diff options
| -rw-r--r-- | Alc/effects/flanger.c | 99 |
1 files changed, 55 insertions, 44 deletions
diff --git a/Alc/effects/flanger.c b/Alc/effects/flanger.c index 0db3321d..74a39364 100644 --- a/Alc/effects/flanger.c +++ b/Alc/effects/flanger.c @@ -41,6 +41,8 @@ typedef struct ALflangerState { ALfloat *SampleBuffer[2]; ALsizei BufferLength; ALsizei offset; + + ALsizei lfo_offset; ALsizei lfo_range; ALfloat lfo_scale; ALint lfo_disp; @@ -73,6 +75,7 @@ static void ALflangerState_Construct(ALflangerState *state) state->SampleBuffer[0] = NULL; state->SampleBuffer[1] = NULL; state->offset = 0; + state->lfo_offset = 0; state->lfo_range = 1; state->waveform = FWF_Triangle; } @@ -120,6 +123,7 @@ static ALvoid ALflangerState_update(ALflangerState *state, const ALCcontext *con const ALCdevice *device = context->Device; ALfloat frequency = (ALfloat)device->Frequency; ALfloat coeffs[MAX_AMBI_COEFFS]; + ALfloat delay; ALfloat rate; ALint phase; @@ -132,10 +136,17 @@ static ALvoid ALflangerState_update(ALflangerState *state, const ALCcontext *con state->waveform = FWF_Sinusoid; break; } - state->feedback = props->Flanger.Feedback; - state->delay = fastf2i(props->Flanger.Delay * frequency); + /* The LFO depth is scaled to be relative to the sample delay. */ - state->depth = props->Flanger.Depth * state->delay; + delay = props->Flanger.Delay*frequency * FRACTIONONE; + state->depth = props->Flanger.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->Flanger.Feedback; /* Gains for left and right sides */ CalcAngleCoeffs(-F_PI_2, 0.0f, 0.0f, coeffs); @@ -147,14 +158,21 @@ static ALvoid ALflangerState_update(ALflangerState *state, const ALCcontext *con rate = props->Flanger.Rate; if(!(rate > 0.0f)) { - state->lfo_scale = 0.0f; + state->lfo_offset = 1; state->lfo_range = 1; + state->lfo_scale = 0.0f; state->lfo_disp = 0; } else { - /* Calculate LFO coefficient */ - state->lfo_range = fastf2i(frequency/rate + 0.5f); + /* Calculate LFO coefficient (number of samples per cycle). Limit the + * max range to avoid overflow when calculating the displacement. + */ + ALsizei lfo_range = mini(fastf2i(frequency/rate + 0.5f), INT_MAX/360 - 180); + + state->lfo_offset = fastf2i((ALfloat)state->lfo_offset/state->lfo_range* + lfo_range + 0.5f) % lfo_range; + state->lfo_range = lfo_range; switch(state->waveform) { case FWF_Triangle: @@ -166,10 +184,8 @@ static ALvoid ALflangerState_update(ALflangerState *state, const ALCcontext *con } /* Calculate lfo phase displacement */ - if(phase >= 0) - state->lfo_disp = fastf2i(state->lfo_range * (phase/360.0f)); - else - state->lfo_disp = fastf2i(state->lfo_range * ((360+phase)/360.0f)); + if(phase < 0) phase = 360 + phase; + state->lfo_disp = (state->lfo_range*phase + 180) / 360; } } @@ -180,7 +196,7 @@ 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; } } @@ -192,57 +208,54 @@ 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; } } static ALvoid ALflangerState_process(ALflangerState *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 FWF_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]; + + if(state->waveform == FWF_Triangle) + GetTriangleDelays(moddelays, (state->lfo_offset+disp_offset)%state->lfo_range, state->lfo_range, state->lfo_scale, state->depth, state->delay, todo); - break; - case FWF_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 == FWF_Sinusoid)*/ + GetSinusoidDelays(moddelays, (state->lfo_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++; + offset = state->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; + state->lfo_offset = (state->lfo_offset+todo) % state->lfo_range; for(c = 0;c < NumChannels;c++) { @@ -250,21 +263,19 @@ static ALvoid ALflangerState_process(ALflangerState *state, ALsizei SamplesToDo, 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; } |