From 2a3b5ab9e9bf3a47bb61921c6c7d79ca0847a99b Mon Sep 17 00:00:00 2001 From: Chris Robinson Date: Fri, 15 Dec 2017 16:50:06 -0800 Subject: Use linear interpolation for the chorus delay output --- Alc/effects/chorus.c | 76 +++++++++++++++++++++++++++------------------------- 1 file changed, 39 insertions(+), 37 deletions(-) diff --git a/Alc/effects/chorus.c b/Alc/effects/chorus.c index ad978c3a..94e366cc 100644 --- a/Alc/effects/chorus.c +++ b/Alc/effects/chorus.c @@ -120,6 +120,7 @@ static ALvoid ALchorusState_update(ALchorusState *state, const ALCcontext *Conte const ALCdevice *device = Context->Device; ALfloat frequency = (ALfloat)device->Frequency; ALfloat coeffs[MAX_AMBI_COEFFS]; + ALfloat delay; ALfloat rate; ALint phase; @@ -132,10 +133,17 @@ static ALvoid ALchorusState_update(ALchorusState *state, const ALCcontext *Conte state->waveform = CWF_Sinusoid; break; } - state->feedback = props->Chorus.Feedback; - state->delay = fastf2i(props->Chorus.Delay * frequency); + /* The LFO depth is scaled to be relative to the sample delay. */ - state->depth = props->Chorus.Depth * state->delay; + delay = props->Chorus.Delay*frequency * FRACTIONONE; + state->depth = props->Chorus.Depth * delay; + + /* Offset the delay so that the center point remains the same with the LFO + * ranging from 0...2 instead of -1...+1. + */ + state->delay = fastf2i(delay - state->depth + 0.5f); + + state->feedback = props->Chorus.Feedback; /* Gains for left and right sides */ CalcAngleCoeffs(-F_PI_2, 0.0f, 0.0f, coeffs); @@ -180,7 +188,7 @@ static void GetTriangleDelays(ALint *restrict delays, ALsizei offset, const ALsi ALsizei i; for(i = 0;i < todo;i++) { - delays[i] = fastf2i((1.0f - fabsf(2.0f - lfo_scale*offset)) * depth) + delay; + delays[i] = fastf2i((2.0f - fabsf(2.0f - lfo_scale*offset)) * depth) + delay; offset = (offset+1)%lfo_range; } } @@ -192,7 +200,7 @@ static void GetSinusoidDelays(ALint *restrict delays, ALsizei offset, const ALsi ALsizei i; for(i = 0;i < todo;i++) { - delays[i] = fastf2i(sinf(lfo_scale*offset) * depth) + delay; + delays[i] = fastf2i((sinf(lfo_scale*offset)+1.0f) * depth) + delay; offset = (offset+1)%lfo_range; } } @@ -200,50 +208,46 @@ static void GetSinusoidDelays(ALint *restrict delays, ALsizei offset, const ALsi static ALvoid ALchorusState_process(ALchorusState *state, ALsizei SamplesToDo, const ALfloat (*restrict SamplesIn)[BUFFERSIZE], ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALsizei NumChannels) { - ALfloat *restrict leftbuf = state->SampleBuffer[0]; - ALfloat *restrict rightbuf = state->SampleBuffer[1]; const ALsizei bufmask = state->BufferLength-1; const ALfloat feedback = state->feedback; - ALsizei offset = state->offset; ALsizei i, c; ALsizei base; for(base = 0;base < SamplesToDo;) { const ALsizei todo = mini(128, SamplesToDo-base); - ALfloat temps[128][2]; - ALint moddelays[2][128]; + ALfloat temps[2][128]; + ALsizei offset; - switch(state->waveform) + for(c = 0;c < 2;c++) { - case CWF_Triangle: - GetTriangleDelays(moddelays[0], offset%state->lfo_range, state->lfo_range, - state->lfo_scale, state->depth, state->delay, todo); - GetTriangleDelays(moddelays[1], (offset+state->lfo_disp)%state->lfo_range, + ALfloat *restrict sampbuf = state->SampleBuffer[c]; + ALint disp_offset = state->lfo_disp*c; + ALint moddelays[128]; + + offset = state->offset; + if(state->waveform == CWF_Triangle) + GetTriangleDelays(moddelays, (offset+disp_offset)%state->lfo_range, state->lfo_range, state->lfo_scale, state->depth, state->delay, todo); - break; - case CWF_Sinusoid: - GetSinusoidDelays(moddelays[0], offset%state->lfo_range, state->lfo_range, - state->lfo_scale, state->depth, state->delay, todo); - GetSinusoidDelays(moddelays[1], (offset+state->lfo_disp)%state->lfo_range, + else /*if(state->waveform == CWF_Sinusoid)*/ + GetSinusoidDelays(moddelays, (offset+disp_offset)%state->lfo_range, state->lfo_range, state->lfo_scale, state->depth, state->delay, todo); - break; - } - - for(i = 0;i < todo;i++) - { - leftbuf[offset&bufmask] = SamplesIn[0][base+i]; - temps[i][0] = leftbuf[(offset-moddelays[0][i])&bufmask] * feedback; - leftbuf[offset&bufmask] += temps[i][0]; - rightbuf[offset&bufmask] = SamplesIn[0][base+i]; - temps[i][1] = rightbuf[(offset-moddelays[1][i])&bufmask] * feedback; - rightbuf[offset&bufmask] += temps[i][1]; - - offset++; + for(i = 0;i < todo;i++) + { + ALint delay = moddelays[i] >> FRACTIONBITS; + ALfloat mu = (moddelays[i]&FRACTIONMASK) * (1.0f/FRACTIONONE); + + sampbuf[offset&bufmask] = SamplesIn[0][base+i]; + temps[c][i] = (sampbuf[(offset-delay) & bufmask]*(1.0f-mu) + + sampbuf[(offset-(delay+1)) & bufmask]*mu) * feedback; + sampbuf[offset&bufmask] += temps[c][i]; + offset++; + } } + state->offset = offset; for(c = 0;c < NumChannels;c++) { @@ -251,21 +255,19 @@ static ALvoid ALchorusState_process(ALchorusState *state, ALsizei SamplesToDo, c if(fabsf(gain) > GAIN_SILENCE_THRESHOLD) { for(i = 0;i < todo;i++) - SamplesOut[c][i+base] += temps[i][0] * gain; + SamplesOut[c][i+base] += temps[0][i] * gain; } gain = state->Gain[1][c]; if(fabsf(gain) > GAIN_SILENCE_THRESHOLD) { for(i = 0;i < todo;i++) - SamplesOut[c][i+base] += temps[i][1] * gain; + SamplesOut[c][i+base] += temps[1][i] * gain; } } base += todo; } - - state->offset = offset; } -- cgit v1.2.3