public static ColorBlock Fit(ColorSet colors, Options options, bool isBC1)
{
int count = colors.Count;
Vector3[] points = colors.Points;
double[] weights = colors.Weights;
// compute the principle component
Vector3 principle = ComputePrincipleComponent(count, points, weights);
// get the min and max range as the codebook endpoints
Vector3 start = new Vector3();
Vector3 end = new Vector3();
if( count > 0 )
{
double min, max;
// compute the range
start = end = points[0];
min = max = Vector3.Dot(points[0], principle);
for( int i = 1; i < count; ++i )
{
double val = Vector3.Dot(points[i], principle);
if( val < min )
{
start = points[i];
min = val;
}
else if( val > max )
{
end = points[i];
max = val;
}
}
}
// clamp the output to [0, 1]
start = Vector3.Clamp(start, 0.0, 1.0);
end = Vector3.Clamp(end, 0.0, 1.0);
// clamp to the grid and save
Vector3 grid = new Vector3(31.0, 63.0, 31.0);
Vector3 gridrcp = Vector3.Reciprocal(grid);
Vector3 half = new Vector3(0.5);
start = Truncate(grid * start + half) * gridrcp;
end = Truncate(grid * end + half) * gridrcp;
// create a codebook
Vector3[] codes = new Vector3[4];
codes[0] = start;
codes[1] = end;
codes[2] = (2.0 / 3.0) * start + (1.0 / 3.0) * end;
codes[3] = (1.0 / 3.0) * start + (2.0 / 3.0) * end;
// match each point to the closest code
int[] closest = new int[16];
double error = 0.0f;
for( int i = 0; i < count; ++i )
{
// find the closest code
double dist = double.MaxValue;
int idx = 0;
for( int j = 0; j < 4; ++j )
{
double d = (options.Metric * (points[i] - codes[j])).MagnitudeSquared;
if( d < dist )
{
dist = d;
idx = j;
}
}
// save the index
closest[i] = idx;
// accumulate the error
error += dist;
}
// remap the indices
int[] indices = new int[16];
colors.RemapIndices(closest, indices);
return new ColorBlock(new Color(start.X, start.Y, start.Z), new Color(end.X, end.Y, end.Z), indices);
}
public static ColorBlock Fit(ColorSet colors, Options options, bool isBC1)
{
int count = colors.Count;
Vector3[] points = colors.Points;
double[] weights = colors.Weights;
// compute the principle component
Vector3 principle = ComputePrincipleComponent(count, points, weights);
// get the min and max range as the codebook endpoints
Vector3 start = new Vector3();
Vector3 end = new Vector3();
if (count > 0)
{
double min, max;
// compute the range
start = end = points[0];
min = max = Vector3.Dot(points[0], principle);
for (int i = 1; i < count; ++i)
{
double val = Vector3.Dot(points[i], principle);
if (val < min)
{
start = points[i];
min = val;
}
else if (val > max)
{
end = points[i];
max = val;
}
}
}
// clamp the output to [0, 1]
start = Vector3.Clamp(start, 0.0, 1.0);
end = Vector3.Clamp(end, 0.0, 1.0);
// clamp to the grid and save
Vector3 grid = new Vector3(31.0, 63.0, 31.0);
Vector3 gridrcp = Vector3.Reciprocal(grid);
Vector3 half = new Vector3(0.5);
start = Truncate(grid * start + half) * gridrcp;
end = Truncate(grid * end + half) * gridrcp;
// create a codebook
Vector3[] codes = new Vector3[4];
codes[0] = start;
codes[1] = end;
codes[2] = (2.0 / 3.0) * start + (1.0 / 3.0) * end;
codes[3] = (1.0 / 3.0) * start + (2.0 / 3.0) * end;
// match each point to the closest code
int[] closest = new int[16];
double error = 0.0f;
for (int i = 0; i < count; ++i)
{
// find the closest code
double dist = double.MaxValue;
int idx = 0;
for (int j = 0; j < 4; ++j)
{
double d = (options.Metric * (points[i] - codes[j])).MagnitudeSquared;
if (d < dist)
{
dist = d;
idx = j;
}
}
// save the index
closest[i] = idx;
// accumulate the error
error += dist;
}
// remap the indices
int[] indices = new int[16];
colors.RemapIndices(closest, indices);
return(new ColorBlock(new Color(start.X, start.Y, start.Z), new Color(end.X, end.Y, end.Z), indices));
}