public override float Interpolate(float theBlend)
{
switch (mode)
{
case CCInterpolationMode.IN:
return((theBlend == 0) ? 0 : theBlend *CCMath.Pow(2, 10 *(theBlend - 1)));
case CCInterpolationMode.OUT:
return((theBlend == 1) ? 1 : (-CCMath.Pow(2, -10 * theBlend) + 1));
}
if ((theBlend) < 0.5)
{
return(0.5f * CCMath.Pow(2, 10 * (theBlend - 1)));
}
return(0.5f * (-CCMath.Pow(2, -10 * (theBlend - 1)) + 2));
}
public override float Interpolate(float theBlend)
{
switch (mode)
{
case CCInterpolationMode.IN:
return(CCMath.Pow(theBlend, pow));
case CCInterpolationMode.OUT:
return(1 - CCMath.Pow(1 - theBlend, pow));
}
if (theBlend < 0.5f)
{
return(CCMath.Pow(theBlend * 2, pow) / 2);
}
return(1 - CCMath.Pow((1 - theBlend) * 2, pow) / 2);
}
protected internal override void CalcCoeff()
{
calcpoles();
// System.out.println("ChebFilter is calculating coefficients...");
// initialize our arrays
for (int i = 0; i < 23; ++i)
{
ca[i] = cb[i] = ta[i] = tb[i] = 0.0f;
}
// I don't know why this must be done
ca[2] = 1.0f;
cb[2] = 1.0f;
// calculate two poles at a time
for (int p = 1; p <= poles / 2; p++)
{
// calc pair p, put the results in pa and pb
calcTwoPole(p, pa, pb);
// copy ca and cb into ta and tb
Array.Copy(ca, 0, ta, 0, ta.Length);
Array.Copy(cb, 0, tb, 0, tb.Length);
// add coefficients to the cascade
for (int i = 2; i < 23; i++)
{
ca[i] = pa[0] * ta[i] + pa[1] * ta[i - 1] + pa[2] * ta[i - 2];
cb[i] = tb[i] - pb[0] * tb[i - 1] - pb[1] * tb[i - 2];
}
}
// final stage of combining coefficients
cb[2] = 0;
for (int i = 0; i < 21; i++)
{
ca[i] = ca[i + 2];
cb[i] = -cb[i + 2];
}
// normalize the gain
float sa = 0;
float sb = 0;
for (int i = 0; i < 21; i++)
{
if (type == ChebFilterType.LP)
{
sa += ca[i];
sb += cb[i];
}
else
{
sa += ca[i] * CCMath.Pow(-1, i);
sb += cb[i] * CCMath.Pow(-1, i);
}
}
float gain = sa / (1 - sb);
for (int i = 0; i < 21; i++)
{
ca[i] /= gain;
}
// initialize the coefficient arrays used by process()
// but only if the number of poles has changed
if (a == null || a.Length != poles + 1)
{
a = new float[poles + 1];
}
if (b == null || b.Length != poles)
{
b = new float[poles];
}
// copy the values from ca and cb into a and b
// in this implementation cb[0] = 0 and cb[1] is where
// the b coefficients begin, so they are numbered the way
// one normally numbers coefficients when talking about IIR filters
// however, process() expects b[0] to be the coefficient B1
// so we copy cb over to b starting at index 1
Array.Copy(ca, 0, a, 0, a.Length);
Array.Copy(cb, 1, b, 0, b.Length);
}
