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Move ALEQFilter to alFilter.c/h and rename it to ALfilterState

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This commit is contained in:
Chris Robinson
2013-05-27 15:32:02 -07:00
parent 0ad71a67d4
commit b1ae44206f
3 changed files with 131 additions and 107 deletions
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Alc/effects/equalizer.c
+10 -107
View File
@@ -78,20 +78,6 @@ static ALequalizerStateFactory EqualizerFactory;
* filter coefficients" by Robert Bristow-Johnson *
* http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt */
typedef enum ALEQFilterType {
LOW_SHELF,
HIGH_SHELF,
PEAKING
} ALEQFilterType;
typedef struct ALEQFilter {
ALEQFilterType type;
ALfloat x[2]; /* History of two last input samples */
ALfloat y[2]; /* History of two last output samples */
ALfloat a[3]; /* Transfer function coefficients "a" */
ALfloat b[3]; /* Transfer function coefficients "b" */
} ALEQFilter;
typedef struct ALequalizerState {
DERIVE_FROM_TYPE(ALeffectState);
@@ -99,7 +85,7 @@ typedef struct ALequalizerState {
ALfloat Gain[MaxChannels];
/* Effect parameters */
ALEQFilter bandfilter[4];
ALfilterState filter[4];
} ALequalizerState;
static ALvoid ALequalizerState_Destruct(ALequalizerState *state)
@@ -131,11 +117,10 @@ static ALvoid ALequalizerState_Update(ALequalizerState *state, ALCdevice *device
/* Calculate coefficients for the each type of filter */
for(it = 0; it < 4; it++)
{
ALfloat gain;
ALfilterType type = ALfilterType_Peaking;
ALfloat filter_frequency;
ALfloat bandwidth = 0.0f;
ALfloat w0;
ALfloat alpha = 0.0f;
ALfloat gain;
/* convert linear gains to filter gains */
switch (it)
@@ -143,85 +128,28 @@ static ALvoid ALequalizerState_Update(ALequalizerState *state, ALCdevice *device
case 0: /* Low Shelf */
gain = powf(10.0f, (20.0f * log10f(slot->EffectProps.Equalizer.LowGain)) / 40.0f);
filter_frequency = slot->EffectProps.Equalizer.LowCutoff;
type = ALfilterType_LowShelf;
break;
case 1: /* Peaking */
gain = powf(10.0f, (20.0f * log10f(slot->EffectProps.Equalizer.Mid1Gain)) / 40.0f);
filter_frequency = slot->EffectProps.Equalizer.Mid1Center;
bandwidth = slot->EffectProps.Equalizer.Mid1Width;
type = ALfilterType_Peaking;
break;
case 2: /* Peaking */
gain = powf(10.0f, (20.0f * log10f(slot->EffectProps.Equalizer.Mid2Gain)) / 40.0f);
filter_frequency = slot->EffectProps.Equalizer.Mid2Center;
bandwidth = slot->EffectProps.Equalizer.Mid2Width;
type = ALfilterType_Peaking;
break;
case 3: /* High Shelf */
gain = powf(10.0f, (20.0f * log10f(slot->EffectProps.Equalizer.HighGain)) / 40.0f);
filter_frequency = slot->EffectProps.Equalizer.HighCutoff;
type = ALfilterType_HighShelf;
break;
}
w0 = 2.0f*F_PI * filter_frequency / frequency;
/* Calculate filter coefficients depending on filter type */
switch(state->bandfilter[it].type)
{
case LOW_SHELF:
alpha = sinf(w0) / 2.0f * sqrtf((gain + 1.0f / gain) *
(1.0f / 0.75f - 1.0f) + 2.0f);
state->bandfilter[it].b[0] = gain * ((gain + 1.0f) -
(gain - 1.0f) * cosf(w0) +
2.0f * sqrtf(gain) * alpha);
state->bandfilter[it].b[1] = 2.0f * gain * ((gain - 1.0f) -
(gain + 1.0f) * cosf(w0));
state->bandfilter[it].b[2] = gain * ((gain + 1.0f) -
(gain - 1.0f) * cosf(w0) -
2.0f * sqrtf(gain) * alpha);
state->bandfilter[it].a[0] = (gain + 1.0f) +
(gain - 1.0f) * cosf(w0) +
2.0f * sqrtf(gain) * alpha;
state->bandfilter[it].a[1] = -2.0f * ((gain - 1.0f) +
(gain + 1.0f) * cosf(w0));
state->bandfilter[it].a[2] = (gain + 1.0f) +
(gain - 1.0f) * cosf(w0) -
2.0f * sqrtf(gain) * alpha;
break;
case HIGH_SHELF:
alpha = sinf(w0) / 2.0f * sqrtf((gain + 1.0f / gain) *
(1.0f / 0.75f - 1.0f) + 2.0f);
state->bandfilter[it].b[0] = gain * ((gain + 1.0f) +
(gain - 1.0f) * cosf(w0) +
2.0f * sqrtf(gain) * alpha);
state->bandfilter[it].b[1] = -2.0f * gain * ((gain - 1.0f) +
(gain + 1.0f) *
cosf(w0));
state->bandfilter[it].b[2] = gain * ((gain + 1.0f) +
(gain - 1.0f) * cosf(w0) -
2.0f * sqrtf(gain) * alpha);
state->bandfilter[it].a[0] = (gain + 1.0f) -
(gain - 1.0f) * cosf(w0) +
2.0f * sqrtf(gain) * alpha;
state->bandfilter[it].a[1] = 2.0f * ((gain - 1.0f) -
(gain + 1.0f) * cosf(w0));
state->bandfilter[it].a[2] = (gain + 1.0f) -
(gain - 1.0f) * cosf(w0) -
2.0f * sqrtf(gain) * alpha;
break;
case PEAKING:
alpha = sinf(w0) * sinhf(logf(2.0f) / 2.0f * bandwidth * w0 / sinf(w0));
state->bandfilter[it].b[0] = 1.0f + alpha * gain;
state->bandfilter[it].b[1] = -2.0f * cosf(w0);
state->bandfilter[it].b[2] = 1.0f - alpha * gain;
state->bandfilter[it].a[0] = 1.0f + alpha / gain;
state->bandfilter[it].a[1] = -2.0f * cosf(w0);
state->bandfilter[it].a[2] = 1.0f - alpha / gain;
break;
}
state->bandfilter[it].b[0] /= state->bandfilter[it].a[0];
state->bandfilter[it].b[1] /= state->bandfilter[it].a[0];
state->bandfilter[it].b[2] /= state->bandfilter[it].a[0];
state->bandfilter[it].a[0] /= state->bandfilter[it].a[0];
state->bandfilter[it].a[1] /= state->bandfilter[it].a[0];
state->bandfilter[it].a[2] /= state->bandfilter[it].a[0];
ALfilterState_setParams(&state->filter[it], type, gain, filter_frequency/frequency, bandwidth);
}
}
@@ -242,22 +170,7 @@ static ALvoid ALequalizerState_Process(ALequalizerState *state, ALuint SamplesTo
ALfloat smp = SamplesIn[base+it];
for(ft = 0;ft < 4;ft++)
{
ALEQFilter *filter = &state->bandfilter[ft];
ALfloat outsmp;
outsmp = filter->b[0] * smp +
filter->b[1] * filter->x[0] +
filter->b[2] * filter->x[1] -
filter->a[1] * filter->y[0] -
filter->a[2] * filter->y[1];
filter->x[1] = filter->x[0];
filter->x[0] = smp;
filter->y[1] = filter->y[0];
filter->y[0] = outsmp;
smp = outsmp;
}
smp = ALfilterState_processSingle(&state->filter[ft], smp);
temps[it] = smp;
}
@@ -294,20 +207,10 @@ ALeffectState *ALequalizerStateFactory_create(ALequalizerStateFactory *factory)
if(!state) return NULL;
SET_VTABLE2(ALequalizerState, ALeffectState, state);
state->bandfilter[0].type = LOW_SHELF;
state->bandfilter[1].type = PEAKING;
state->bandfilter[2].type = PEAKING;
state->bandfilter[3].type = HIGH_SHELF;
/* Initialize sample history only on filter creation to avoid */
/* sound clicks if filter settings were changed in runtime. */
for(it = 0; it < 4; it++)
{
state->bandfilter[it].x[0] = 0.0f;
state->bandfilter[it].x[1] = 0.0f;
state->bandfilter[it].y[0] = 0.0f;
state->bandfilter[it].y[1] = 0.0f;
}
ALfilterState_clear(&state->filter[it]);
return STATIC_CAST(ALeffectState, state);
}
OpenAL32/Include/alFilter.h
+43
View File
@@ -46,6 +46,49 @@ static __inline ALfloat lpFilter2PC(const FILTER *iir, ALfloat input)
ALfloat lpCoeffCalc(ALfloat g, ALfloat cw);
typedef enum ALfilterType {
ALfilterType_HighShelf,
ALfilterType_LowShelf,
ALfilterType_Peaking,
} ALfilterType;
typedef struct ALfilterState {
ALfloat x[2]; /* History of two last input samples */
ALfloat y[2]; /* History of two last output samples */
ALfloat a[3]; /* Transfer function coefficients "a" */
ALfloat b[3]; /* Transfer function coefficients "b" */
} ALfilterState;
void ALfilterState_clear(ALfilterState *filter);
void ALfilterState_setParams(ALfilterState *filter, ALfilterType type, ALfloat gain, ALfloat freq_scale, ALfloat bandwidth);
static __inline ALfloat ALfilterState_processSingle(ALfilterState *filter, ALfloat sample)
{
ALfloat outsmp;
outsmp = filter->b[0] * sample +
filter->b[1] * filter->x[0] +
filter->b[2] * filter->x[1] -
filter->a[1] * filter->y[0] -
filter->a[2] * filter->y[1];
filter->x[1] = filter->x[0];
filter->x[0] = sample;
filter->y[1] = filter->y[0];
filter->y[0] = outsmp;
return outsmp;
}
static __inline ALfloat ALfilterState_processSingleC(const ALfilterState *filter, ALfloat sample)
{
return filter->b[0] * sample +
filter->b[1] * filter->x[0] +
filter->b[2] * filter->x[1] -
filter->a[1] * filter->y[0] -
filter->a[2] * filter->y[1];
}
typedef struct ALfilter {
// Filter type (AL_FILTER_NULL, ...)
ALenum type;
OpenAL32/alFilter.c
+78
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@@ -325,6 +325,84 @@ AL_API ALvoid AL_APIENTRY alGetFilterfv(ALuint filter, ALenum param, ALfloat *va
}
void ALfilterState_clear(ALfilterState *filter)
{
filter->x[0] = 0.0f;
filter->x[1] = 0.0f;
filter->y[0] = 0.0f;
filter->y[1] = 0.0f;
}
void ALfilterState_setParams(ALfilterState *filter, ALfilterType type, ALfloat gain, ALfloat freq_scale, ALfloat bandwidth)
{
ALfloat alpha;
ALfloat w0;
w0 = 2.0f*F_PI * freq_scale;
/* Calculate filter coefficients depending on filter type */
switch(type)
{
case ALfilterType_HighShelf:
alpha = sinf(w0) / 2.0f * sqrtf((gain + 1.0f/gain) *
(1.0f/0.75f - 1.0f) + 2.0f);
filter->b[0] = gain * ((gain + 1.0f) +
(gain - 1.0f) * cosf(w0) +
2.0f * sqrtf(gain) * alpha);
filter->b[1] = -2.0f * gain * ((gain - 1.0f) +
(gain + 1.0f) * cosf(w0));
filter->b[2] = gain * ((gain + 1.0f) +
(gain - 1.0f) * cosf(w0) -
2.0f * sqrtf(gain) * alpha);
filter->a[0] = (gain + 1.0f) -
(gain - 1.0f) * cosf(w0) +
2.0f * sqrtf(gain) * alpha;
filter->a[1] = 2.0f * ((gain - 1.0f) -
(gain + 1.0f) * cosf(w0));
filter->a[2] = (gain + 1.0f) -
(gain - 1.0f) * cosf(w0) -
2.0f * sqrtf(gain) * alpha;
break;
case ALfilterType_LowShelf:
alpha = sinf(w0) / 2.0f * sqrtf((gain + 1.0f / gain) *
(1.0f / 0.75f - 1.0f) + 2.0f);
filter->b[0] = gain * ((gain + 1.0f) -
(gain - 1.0f) * cosf(w0) +
2.0f * sqrtf(gain) * alpha);
filter->b[1] = 2.0f * gain * ((gain - 1.0f) -
(gain + 1.0f) * cosf(w0));
filter->b[2] = gain * ((gain + 1.0f) -
(gain - 1.0f) * cosf(w0) -
2.0f * sqrtf(gain) * alpha);
filter->a[0] = (gain + 1.0f) +
(gain - 1.0f) * cosf(w0) +
2.0f * sqrtf(gain) * alpha;
filter->a[1] = -2.0f * ((gain - 1.0f) +
(gain + 1.0f) * cosf(w0));
filter->a[2] = (gain + 1.0f) +
(gain - 1.0f) * cosf(w0) -
2.0f * sqrtf(gain) * alpha;
break;
case ALfilterType_Peaking:
alpha = sinf(w0) * sinhf(logf(2.0f) / 2.0f * bandwidth * w0 / sinf(w0));
filter->b[0] = 1.0f + alpha * gain;
filter->b[1] = -2.0f * cosf(w0);
filter->b[2] = 1.0f - alpha * gain;
filter->a[0] = 1.0f + alpha / gain;
filter->a[1] = -2.0f * cosf(w0);
filter->a[2] = 1.0f - alpha / gain;
break;
}
filter->b[0] /= filter->a[0];
filter->b[1] /= filter->a[0];
filter->b[2] /= filter->a[0];
filter->a[0] /= filter->a[0];
filter->a[1] /= filter->a[0];
filter->a[2] /= filter->a[0];
}
ALfloat lpCoeffCalc(ALfloat g, ALfloat cw)
{
ALfloat a = 0.0f;