/// <summary>
/// Reads a DDS header from a stream. On return, the stream will be positioned at the beginning of the texture data.
/// </summary>
/// <param name="stream">The stream to read from.</param>
/// <returns>The header that was read.</returns>
/// <exception cref="System.InvalidOperationException">Thrown if the DDS header is invalid.</exception>
public static DdsHeader Read(Stream stream)
{
var reader = new BinaryReader(stream);
if (stream.Length - stream.Position < 128)
{
throw new InvalidOperationException("Invalid DDS file: header is too small");
}
var result = new DdsHeader();
// Read and verify magic
if (reader.ReadUInt32() != DdsFourCc.FromString("DDS "))
{
throw new InvalidOperationException("Invalid DDS file: invalid header magic");
}
// Read the DDS header
result.ReadDdsHeader(reader);
// If the format FourCC is 'DX10', read the extended header
if (result.FourCc == DdsFourCc.FromString("DX10"))
{
result.ReadDdsD3D10Header(reader);
}
return(result);
}
private void WriteDdsPixelFormat(BinaryWriter writer)
{
writer.Write(32);
writer.Write((uint)CalculateFormatFlags());
writer.Write((D3D10Format == DxgiFormat.Unknown) ? FourCc : DdsFourCc.FromString("DX10"));
writer.Write(BitsPerPixel);
writer.Write(RBitMask);
writer.Write(GBitMask);
writer.Write(BBitMask);
writer.Write(ABitMask);
}
/// <summary>
/// Writes the DDS header to a stream. On return, the stream will be positioned where the texture data should go.
/// </summary>
/// <param name="stream">The stream to write to.</param>
/// <exception cref="System.InvalidOperationException">Thrown if an error occurs while saving.</exception>
public void WriteTo(Stream stream)
{
var writer = new BinaryWriter(stream);
writer.Write(DdsFourCc.FromString("DDS "));
WriteDdsHeader(writer);
if (D3D10Format != DxgiFormat.Unknown)
{
WriteDdsD3D10Header(writer);
}
}
