mStream.ReadBytes(6); //skip
byte compression = mStream.ReadByte(); //Compression Type
if (compression == 4) //DXT1
{
int mipLevels = mStream.ReadByte(); //number of Miplevels
//get header values
int imageWidth = BitConverter.ToInt32(mStream.ReadBytes(4), 0);
int imageHeight = BitConverter.ToInt32(mStream.ReadBytes(4), 0);
int offset = BitConverter.ToInt32(mStream.ReadBytes(4), 0);
int dataLenght = BitConverter.ToInt32(mStream.ReadBytes(4), 0);
//Get pixeldata
mStream.SetPosition(offset);
RasterImage image = new RasterImage(imageWidth, imageHeight);
int xOffset = 0;
int yOffset = 0;
for (int i = 0; i < dataLenght; i += 8)
{
//Get 4 colors
UInt16 iC0 = BitConverter.ToUInt16(mStream.ReadBytes(2), 0); //16bit Color c0 5:6:5 RGB
UInt16 iC1 = BitConverter.ToUInt16(mStream.ReadBytes(2), 0); //16bit Color c1 5:6:5 RGB
Color[] colors = GetColorsFromDXTFormat(iC0, iC1, true); //Calculate the 4 colors
//Get 4x4 Pixelblock and set Pixels in bitmap
for (int y = 0; y < 4; y++)
{
List <byte> pointerBits = new List <byte>(ByteAnalyzer.GetBitsFromNumber((int)mStream.ReadByte()));//byte holding 4 2bit Color pointers
for (int x = 0; x < 4; x++)
{
int colorPointer = ByteAnalyzer.GetIntFromBits(pointerBits.GetRange(x * 2, 2).ToArray());//Pointer for pixel
image.SetPixel(xOffset + x, yOffset + y, colors[colorPointer]);
}
}
// set xOffset and yOffset values
if (xOffset + 4 < imageWidth)
{
xOffset += 4;
}
else
{
xOffset = 0;
yOffset += 4;
}
}
return(image);
}
else
{
return(null);
}
}
Color[] GetColorsFromDXTFormat(UInt16 iC0, UInt16 iC1, bool DXT1)
{
//Get 4 colors
List <byte> bitsC0 = new List <byte>(ByteAnalyzer.GetBitsFromNumber((int)iC0)); //List of bit values as bytes 0 and 1;
List <byte> bitsC1 = new List <byte>(ByteAnalyzer.GetBitsFromNumber((int)iC1)); //List of bit values as bytes 0 and 1;
Color[] colors = new Color[4];
byte[] bits = bitsC0.GetRange(0, 5).ToArray(); //Blue bits
byte b0 = (byte)((float)ByteAnalyzer.GetIntFromBits(bits) / 31 * 255); //Convert to byte
bits = bitsC0.GetRange(5, 6).ToArray(); //Green bits
byte g0 = (byte)((float)ByteAnalyzer.GetIntFromBits(bits) / 63 * 255); //Convert to byte
bits = bitsC0.GetRange(11, 5).ToArray(); //Red bits
byte r0 = (byte)((float)ByteAnalyzer.GetIntFromBits(bits) / 31 * 255); //Convert to byte
colors[0] = Color.FromArgb(r0, g0, b0);
bits = bitsC1.GetRange(0, 5).ToArray(); //Blue bits
byte b1 = (byte)((float)ByteAnalyzer.GetIntFromBits(bits) / 31 * 255); //Convert to byte
bits = bitsC1.GetRange(5, 6).ToArray(); //Green bits
byte g1 = (byte)((float)ByteAnalyzer.GetIntFromBits(bits) / 63 * 255); //Convert to byte
bits = bitsC1.GetRange(11, 5).ToArray(); //Red bits
byte r1 = (byte)((float)ByteAnalyzer.GetIntFromBits(bits) / 31 * 255); //Convert to byte
colors[1] = Color.FromArgb(r1, g1, b1);
//Calculate Colors c2 and c3
if (iC0 > iC1 || !DXT1)
{
byte b2 = (byte)((float)b0 / 3 * 2 + (float)b1 / 3);
byte g2 = (byte)((float)g0 / 3 * 2 + (float)g1 / 3);
byte r2 = (byte)((float)r0 / 3 * 2 + (float)r1 / 3);
colors[2] = Color.FromArgb(r2, g2, b2);
byte b3 = (byte)((float)b0 / 3 + (float)b1 / 3 * 2);
byte g3 = (byte)((float)g0 / 3 + (float)g1 / 3 * 2);
byte r3 = (byte)((float)r0 / 3 + (float)r1 / 3 * 2);
colors[3] = Color.FromArgb(r3, g3, b3);
}
else
{
byte b2 = (byte)((float)b0 / 2 + (float)b1 / 2);
byte g2 = (byte)((float)g0 / 2 + (float)g1 / 2);
byte r2 = (byte)((float)r0 / 2 + (float)r1 / 2);
colors[2] = Color.FromArgb(r2, g2, b2);
colors[3] = Color.FromArgb(0, 0, 0, 0);
}
return(colors);
}
RasterImage GetDXT3RasterImage()
{
//open stream and read file data
MemoryStream mStream = new MemoryStream(FileData);
mStream.ReadBytes(6); //skip
byte compression = mStream.ReadByte(); //Compression Type
if (compression == 8) //DXT3
{
int mipLevels = mStream.ReadByte(); //number of Miplevels
//get header values
int imageWidth = BitConverter.ToInt32(mStream.ReadBytes(4), 0);
int imageHeight = BitConverter.ToInt32(mStream.ReadBytes(4), 0);
int offset = BitConverter.ToInt32(mStream.ReadBytes(4), 0);
int dataLenght = BitConverter.ToInt32(mStream.ReadBytes(4), 0);
//Get pixeldata
mStream.SetPosition(offset);
RasterImage image = new RasterImage(imageWidth, imageHeight);
int xOffset = 0;
int yOffset = 0;
for (int i = 0; i < dataLenght; i += 16)
{
//Get Alpha values
List <byte> alphaBytes = new List <byte>(mStream.ReadBytes(8));
//Get 4 colors
UInt16 iC0 = BitConverter.ToUInt16(mStream.ReadBytes(2), 0); //16bit Color c0 5:6:5 RGB
UInt16 iC1 = BitConverter.ToUInt16(mStream.ReadBytes(2), 0); //16bit Color c1 5:6:5 RGB
Color[] colors = GetColorsFromDXTFormat(iC0, iC1, false); //Calculate the 4 colors
//Get 4x4 Pixelblock and set Pixels in bitmap
for (int y = 0; y < 4; y++)
{
List <byte> pointerBits = new List <byte>(ByteAnalyzer.GetBitsFromNumber((int)mStream.ReadByte())); //Convert byte holding 4 2bit Color pointers to bit list
List <byte> alphaBits = new List <byte>(ByteAnalyzer.GetBitsFromNumber((alphaBytes[y * 2]))); //Convert bytes holding 2 4bit Alpha value each, to bit list
alphaBits.AddRange(ByteAnalyzer.GetBitsFromNumber(alphaBytes[y * 2 + 1])); //Add secon Byte-bits
for (int x = 0; x < 4; x++)
{
int colorPointer = ByteAnalyzer.GetIntFromBits(pointerBits.GetRange(x * 2, 2).ToArray()); //Pointer for pixel
byte alpha = (byte)((float)ByteAnalyzer.GetIntFromBits(alphaBits.GetRange(x * 4, 4).ToArray()) / 15 * 255); //Calulate alpha value byte
Color color = Color.FromArgb(alpha, colors[colorPointer].R, colors[colorPointer].G, colors[colorPointer].B);
image.SetPixel(xOffset + x, yOffset + y, color);
}
}
// set xOffset and yOffset values
if (xOffset + 4 < imageWidth)
{
xOffset += 4;
}
else
{
xOffset = 0;
yOffset += 4;
}
}
return(image);
}
else
{
return(null);
}
}
