public ClusterFit(ColourSet colours, SquishFlags flags, float?metric)
: base(colours, flags)
{
// set the iteration count
_mIterationCount = (MFlags & SquishFlags.KColourIterativeClusterFit) != 0 ? 8 : 1;
// initialise the metric (old perceptual = 0.2126f, 0.7152f, 0.0722f)
if (metric != null)
{
//m_metric = Vec4( metric[0], metric[1], metric[2], 1.0f );
}
else
{
_mMetric = new Vector4(1.0f);
}
// initialise the best error
_mBesterror = new Vector4(float.MaxValue);
// cache some values
var count = MColours.Count;
var values = MColours.Points;
// get the covariance matrix
var covariance = Sym3X3.ComputeWeightedCovariance(count, values, MColours.Weights);
// compute the principle component
_mPrinciple = Sym3X3.ComputePrincipleComponent(covariance);
}
public SingleColourFit(ColourSet colours, SquishFlags flags)
: base(colours, flags)
{
// grab the single colour
var values = MColours.Points;
_mColour[0] = (byte)ColourBlock.FloatToInt(255.0f * values[0].X, 255);
_mColour[1] = (byte)ColourBlock.FloatToInt(255.0f * values[0].Y, 255);
_mColour[2] = (byte)ColourBlock.FloatToInt(255.0f * values[0].Z, 255);
// initialise the best error
_mBesterror = int.MaxValue;
}
private static void CompressMasked(byte[] rgba, int mask, ref byte[] block, int offset, SquishFlags flags, float?metric)
{
// fix any bad flags
flags = FixFlags(flags);
// get the block locations
var colourBlock = offset;
var alphaBlock = offset;
if ((flags & (SquishFlags.KDxt3 | SquishFlags.KDxt5)) != 0)
{
colourBlock += 8;
}
// create the minimal point set
var colours = new ColourSet(rgba, mask, flags);
// check the compression type and compress colour
if (colours.Count == 1)
{
// always do a single colour fit
var fit = new SingleColourFit(colours, flags);
fit.Compress(ref block, colourBlock);
}
else if ((flags & SquishFlags.KColourRangeFit) != 0 || colours.Count == 0)
{
// do a range fit
var fit = new RangeFit(colours, flags, metric);
fit.Compress(ref block, colourBlock);
}
else
{
// default to a cluster fit (could be iterative or not)
var fit = new ClusterFit(colours, flags, metric);
fit.Compress(ref block, colourBlock);
}
// compress alpha separately if necessary
if ((flags & SquishFlags.KDxt3) != 0)
{
CompressAlphaDxt3(rgba, mask, ref block, alphaBlock);
}
else if ((flags & SquishFlags.KDxt5) != 0)
{
CompressAlphaDxt5(rgba, mask, ref block, alphaBlock);
}
}
public RangeFit(ColourSet colours, SquishFlags flags, float?metric)
: base(colours, flags)
{
// initialise the metric (old perceptual = 0.2126f, 0.7152f, 0.0722f)
if (metric != null)
{
//m_metric = new Vector3( metric[0], metric[1], metric[2] );
}
else
{
_mMetric = new Vector3(1.0f);
}
// initialise the best error
_mBesterror = float.MaxValue;
// cache some values
var count = MColours.Count;
var values = MColours.Points;
var weights = MColours.Weights;
// get the covariance matrix
var covariance = Sym3X3.ComputeWeightedCovariance(count, values, weights);
// compute the principle component
var principle = Sym3X3.ComputePrincipleComponent(covariance);
// get the min and max range as the codebook endpoints
var start = new Vector3(0.0f);
var end = new Vector3(0.0f);
if (count > 0)
{
float max;
// compute the range
start = end = values[0];
var min = max = Vector3.Dot(values[0], principle);
for (var i = 1; i < count; ++i)
{
var val = Vector3.Dot(values[i], principle);
if (val < min)
{
start = values[i];
min = val;
}
else if (val > max)
{
end = values[i];
max = val;
}
}
}
// clamp the output to [0, 1]
var one = new Vector3(1.0f);
var zero = new Vector3(0.0f);
start = Vector3.Min(one, Vector3.Max(zero, start));
end = Vector3.Min(one, Vector3.Max(zero, end));
// clamp to the grid and save
var grid = new Vector3(31.0f, 63.0f, 31.0f);
var gridrcp = new Vector3(1.0f / 31.0f, 1.0f / 63.0f, 1.0f / 31.0f);
var half = new Vector3(0.5f);
_mStart = Helpers.Truncate(grid * start + half) * gridrcp;
_mEnd = Helpers.Truncate(grid * end + half) * gridrcp;
}