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Avoid manual loops for ALfilterState processing

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This commit is contained in:
Chris Robinson
2016-07-25 19:04:54 -07:00
parent 94dd34fb4b
commit e4bbbe06fa
1 changed files with 17 additions and 25 deletions
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Alc/effects/distortion.c
+17 -25
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@@ -97,7 +97,7 @@ static ALvoid ALdistortionState_process(ALdistortionState *state, ALuint Samples
for(base = 0;base < SamplesToDo;)
{
float oversample_buffer[64][4];
float buffer[2][64 * 4];
ALuint td = minu(64, SamplesToDo-base);
/* Perform 4x oversampling to avoid aliasing. */
@@ -109,10 +109,10 @@ static ALvoid ALdistortionState_process(ALdistortionState *state, ALuint Samples
/* Fill oversample buffer using zero stuffing */
for(it = 0;it < td;it++)
{
oversample_buffer[it][0] = SamplesIn[0][it+base];
oversample_buffer[it][1] = 0.0f;
oversample_buffer[it][2] = 0.0f;
oversample_buffer[it][3] = 0.0f;
buffer[0][it*4 + 0] = SamplesIn[0][it+base];
buffer[0][it*4 + 1] = 0.0f;
buffer[0][it*4 + 2] = 0.0f;
buffer[0][it*4 + 3] = 0.0f;
}
/* First step, do lowpass filtering of original signal, */
@@ -120,38 +120,30 @@ static ALvoid ALdistortionState_process(ALdistortionState *state, ALuint Samples
/* cutoff for oversampling (which is fortunately first */
/* step of distortion). So combine three operations into */
/* the one. */
ALfilterState_process(&state->lowpass, buffer[1], buffer[0], td*4);
/* Second step, do distortion using waveshaper function */
/* to emulate signal processing during tube overdriving. */
/* Three steps of waveshaping are intended to modify */
/* waveform without boost/clipping/attenuation process. */
for(it = 0;it < td;it++)
{
for(ot = 0;ot < 4;ot++)
{
ALfloat smp;
smp = ALfilterState_processSingle(&state->lowpass, oversample_buffer[it][ot]);
/* Restore signal power by multiplying sample by amount of oversampling */
oversample_buffer[it][ot] = smp * 4.0f;
}
}
for(it = 0;it < td;it++)
{
/* Second step, do distortion using waveshaper function */
/* to emulate signal processing during tube overdriving. */
/* Three steps of waveshaping are intended to modify */
/* waveform without boost/clipping/attenuation process. */
for(ot = 0;ot < 4;ot++)
{
ALfloat smp = oversample_buffer[it][ot];
ALfloat smp = buffer[1][it*4 + ot] * 4.0f;
smp = (1.0f + fc) * smp/(1.0f + fc*fabsf(smp));
smp = (1.0f + fc) * smp/(1.0f + fc*fabsf(smp)) * -1.0f;
smp = (1.0f + fc) * smp/(1.0f + fc*fabsf(smp));
/* Third step, do bandpass filtering of distorted signal */
smp = ALfilterState_processSingle(&state->bandpass, smp);
oversample_buffer[it][ot] = smp;
buffer[1][it*4 + ot] = smp;
}
}
/* Third step, do bandpass filtering of distorted signal */
ALfilterState_process(&state->bandpass, buffer[0], buffer[1], td*4);
for(kt = 0;kt < NumChannels;kt++)
{
/* Fourth step, final, do attenuation and perform decimation,
@@ -162,7 +154,7 @@ static ALvoid ALdistortionState_process(ALdistortionState *state, ALuint Samples
continue;
for(it = 0;it < td;it++)
SamplesOut[kt][base+it] += gain * oversample_buffer[it][0];
SamplesOut[kt][base+it] += gain * buffer[0][it*4];
}
base += td;