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C64: Don't reallocate the SID filter buffer every time (purely perf)

This commit is contained in:
SaxxonPike 2019-07-19 19:09:08 -05:00
parent a119420c79
commit 1e5fe55f30
1 changed files with 14 additions and 11 deletions
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25
BizHawk.Emulation.Cores/Computers/Commodore64/MOS/Sid.cs
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@ -61,7 +61,8 @@ namespace BizHawk.Emulation.Cores.Computers.Commodore64.MOS
public Func<int> ReadPotX;
public Func<int> ReadPotY;
public RealFFT fft;
private RealFFT _fft;
private double[] _fftBuffer = new double[0];
private readonly int _cpuCyclesNum;
private int _sampleCyclesNum;
@ -260,18 +261,20 @@ namespace BizHawk.Emulation.Cores.Computers.Commodore64.MOS
}
}
fft = new RealFFT(nsamp_2);
_fft = new RealFFT(nsamp_2);
double[] temp_buffer = new double[nsamp_2];
// eventually this will settle on a single buffer size and stop reallocating
if (_fftBuffer.Length < nsamp_2)
Array.Resize(ref _fftBuffer, nsamp_2);
// linearly interpolate the original sample set into the new denser sample set
for (double i = 0; i < nsamp_2; i++)
{
temp_buffer[(int)i] = _outputBufferFiltered[(int)Math.Floor((i / (nsamp_2-1) * (nsamp - 1))) + _filterIndex];
_fftBuffer[(int)i] = _outputBufferFiltered[(int)Math.Floor((i / (nsamp_2-1) * (nsamp - 1))) + _filterIndex];
}
// now we have everything we need to perform the FFT
fft.ComputeForward(temp_buffer);
_fft.ComputeForward(_fftBuffer);
// for each element in the frequency list, attenuate it according to the specs
for (int i = 1; i < nsamp_2; i++)
@ -282,7 +285,7 @@ namespace BizHawk.Emulation.Cores.Computers.Commodore64.MOS
// let's assume that frequencies near the peak are doubled in strength at max resonance
if ((1.2 > freq / loc_filterFrequency) && (freq / loc_filterFrequency > 0.8 ))
{
temp_buffer[i] = temp_buffer[i] * (1 + (double)_filterResonance/15);
_fftBuffer[i] = _fftBuffer[i] * (1 + (double)_filterResonance/15);
}
// low pass filter
@ -291,7 +294,7 @@ namespace BizHawk.Emulation.Cores.Computers.Commodore64.MOS
//attenuated at 12db per octave
attenuation = Math.Log(freq / loc_filterFrequency, 2);
attenuation = 12 * attenuation;
temp_buffer[i] = temp_buffer[i] * Math.Pow(2, -attenuation / 10);
_fftBuffer[i] = _fftBuffer[i] * Math.Pow(2, -attenuation / 10);
}
// High pass filter
@ -300,7 +303,7 @@ namespace BizHawk.Emulation.Cores.Computers.Commodore64.MOS
//attenuated at 12db per octave
attenuation = Math.Log(loc_filterFrequency / freq, 2);
attenuation = 12 * attenuation;
temp_buffer[i] = temp_buffer[i] * Math.Pow(2, -attenuation / 10);
_fftBuffer[i] = _fftBuffer[i] * Math.Pow(2, -attenuation / 10);
}
// Band pass filter
@ -309,19 +312,19 @@ namespace BizHawk.Emulation.Cores.Computers.Commodore64.MOS
//attenuated at 6db per octave
attenuation = Math.Log(freq / loc_filterFrequency, 2);
attenuation = 6 * attenuation;
temp_buffer[i] = temp_buffer[i] * Math.Pow(2, -Math.Abs(attenuation) / 10);
_fftBuffer[i] = _fftBuffer[i] * Math.Pow(2, -Math.Abs(attenuation) / 10);
}
}
// now transform back into time space and reassemble the attenuated frequency components
fft.ComputeReverse(temp_buffer);
_fft.ComputeReverse(_fftBuffer);
int temp = nsamp - 1;
//re-sample back down to the original number of samples
for (double i = 0; i < nsamp; i++)
{
_outputBufferFiltered[(int)i + _filterIndex] = (int)(temp_buffer[(int)Math.Ceiling((i / (nsamp - 1) * (nsamp_2 - 1)))]/(nsamp_2/2));
_outputBufferFiltered[(int)i + _filterIndex] = (int)(_fftBuffer[(int)Math.Ceiling((i / (nsamp - 1) * (nsamp_2 - 1)))]/(nsamp_2/2));
if (_outputBufferFiltered[(int)i + _filterIndex] < 0)
{