public static void SetResonantLowpass2Coefficients(
ResonantLowpass2Rec Filter,
double Cutoff,
double Q,
double SamplingRate)
{
if ((Cutoff == Filter.OldCutoff) && (Q == Filter.OldQ))
{
return;
}
Filter.OldCutoff = Cutoff;
Filter.OldQ = Q;
ComputeResonantLowpass2Coefficients(
ref Filter.iir0,
ref Filter.iir1,
ref Filter.iir2,
Filter.Order,
Cutoff,
Q,
SamplingRate);
}
/* apply filter to an array of values, adding result to output array */
public void Apply(
float[] XinVector,
int XinVectorOffset,
float[] YoutVector,
int YoutVectorOffset,
int VectorLength,
float OutputScaling,
SynthParamRec SynthParams)
{
ResonantLowpass2Rec Filter = this;
// ScratchWorkspace1* is used in ApplyUnifiedFilterArray()
#if DEBUG
Debug.Assert(!SynthParams.ScratchWorkspace2InUse);
SynthParams.ScratchWorkspace2InUse = true;
#endif
float[] ScratchVector = XinVector /*sic*/;
int ScratchVectorOffset = SynthParams.ScratchWorkspace2LOffset;
int Order2 = Filter.Order / 2;
if (Order2 == 1)
{
IIR2DirectIIMAcc(
ref Filter.iir0,
XinVector,
XinVectorOffset,
YoutVector,
YoutVectorOffset,
VectorLength,
OutputScaling);
}
else
{
// In the old code there was a bad bug where the last biquad section was applied
// from the original input to the output, causing all the intermediate results
// from previous biquads to be disregarded. Naturally, this causes a very different
// sound, which has already been used. Therefore, there is an option to enable
// the old behavior.
if (!Filter.broken)
{
// The correct implementation
if (Order2 == 2)
{
/* first section enters local workspace */
IIR2DirectII(
ref Filter.iir0,
XinVector,
XinVectorOffset,
ScratchVector,
ScratchVectorOffset,
VectorLength);
/* final section goes into output */
IIR2DirectIIMAcc(
ref Filter.iir1,
ScratchVector, // NB: in defective version this was XinVector
ScratchVectorOffset,
YoutVector,
YoutVectorOffset,
VectorLength,
OutputScaling);
}
else
{
#if DEBUG
Debug.Assert(Order2 == 3);
#endif
/* first section enters local workspace */
IIR2DirectII(
ref Filter.iir0,
XinVector,
XinVectorOffset,
ScratchVector,
ScratchVectorOffset,
VectorLength);
/* intermediate sections */
IIR2DirectII(
ref Filter.iir1,
ScratchVector,
ScratchVectorOffset,
ScratchVector,
ScratchVectorOffset,
VectorLength);
/* final section goes into output */
IIR2DirectIIMAcc(
ref Filter.iir2,
ScratchVector, // NB: in defective version this was XinVector
ScratchVectorOffset,
YoutVector,
YoutVectorOffset,
VectorLength,
OutputScaling);
}
}
else
{
// The old broken buggy defective implementation
if (Order2 == 2)
{
/* final section goes into output */
IIR2DirectIIMAcc(
ref Filter.iir1,
XinVector, // this should have been Workspace
XinVectorOffset,
YoutVector,
YoutVectorOffset,
VectorLength,
OutputScaling);
}
else
{
#if DEBUG
Debug.Assert(Order2 == 3);
#endif
/* final section goes into output */
IIR2DirectIIMAcc(
ref Filter.iir2,
XinVector, // this should have been Workspace
XinVectorOffset,
YoutVector,
YoutVectorOffset,
VectorLength,
OutputScaling);
}
}
}
#if DEBUG
SynthParams.ScratchWorkspace2InUse = false;
#endif
}
