private static unsafe MipGeneratorFn _Get(MipFormat format)
{
switch (format)
{
case MipFormat.RGBA:
case MipFormat.pRGBA:
return(_Color);
// FIXME: Is this right? I think maybe it needs to be different
case MipFormat.RGBA | MipFormat.sRGB:
case MipFormat.pRGBA | MipFormat.sRGB:
return(_sRGBColor);
case MipFormat.Gray1:
return(_Gray);
case MipFormat.pGray4:
return(_PAGray);
case MipFormat.pGray4 | MipFormat.sRGB:
return(_sRGBPAGray);
default:
return(null);
}
}
public unsafe MipGeneratorFn Get(MipFormat format)
{
switch (format)
{
case MipFormat.pGray4:
return(PAGray);
default:
throw new ArgumentOutOfRangeException("format");
}
}
public static unsafe MipGeneratorFn Get(
MipFormat format,
stbir_filter filter_horizontal = stbir_filter.DEFAULT,
stbir_filter filter_vertical = stbir_filter.DEFAULT,
stbir_edge edge_horizontal = stbir_edge.CLAMP,
stbir_edge edge_vertical = stbir_edge.CLAMP
)
{
var masked = (format & ~MipFormat.sRGB);
var datatype = (masked == MipFormat.Vector4) ||
(masked == MipFormat.pVector4) ||
(masked == MipFormat.Single)
? stbir_datatype.FLOAT
: stbir_datatype.UINT8;
var colorspace = (format & MipFormat.sRGB) == MipFormat.sRGB
? stbir_colorspace.SRGB
: stbir_colorspace.LINEAR;
var channels = masked == MipFormat.Gray1 ? 1 : 4;
var flags = (masked == MipFormat.pRGBA) ||
(masked == MipFormat.pGray4) ||
(masked == MipFormat.pVector4)
? stbir_flags.ALPHA_PREMULTIPLIED
: default;
var alpha_channel = (masked == MipFormat.Gray1) ? -1 : 3;
unsafe void Implementation(
void *src, int srcWidth, int srcHeight, int srcStrideBytes,
void *dest, int destWidth, int destHeight, int destStrideBytes
)
{
var result = API.stbir_resize(
src, srcWidth, srcHeight, srcStrideBytes,
dest, destWidth, destHeight, destStrideBytes,
datatype, channels, alpha_channel, (int)flags,
edge_horizontal, edge_vertical,
filter_horizontal, filter_vertical,
colorspace, null
);
if (result != 1)
{
throw new Exception("An error occurred in stb_image_resize");
}
}
return(Implementation);
}
}
public static MipGeneratorFn Get(MipFormat format)
{
var index = (int)format;
if ((index < 0) || (index >= Cache.Length))
{
throw new ArgumentOutOfRangeException("format");
}
var result = Cache[index];
if (result == null)
{
throw new ArgumentOutOfRangeException("format");
}
return(result);
}
public static void Set(MipFormat format, MipGeneratorFn implementation)
{
Cache[(int)format] = implementation;
}
private unsafe void GenerateMips(bool sRGB)
{
void *pPreviousLevelData = null, pLevelData = Data;
int levelWidth = Width, levelHeight = Height;
int previousLevelWidth = Width, previousLevelHeight = Height;
// FIXME
MipChain = new byte[64][];
var pins = new List <GCHandle>();
MipFormat format = (MipFormat)(-1);
if (IsFloatingPoint)
{
if (ChannelCount == 4)
{
format = IsPremultiplied ? MipFormat.pVector4 : MipFormat.Vector4;
}
else if (ChannelCount == 1)
{
format = MipFormat.Single;
}
}
else if (!Is16Bit)
{
if (ChannelCount == 4)
{
format = IsPremultiplied ? MipFormat.pRGBA : MipFormat.RGBA;
}
else
{
format = MipFormat.Gray1;
}
}
if (format == (MipFormat)(-1))
{
throw new ArgumentOutOfRangeException("Mip generation is not supported for this image format");
}
if (sRGB)
{
format |= MipFormat.sRGB;
}
var mipGenerator = STBMipGenerator.Get(format);
for (uint level = 0; (levelWidth >= 1) && (levelHeight >= 1); level++)
{
if (IsDisposed)
{
throw new ObjectDisposedException("Image");
}
if (level > 0)
{
var levelBuf = new byte[levelWidth * levelHeight * SizeofPixel];
MipChain[level - 1] = levelBuf;
var pin = GCHandle.Alloc(levelBuf, GCHandleType.Pinned);
pins.Add(pin);
pLevelData = (void *)pin.AddrOfPinnedObject();
// FIXME: Do this one step at a time in a list of work items
var previousStrideBytes = previousLevelWidth * SizeofPixel;
var levelStrideBytes = levelWidth * SizeofPixel;
mipGenerator(
pPreviousLevelData, previousLevelWidth, previousLevelHeight, previousStrideBytes,
pLevelData, levelWidth, levelHeight, levelStrideBytes
);
}
previousLevelWidth = levelWidth;
previousLevelHeight = levelHeight;
var newWidth = levelWidth / 2;
var newHeight = levelHeight / 2;
levelWidth = newWidth;
levelHeight = newHeight;
pPreviousLevelData = pLevelData;
}
foreach (var pin in pins)
{
pin.Free();
}
}
