public static byte PerformLookup(byte value)
{
if (_lookupTable is null)
{
CalculateLookups();
}
// Can safely cast to byte, cause of the constrain of 255
return((byte)ScalingUtils.ConstrainNonnegative(_lookupTable[value], 255));
}
private static void CalculateLookups()
{
var lut = new short[OutputRange + 1];
const double coefficientA = -CoefficientB;
var coefficientC = Math.Log((OutputRange - coefficientA) / CoefficientB) / OutputRange;
for (var i = 0; i < OutputRange + 1; i++)
{
lut[i] = (short)Math.Ceiling(coefficientA + CoefficientB * Math.Exp(coefficientC * i));
lut[i] = ScalingUtils.ConstrainNonnegative(lut[i], OutputRange);
}
_lookupTable = lut;
}