diff options
| -rw-r--r-- | Alc/alcModulator.c | 34 |
1 files changed, 28 insertions, 6 deletions
diff --git a/Alc/alcModulator.c b/Alc/alcModulator.c index 558e861b..b20cabaf 100644 --- a/Alc/alcModulator.c +++ b/Alc/alcModulator.c @@ -33,8 +33,25 @@ typedef struct ALmodulatorState { // Must be first in all effects! ALeffectState state; + + FILTER iirFilter; + ALfloat history[1]; } ALmodulatorState; + +static __inline ALfloat hpFilter1P(FILTER *iir, ALuint offset, ALfloat input) +{ + ALfloat *history = &iir->history[offset]; + ALfloat a = iir->coeff; + ALfloat output = input; + + output = output + (history[0]-output)*a; + history[0] = output; + + return input - output; +} + + static ALvoid ModulatorDestroy(ALeffectState *effect) { ALmodulatorState *state = (ALmodulatorState*)effect; @@ -44,15 +61,18 @@ static ALvoid ModulatorDestroy(ALeffectState *effect) static ALboolean ModulatorDeviceUpdate(ALeffectState *effect, ALCdevice *Device) { return AL_TRUE; - (void)Device; (void)effect; + (void)Device; } static ALvoid ModulatorUpdate(ALeffectState *effect, ALCcontext *Context, const ALeffect *Effect) { - (void)effect; - (void)Context; - (void)Effect; + ALmodulatorState *state = (ALmodulatorState*)effect; + ALfloat cw, a = 0.0f; + + cw = cos(2.0*M_PI * Effect->Modulator.HighPassCutoff / Context->Device->Frequency); + a = (2.0f-cw) - aluSqrt(aluPow(2.0f-cw, 2.0f) - 1.0f); + state->iirFilter.coeff = a; } static ALvoid ModulatorProcess(ALeffectState *effect, const ALeffectslot *Slot, ALuint SamplesToDo, const ALfloat *SamplesIn, ALfloat (*SamplesOut)[OUTPUTCHANNELS]) @@ -61,11 +81,10 @@ static ALvoid ModulatorProcess(ALeffectState *effect, const ALeffectslot *Slot, const ALfloat gain = Slot->Gain; ALfloat samp; ALuint i; - (void)state; for(i = 0;i < SamplesToDo;i++) { - samp = SamplesIn[i]; + samp = hpFilter1P(&state->iirFilter, 0, SamplesIn[i]); // Apply slot gain samp *= gain; @@ -92,5 +111,8 @@ ALeffectState *ModulatorCreate(void) state->state.Update = ModulatorUpdate; state->state.Process = ModulatorProcess; + state->iirFilter.coeff = 0.0f; + state->iirFilter.history[0] = 0.0f; + return &state->state; } |