/** Evaluates the LegendrePolynomial for L,M at X */
FORCEINLINE FLOAT LegendrePolynomial(INT L,INT M,FLOAT X)
{
switch(L)
{
case 0:
return 1;
case 1:
if(M == 0)
return X;
else if(M == 1)
return -SafeSqrt(1 - X * X);
break;
case 2:
if(M == 0)
return -0.5f + (3 * X * X) / 2;
else if(M == 1)
return -3 * X * SafeSqrt(1 - X * X);
else if(M == 2)
return -3 * (-1 + X * X);
break;
case 3:
if(M == 0)
return -(3 * X) / 2 + (5 * X * X * X) / 2;
else if(M == 1)
return -3 * SafeSqrt(1 - X * X) / 2 * (-1 + 5 * X * X);
else if(M == 2)
return -15 * (-X + X * X * X);
else if(M == 3)
return -15 * appPow(1 - X * X,1.5f);
break;
case 4:
if(M == 0)
return 0.125f * (3.0f - 30.0f * X * X + 35.0f * X * X * X * X);
else if(M == 1)
return -2.5f * X * SafeSqrt(1.0f - X * X) * (7.0f * X * X - 3.0f);
else if(M == 2)
return -7.5f * (1.0f - 8.0f * X * X + 7.0f * X * X * X * X);
else if(M == 3)
return -105.0f * X * appPow(1 - X * X,1.5f);
else if(M == 4)
return 105.0f * Square(X * X - 1.0f);
break;
case 5:
if(M == 0)
return 0.125f * X * (15.0f - 70.0f * X * X + 63.0f * X * X * X * X);
else if(M == 1)
return -1.875f * SafeSqrt(1.0f - X * X) * (1.0f - 14.0f * X * X + 21.0f * X * X * X * X);
else if(M == 2)
return -52.5f * (X - 4.0f * X * X * X + 3.0f * X * X * X * X * X);
else if(M == 3)
return -52.5f * appPow(1.0f - X * X,1.5f) * (9.0f * X * X - 1.0f);
else if(M == 4)
return 945.0f * X * Square(X * X - 1);
else if(M == 5)
return -945.0f * appPow(1.0f - X * X,2.5f);
break;
};
return 0.0f;
}
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// RadioEffectUnit::RadioEffectKernel::Process
//
// pass-through unit
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
void RadioEffectUnit::RadioEffectKernel::Process( const AudioUnitSampleType * InSourceP,
AudioUnitSampleType * InDestP,
UInt32 InFramesToProcess,
UInt32 InNumChannels,
bool & IOSilence )
{
// we should be doing something with the silence flag if it is true
// like not doing any work because:
// (1) we would only be processing silence and
// (2) we don't have any latency or tail times to worry about here
//
// So, we don't reset this flag, because it is true on input and we're not doing anything
// to it so we want it to be true on output.
// BUT: your code probably will need to take into account tail processing (or latency) that
// it has once its input becomes silent... then at some point in the future, your output
// will also be silent.
UInt32 NumSampleFrames = InFramesToProcess;
const AudioUnitSampleType *SourceP = InSourceP;
AudioUnitSampleType *DestP = InDestP;
const FLOAT ChebyshevPowerMultiplier = GetParameter(RadioParam_ChebyshevPowerMultiplier);
const FLOAT ChebyshevPower = GetParameter(RadioParam_ChebyshevPower);
const FLOAT ChebyshevCubedMultiplier = GetParameter(RadioParam_ChebyshevCubedMultiplier);
const FLOAT ChebyshevMultiplier = GetParameter(RadioParam_ChebyshevMultiplier);
while (NumSampleFrames-- > 0) {
AudioUnitSampleType InputSample = *SourceP;
SourceP += InNumChannels; // advance to next frame (e.g. if stereo, we're advancing 2 samples);
// we're only processing one of an arbitrary number of interleaved channels
// here's where you do your DSP work
// Early-out of processing if the sample is zero because a zero sample
// will still create some static even if no audio is playing.
if( InputSample != 0.0f ) {
// Waveshape it
const FLOAT SampleCubed = InputSample * InputSample * InputSample;
InputSample = ( ChebyshevPowerMultiplier * appPow( InputSample, ChebyshevPower ) ) - ( ChebyshevCubedMultiplier * SampleCubed ) + ( ChebyshevMultiplier * InputSample );
// Again with the bandpass
InputSample = GFinalBandPassFilter.Process( InputSample );
}
*DestP = InputSample;
DestP += InNumChannels;
}
}
