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Use ALfilterState for the modulator high pass filter

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This commit is contained in:
Chris Robinson 2013-05-27 21:24:28 -07:00
parent 0c7c5327c9
commit 59a38442ac
1 changed files with 12 additions and 25 deletions
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37
Alc/effects/modulator.c
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@ -37,11 +37,6 @@ typedef struct ALmodulatorStateFactory {
static ALmodulatorStateFactory ModulatorFactory;
typedef struct {
ALfloat coeff;
ALfloat history[2];
} FILTER;
typedef struct ALmodulatorState {
DERIVE_FROM_TYPE(ALeffectState);
@ -56,7 +51,7 @@ typedef struct ALmodulatorState {
ALfloat Gain[MaxChannels];
FILTER iirFilter;
ALfilterState Filter;
} ALmodulatorState;
#define WAVEFORM_FRACBITS 24
@ -78,20 +73,6 @@ static __inline ALfloat Square(ALuint index)
return (ALfloat)((index >> (WAVEFORM_FRACBITS - 1)) & 1);
}
static __inline ALfloat hpFilter1P(FILTER *iir, ALfloat input)
{
ALfloat *history = iir->history;
ALfloat a = iir->coeff;
ALfloat output = input;
output = output + (history[0]-output)*a;
history[0] = output;
return input - output;
}
#define DECL_TEMPLATE(func) \
static void Process##func(ALmodulatorState *state, ALuint SamplesToDo, \
const ALfloat *restrict SamplesIn, \
@ -111,7 +92,7 @@ static void Process##func(ALmodulatorState *state, ALuint SamplesToDo, \
{ \
ALfloat samp; \
samp = SamplesIn[base+i]; \
samp = hpFilter1P(&state->iirFilter, samp); \
samp = ALfilterState_processSingle(&state->Filter, samp); \
\
index += step; \
index &= WAVEFORM_FRACMASK; \
@ -154,7 +135,7 @@ static ALboolean ALmodulatorState_DeviceUpdate(ALmodulatorState *state, ALCdevic
static ALvoid ALmodulatorState_Update(ALmodulatorState *state, ALCdevice *Device, const ALeffectslot *Slot)
{
ALfloat gain, cw, a = 0.0f;
ALfloat gain, cw, a;
ALuint index;
if(Slot->EffectProps.Modulator.Waveform == AL_RING_MODULATOR_SINUSOID)
@ -168,10 +149,17 @@ static ALvoid ALmodulatorState_Update(ALmodulatorState *state, ALCdevice *Device
Device->Frequency);
if(state->step == 0) state->step = 1;
/* Custom filter coeffs, which match the old version instead of a low-shelf. */
cw = cosf(F_PI*2.0f * Slot->EffectProps.Modulator.HighPassCutoff /
Device->Frequency);
a = (2.0f-cw) - sqrtf(powf(2.0f-cw, 2.0f) - 1.0f);
state->iirFilter.coeff = a;
state->Filter.b[0] = a;
state->Filter.b[1] = -a;
state->Filter.b[2] = 0.0f;
state->Filter.a[0] = 1.0f;
state->Filter.a[1] = -a;
state->Filter.a[2] = 0.0f;
gain = sqrtf(1.0f/Device->NumChan);
gain *= Slot->Gain;
@ -222,8 +210,7 @@ static ALeffectState *ALmodulatorStateFactory_create(ALmodulatorStateFactory *fa
state->index = 0;
state->step = 1;
state->iirFilter.coeff = 0.0f;
state->iirFilter.history[0] = 0.0f;
ALfilterState_clear(&state->Filter);
return STATIC_CAST(ALeffectState, state);
}