public static int GetSquareTextureSize(FileSystemEntry entry)
{
using (var stream = entry.Open())
using (var reader = new BinaryReader(stream, Encoding.ASCII, true))
{
var header = TgaHeader.Parse(reader);
if (header.Width != header.Height)
{
throw new InvalidOperationException();
}
return(header.Width);
}
}
private static byte[] ReadRunLengthEncodedRgbData(BinaryReader reader, TgaHeader header, int bytesPerPixel)
{
var data = new byte[header.Width * header.Height * bytesPerPixel];
var dataIndex = 0;
while (dataIndex < data.Length)
{
var packet = reader.ReadByte();
var packetType = (RlePacketType)(packet >> 7);
var value = (packet & 0b1111111) + 1;
switch (packetType)
{
case RlePacketType.RawPacket:
{
var bytes = reader.ReadBytes(bytesPerPixel * value);
Array.Copy(bytes, 0, data, dataIndex, bytes.Length);
dataIndex += bytes.Length;
break;
}
case RlePacketType.RunLengthEncodedPacket:
{
var bytes = reader.ReadBytes(bytesPerPixel);
for (var i = 0; i < value; i++)
{
Array.Copy(bytes, 0, data, dataIndex, bytes.Length);
dataIndex += bytes.Length;
}
break;
}
default:
throw new InvalidOperationException();
}
}
return(data);
}
public static TgaFile FromFileSystemEntry(FileSystemEntry entry)
{
using (var stream = entry.Open())
using (var reader = new BinaryReader(stream, Encoding.ASCII, true))
{
var header = TgaHeader.Parse(reader);
if (header.HasColorMap || header.ImageType != TgaImageType.UncompressedRgb)
{
throw new NotSupportedException();
}
var bytesPerPixel = header.ImagePixelSize / 8;
var stride = header.Width * bytesPerPixel;
var data = reader.ReadBytes(header.Width * header.Height * bytesPerPixel);
// Invert y, because data is stored bottom-up in TGA.
var invertedData = new byte[data.Length];
var invertedY = 0;
for (var y = header.Height - 1; y >= 0; y--)
{
Array.Copy(
data,
y * stride,
invertedData,
invertedY * stride,
stride);
invertedY++;
}
return(new TgaFile
{
Header = header,
Data = invertedData
});
}
}
public static TgaFile FromFileSystemEntry(FileSystemEntry entry)
{
using (var stream = entry.Open())
using (var reader = new BinaryReader(stream, Encoding.ASCII, true))
{
var header = TgaHeader.Parse(reader);
if (header.HasColorMap)
{
throw new NotSupportedException("TGA files with color maps are not supported.");
}
switch (header.ImageType)
{
case TgaImageType.UncompressedRgb:
case TgaImageType.UncompressedBlackAndWhite:
case TgaImageType.RunLengthEncodedRgb:
break;
default:
throw new NotSupportedException($"TGA file is of an unsupported type: {header.ImageType}.");
}
var bytesPerPixel = header.ImagePixelSize / 8;
byte[] data;
switch (header.ImageType)
{
case TgaImageType.UncompressedRgb:
case TgaImageType.UncompressedBlackAndWhite:
data = reader.ReadBytes(header.Width * header.Height * bytesPerPixel);
break;
case TgaImageType.RunLengthEncodedRgb:
data = ReadRunLengthEncodedRgbData(reader, header, bytesPerPixel);
break;
default:
throw new InvalidOperationException();
}
var stride = header.Width * bytesPerPixel;
// Invert y, because data is stored bottom-up in TGA.
var invertedData = new byte[data.Length];
var invertedY = 0;
for (var y = header.Height - 1; y >= 0; y--)
{
Array.Copy(
data,
y * stride,
invertedData,
invertedY * stride,
stride);
invertedY++;
}
return(new TgaFile
{
Header = header,
Data = invertedData
});
}
}
