/// <summary>
/// KtxHeader constructor
/// </summary>
/// <param name="stream">Stream for reading</param>
public KtxHeader(Stream stream)
{
// Skip first 12 bytes since they only contain identifier
stream.Seek(12, SeekOrigin.Begin);
// Read endianness as bytes
byte[] endiannessBytes = new byte[4];
int bytesRead = stream.Read(buffer: endiannessBytes, offset: 0, count: endiannessBytes.Length);
if (bytesRead != 4)
{
throw new InvalidOperationException("Cannot read enough bytes from stream!");
}
if (!Common.littleEndianAsBytes.SequenceEqual(endiannessBytes) && !Common.bigEndianAsBytes.SequenceEqual(endiannessBytes))
{
throw new InvalidOperationException("Endianness info in header is not valid!");
}
this.isInputLittleEndian = Common.littleEndianAsBytes.SequenceEqual(endiannessBytes);
// Turn endianness as bytes to uint
this.endiannessValue = BitConverter.ToUInt32(endiannessBytes, 0);
// See if following uint reads need endian swap
bool shouldSwapEndianness = (this.endiannessValue != Common.expectedEndianValue);
// Use the stream in a binary reader.
using (BinaryReader reader = new BinaryReader(stream, Encoding.UTF8, leaveOpen: true))
{
// Swap endianness for every KTX variable if needed
this.glTypeAsUint = shouldSwapEndianness ? KtxBitFiddling.SwapEndian(reader.ReadUInt32()) : reader.ReadUInt32();
if (GlDataType.IsDefined(typeof(GlDataType), this.glTypeAsUint))
{
this.glDataType = (GlDataType)this.glTypeAsUint;
}
else
{
this.glDataType = GlDataType.NotKnown;
}
this.glTypeSizeAsUint = shouldSwapEndianness ? KtxBitFiddling.SwapEndian(reader.ReadUInt32()) : reader.ReadUInt32();
this.glFormatAsUint = shouldSwapEndianness ? KtxBitFiddling.SwapEndian(reader.ReadUInt32()) : reader.ReadUInt32();
if (GlPixelFormat.IsDefined(typeof(GlPixelFormat), this.glFormatAsUint))
{
this.glFormat = (GlPixelFormat)this.glFormatAsUint;
}
else
{
this.glFormat = GlPixelFormat.NotKnown;
}
this.glInternalFormatAsUint = shouldSwapEndianness ? KtxBitFiddling.SwapEndian(reader.ReadUInt32()) : reader.ReadUInt32();
if (GlInternalFormat.IsDefined(typeof(GlInternalFormat), this.glInternalFormatAsUint))
{
this.glInternalFormat = (GlInternalFormat)this.glInternalFormatAsUint;
}
else
{
this.glInternalFormat = GlInternalFormat.NotKnown;
}
this.glBaseInternalFormatAsUint = shouldSwapEndianness ? KtxBitFiddling.SwapEndian(reader.ReadUInt32()) : reader.ReadUInt32();
if (GlPixelFormat.IsDefined(typeof(GlPixelFormat), this.glBaseInternalFormatAsUint))
{
this.glPixelFormat = (GlPixelFormat)this.glBaseInternalFormatAsUint;
}
else
{
this.glPixelFormat = GlPixelFormat.NotKnown;
}
this.pixelWidth = shouldSwapEndianness ? KtxBitFiddling.SwapEndian(reader.ReadUInt32()) : reader.ReadUInt32();
this.pixelHeight = shouldSwapEndianness ? KtxBitFiddling.SwapEndian(reader.ReadUInt32()) : reader.ReadUInt32();
this.pixelDepth = shouldSwapEndianness ? KtxBitFiddling.SwapEndian(reader.ReadUInt32()) : reader.ReadUInt32();
this.numberOfArrayElements = shouldSwapEndianness ? KtxBitFiddling.SwapEndian(reader.ReadUInt32()) : reader.ReadUInt32();
this.numberOfFaces = shouldSwapEndianness ? KtxBitFiddling.SwapEndian(reader.ReadUInt32()) : reader.ReadUInt32();
this.numberOfMipmapLevels = shouldSwapEndianness ? KtxBitFiddling.SwapEndian(reader.ReadUInt32()) : reader.ReadUInt32();
this.bytesOfKeyValueData = shouldSwapEndianness ? KtxBitFiddling.SwapEndian(reader.ReadUInt32()) : reader.ReadUInt32();
// Check that bytesOfKeyValueData is mod 4
if (this.bytesOfKeyValueData % 4 != 0)
{
throw new InvalidOperationException(ErrorGen.Modulo4Error(nameof(this.bytesOfKeyValueData), this.bytesOfKeyValueData));
}
this.metadataDictionary = ParseMetadata(reader.ReadBytes((int)this.bytesOfKeyValueData), shouldSwapEndianness);
}
}
