/// <summary>
/// Reads DDS formatted data from a stream. Image data is always returned as DXGI-Compliant
/// format, therefore some old legacy formats will automatically be converted.
/// </summary>
/// <param name="input">Input stream.</param>
/// <param name="flags">Flags to control how the DDS data is loaded.</param>
/// <returns>Loaded image data, or null if the data failed to load.</returns>
public static DDSContainer Read(Stream input, DDSFlags flags = DDSFlags.None)
{
StreamTransferBuffer buffer = new StreamTransferBuffer();
Header header;
Header10?headerExt;
//Reads + validates header(s)
if (!ReadHeader(input, buffer, out header, out headerExt))
{
return(null);
}
//Gather up metadata
List <MipChain> mipChains = null;
DXGIFormat format = DXGIFormat.Unknown;
TextureDimension texDim = TextureDimension.Two;
ConversionFlags convFlags = ConversionFlags.None;
bool legacyDword = (flags & DDSFlags.LegacyDword) == DDSFlags.LegacyDword ? true : false;
int width = Math.Max((int)header.Width, 1);
int height = Math.Max((int)header.Height, 1);
int depth = Math.Max((int)header.Depth, 1);
int mipCount = (int)header.MipMapCount;
int arrayCount = 1;
//Has extended header, a modern DDS
if (headerExt.HasValue)
{
Header10 extendedHeader = headerExt.Value;
arrayCount = (int)extendedHeader.ArraySize;
format = extendedHeader.Format;
switch (extendedHeader.ResourceDimension)
{
case D3D10ResourceDimension.Texture1D:
{
texDim = TextureDimension.One;
if (height > 1 || depth > 1)
{
return(null);
}
}
break;
case D3D10ResourceDimension.Texture2D:
{
if ((extendedHeader.MiscFlags & Header10Flags.TextureCube) == Header10Flags.TextureCube)
{
//Specifies # of cubemaps, so to get total # of faces must multiple by 6
arrayCount *= 6;
texDim = TextureDimension.Cube;
}
else
{
texDim = TextureDimension.Two;
}
if (depth > 1)
{
return(null);
}
}
break;
case D3D10ResourceDimension.Texture3D:
{
texDim = TextureDimension.Three;
if (arrayCount > 1 || (header.Caps2 & HeaderCaps2.Volume) != HeaderCaps2.Volume)
{
return(null);
}
}
break;
}
}
else
{
//Otherwise, read legacy DDS and possibly convert data
//Check volume flag
if ((header.Caps2 & HeaderCaps2.Volume) == HeaderCaps2.Volume)
{
texDim = TextureDimension.Three;
}
else
{
//legacy DDS could not express 1D textures, so either a cubemap or a 2D non-array texture
if ((header.Caps2 & HeaderCaps2.Cubemap) == HeaderCaps2.Cubemap)
{
//Must have all six faces. DirectX 8 and above always would write out all 6 faces
if ((header.Caps2 & HeaderCaps2.Cubemap_AllFaces) != HeaderCaps2.Cubemap_AllFaces)
{
return(null);
}
arrayCount = 6;
texDim = TextureDimension.Cube;
}
else
{
texDim = TextureDimension.Two;
}
}
format = FormatConverter.DetermineDXGIFormat(header.PixelFormat, flags, out convFlags);
}
//Modify conversion flags, if necessary
FormatConverter.ModifyConversionFormat(ref format, ref convFlags, flags);
//If palette image, the palette will be the first thing
int[] palette = null;
if (FormatConverter.HasConversionFlag(convFlags, ConversionFlags.Pal8))
{
palette = new int[256];
int palSize = palette.Length * sizeof(int);
buffer.ReadBytes(input, palSize);
if (buffer.LastReadByteCount != palSize)
{
return(null);
}
MemoryHelper.CopyBytes <int>(buffer.ByteArray, 0, palette, 0, palette.Length);
}
//Now read data based on available mip/arrays
mipChains = new List <MipChain>(arrayCount);
byte[] scanline = buffer.ByteArray;
IntPtr scanlinePtr = buffer.Pointer;
bool noPadding = (flags & DDSFlags.NoPadding) == DDSFlags.NoPadding ? true : false;
bool isCompressed = FormatConverter.IsCompressed(format);
bool errored = false;
try
{
//Iterate over each array face...
for (int i = 0; i < arrayCount; i++)
{
MipChain mipChain = new MipChain(mipCount);
mipChains.Add(mipChain);
//Iterate over each mip face...
for (int mipLevel = 0; mipLevel < mipCount; mipLevel++)
{
//Calculate mip dimensions
int mipWidth = width;
int mipHeight = height;
int mipDepth = depth;
ImageHelper.CalculateMipmapLevelDimensions(mipLevel, ref mipWidth, ref mipHeight, ref mipDepth);
//Compute pitch, based on MSDN programming guide which says PitchOrLinearSize is unreliable and to calculate based on format.
//"real" mip width/height is the given mip width/height for all non-compressed, compressed images it will be smaller since each block
//is a 4x4 region of pixels.
int realMipWidth, realMipHeight, dstRowPitch, dstSlicePitch, bytesPerPixel;
ImageHelper.ComputePitch(format, mipWidth, mipHeight, out dstRowPitch, out dstSlicePitch, out realMipWidth, out realMipHeight, out bytesPerPixel, legacyDword);
int srcRowPitch = dstRowPitch;
int srcSlicePitch = dstSlicePitch;
//Are we converting from a legacy format, possibly?
if (!headerExt.HasValue)
{
int legacySize = FormatConverter.LegacyFormatBitsPerPixelFromConversionFlag(convFlags);
if (legacySize != 0)
{
srcRowPitch = (realMipWidth * legacySize + 7) / 8;
srcSlicePitch = srcRowPitch * realMipHeight;
}
}
//If output data is requested not to have padding, recompute destination pitches
if (noPadding)
{
dstRowPitch = bytesPerPixel * realMipWidth;
dstSlicePitch = dstRowPitch * realMipHeight;
}
//Setup memory to hold the loaded image
MipData mipSurface = new MipData(mipWidth, mipHeight, mipDepth, dstRowPitch, dstSlicePitch);
mipChain.Add(mipSurface);
//Ensure read buffer is sufficiently sized for a single scanline
if (buffer.Length < srcRowPitch)
{
buffer.Resize(srcRowPitch, false);
}
IntPtr dstPtr = mipSurface.Data;
//Advance stream one slice at a time...
for (int slice = 0; slice < mipDepth; slice++)
{
long slicePos = input.Position;
IntPtr dPtr = dstPtr;
//Copy scanline into temp buffer, do any conversions, copy to output
for (int row = 0; row < realMipHeight; row++)
{
int numBytesRead = input.Read(scanline, 0, srcRowPitch);
if (numBytesRead != srcRowPitch)
{
errored = true;
System.Diagnostics.Debug.Assert(false);
return(null);
}
//Copy scanline, optionally convert data
FormatConverter.CopyScanline(dPtr, dstRowPitch, scanlinePtr, srcRowPitch, format, convFlags, palette);
//Increment dest pointer to next row
dPtr = MemoryHelper.AddIntPtr(dPtr, dstRowPitch);
}
//Advance stream and destination pointer to the next slice
input.Position = slicePos + srcSlicePitch;
dstPtr = MemoryHelper.AddIntPtr(dstPtr, dstSlicePitch);
}
}
}
}
finally
{
//If errored, clean up any mip surfaces we allocated...no null entries should have been made either
if (errored)
{
DisposeMipChains(mipChains);
}
}
if (!ValidateInternal(mipChains, format, texDim))
{
System.Diagnostics.Debug.Assert(false);
return(null);
}
return(new DDSContainer(mipChains, format, texDim));
}