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authorChris Robinson <[email protected]>2013-05-23 21:33:16 -0700
committerChris Robinson <[email protected]>2013-05-23 21:33:16 -0700
commit357cf72ab33ef1807da8ea6ce4633fd8e2a89553 (patch)
treee8fc4fb0183ae56bf15c31f9bf28890201ee143c /Alc/effects/equalizer.c
parent23766831282507bc09b223b4ecb645490b5fab0b (diff)
Move remaining effects to the effects subdir
Diffstat (limited to 'Alc/effects/equalizer.c')
-rw-r--r--Alc/effects/equalizer.c499
1 files changed, 499 insertions, 0 deletions
diff --git a/Alc/effects/equalizer.c b/Alc/effects/equalizer.c
new file mode 100644
index 00000000..d397a9ba
--- /dev/null
+++ b/Alc/effects/equalizer.c
@@ -0,0 +1,499 @@
+/**
+ * OpenAL cross platform audio library
+ * Copyright (C) 2013 by Mike Gorchak
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ * Or go to http://www.gnu.org/copyleft/lgpl.html
+ */
+
+#include "config.h"
+
+#include <math.h>
+#include <stdlib.h>
+
+#include "alMain.h"
+#include "alFilter.h"
+#include "alAuxEffectSlot.h"
+#include "alError.h"
+#include "alu.h"
+
+
+typedef struct ALequalizerStateFactory {
+ DERIVE_FROM_TYPE(ALeffectStateFactory);
+} ALequalizerStateFactory;
+
+static ALequalizerStateFactory EqualizerFactory;
+
+
+/* The document "Effects Extension Guide.pdf" says that low and high *
+ * frequencies are cutoff frequencies. This is not fully correct, they *
+ * are corner frequencies for low and high shelf filters. If they were *
+ * just cutoff frequencies, there would be no need in cutoff frequency *
+ * gains, which are present. Documentation for "Creative Proteus X2" *
+ * software describes 4-band equalizer functionality in a much better *
+ * way. This equalizer seems to be a predecessor of OpenAL 4-band *
+ * equalizer. With low and high shelf filters we are able to cutoff *
+ * frequencies below and/or above corner frequencies using attenuation *
+ * gains (below 1.0) and amplify all low and/or high frequencies using *
+ * gains above 1.0. *
+ * *
+ * Low-shelf Low Mid Band High Mid Band High-shelf *
+ * corner center center corner *
+ * frequency frequency frequency frequency *
+ * 50Hz..800Hz 200Hz..3000Hz 1000Hz..8000Hz 4000Hz..16000Hz *
+ * *
+ * | | | | *
+ * | | | | *
+ * B -----+ /--+--\ /--+--\ +----- *
+ * O |\ | | | | | | /| *
+ * O | \ - | - - | - / | *
+ * S + | \ | | | | | | / | *
+ * T | | | | | | | | | | *
+ * ---------+---------------+------------------+---------------+-------- *
+ * C | | | | | | | | | | *
+ * U - | / | | | | | | \ | *
+ * T | / - | - - | - \ | *
+ * O |/ | | | | | | \| *
+ * F -----+ \--+--/ \--+--/ +----- *
+ * F | | | | *
+ * | | | | *
+ * *
+ * Gains vary from 0.126 up to 7.943, which means from -18dB attenuation *
+ * up to +18dB amplification. Band width varies from 0.01 up to 1.0 in *
+ * octaves for two mid bands. *
+ * *
+ * Implementation is based on the "Cookbook formulae for audio EQ biquad *
+ * 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);
+
+ /* Effect gains for each channel */
+ ALfloat Gain[MaxChannels];
+
+ /* Effect parameters */
+ ALEQFilter bandfilter[4];
+} ALequalizerState;
+
+static ALvoid ALequalizerState_Destruct(ALequalizerState *state)
+{
+ (void)state;
+}
+
+static ALboolean ALequalizerState_DeviceUpdate(ALequalizerState *state, ALCdevice *device)
+{
+ return AL_TRUE;
+ (void)state;
+ (void)device;
+}
+
+static ALvoid ALequalizerState_Update(ALequalizerState *state, ALCdevice *device, const ALeffectslot *slot)
+{
+ ALfloat frequency = (ALfloat)device->Frequency;
+ ALfloat gain = sqrtf(1.0f / device->NumChan) * slot->Gain;
+ ALuint it;
+
+ for(it = 0;it < MaxChannels;it++)
+ state->Gain[it] = 0.0f;
+ for(it = 0; it < device->NumChan; it++)
+ {
+ enum Channel chan = device->Speaker2Chan[it];
+ state->Gain[chan] = gain;
+ }
+
+ /* Calculate coefficients for the each type of filter */
+ for(it = 0; it < 4; it++)
+ {
+ ALfloat gain;
+ ALfloat filter_frequency;
+ ALfloat bandwidth = 0.0f;
+ ALfloat w0;
+ ALfloat alpha = 0.0f;
+
+ /* convert linear gains to filter gains */
+ switch (it)
+ {
+ case 0: /* Low Shelf */
+ gain = powf(10.0f, (20.0f * log10f(slot->effect.Equalizer.LowGain)) / 40.0f);
+ filter_frequency = slot->effect.Equalizer.LowCutoff;
+ break;
+ case 1: /* Peaking */
+ gain = powf(10.0f, (20.0f * log10f(slot->effect.Equalizer.Mid1Gain)) / 40.0f);
+ filter_frequency = slot->effect.Equalizer.Mid1Center;
+ bandwidth = slot->effect.Equalizer.Mid1Width;
+ break;
+ case 2: /* Peaking */
+ gain = powf(10.0f, (20.0f * log10f(slot->effect.Equalizer.Mid2Gain)) / 40.0f);
+ filter_frequency = slot->effect.Equalizer.Mid2Center;
+ bandwidth = slot->effect.Equalizer.Mid2Width;
+ break;
+ case 3: /* High Shelf */
+ gain = powf(10.0f, (20.0f * log10f(slot->effect.Equalizer.HighGain)) / 40.0f);
+ filter_frequency = slot->effect.Equalizer.HighCutoff;
+ 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;
+ }
+ }
+}
+
+static ALvoid ALequalizerState_Process(ALequalizerState *state, ALuint SamplesToDo, const ALfloat *restrict SamplesIn, ALfloat (*restrict SamplesOut)[BUFFERSIZE])
+{
+ ALuint base;
+ ALuint it;
+ ALuint kt;
+ ALuint ft;
+
+ for(base = 0;base < SamplesToDo;)
+ {
+ ALfloat temps[64];
+ ALuint td = minu(SamplesToDo-base, 64);
+
+ for(it = 0;it < td;it++)
+ {
+ ALfloat smp = SamplesIn[base+it];
+ ALfloat tempsmp;
+
+ for(ft = 0;ft < 4;ft++)
+ {
+ ALEQFilter *filter = &state->bandfilter[ft];
+
+ tempsmp = filter->b[0] / filter->a[0] * smp +
+ filter->b[1] / filter->a[0] * filter->x[0] +
+ filter->b[2] / filter->a[0] * filter->x[1] -
+ filter->a[1] / filter->a[0] * filter->y[0] -
+ filter->a[2] / filter->a[0] * filter->y[1];
+
+ filter->x[1] = filter->x[0];
+ filter->x[0] = smp;
+ filter->y[1] = filter->y[0];
+ filter->y[0] = tempsmp;
+ smp = tempsmp;
+ }
+
+ temps[it] = smp;
+ }
+
+ for(kt = 0;kt < MaxChannels;kt++)
+ {
+ ALfloat gain = state->Gain[kt];
+ if(!(gain > 0.00001f))
+ continue;
+
+ for(it = 0;it < td;it++)
+ SamplesOut[kt][base+it] += gain * temps[it];
+ }
+
+ base += td;
+ }
+}
+
+static ALeffectStateFactory *ALequalizerState_getCreator(void)
+{
+ return STATIC_CAST(ALeffectStateFactory, &EqualizerFactory);
+}
+
+DEFINE_ALEFFECTSTATE_VTABLE(ALequalizerState);
+
+
+ALeffectState *ALequalizerStateFactory_create(void)
+{
+ ALequalizerState *state;
+ int it;
+
+ state = malloc(sizeof(*state));
+ 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;
+ }
+
+ return STATIC_CAST(ALeffectState, state);
+}
+
+static ALvoid ALequalizerStateFactory_destroy(ALeffectState *effect)
+{
+ ALequalizerState *state = STATIC_UPCAST(ALequalizerState, ALeffectState, effect);
+ ALequalizerState_Destruct(state);
+ free(state);
+}
+
+DEFINE_ALEFFECTSTATEFACTORY_VTABLE(ALequalizerStateFactory);
+
+
+static void init_equalizer_factory(void)
+{
+ SET_VTABLE2(ALequalizerStateFactory, ALeffectStateFactory, &EqualizerFactory);
+}
+
+ALeffectStateFactory *ALequalizerStateFactory_getFactory(void)
+{
+ static pthread_once_t once = PTHREAD_ONCE_INIT;
+ pthread_once(&once, init_equalizer_factory);
+ return STATIC_CAST(ALeffectStateFactory, &EqualizerFactory);
+}
+
+
+void equalizer_SetParami(ALeffect *effect, ALCcontext *context, ALenum param, ALint val)
+{
+ effect=effect;
+ val=val;
+
+ switch(param)
+ {
+ default:
+ alSetError(context, AL_INVALID_ENUM);
+ break;
+ }
+}
+void equalizer_SetParamiv(ALeffect *effect, ALCcontext *context, ALenum param, const ALint *vals)
+{
+ equalizer_SetParami(effect, context, param, vals[0]);
+}
+void equalizer_SetParamf(ALeffect *effect, ALCcontext *context, ALenum param, ALfloat val)
+{
+ switch(param)
+ {
+ case AL_EQUALIZER_LOW_GAIN:
+ if(val >= AL_EQUALIZER_MIN_LOW_GAIN && val <= AL_EQUALIZER_MAX_LOW_GAIN)
+ effect->Equalizer.LowGain = val;
+ else
+ alSetError(context, AL_INVALID_VALUE);
+ break;
+
+ case AL_EQUALIZER_LOW_CUTOFF:
+ if(val >= AL_EQUALIZER_MIN_LOW_CUTOFF && val <= AL_EQUALIZER_MAX_LOW_CUTOFF)
+ effect->Equalizer.LowCutoff = val;
+ else
+ alSetError(context, AL_INVALID_VALUE);
+ break;
+
+ case AL_EQUALIZER_MID1_GAIN:
+ if(val >= AL_EQUALIZER_MIN_MID1_GAIN && val <= AL_EQUALIZER_MAX_MID1_GAIN)
+ effect->Equalizer.Mid1Gain = val;
+ else
+ alSetError(context, AL_INVALID_VALUE);
+ break;
+
+ case AL_EQUALIZER_MID1_CENTER:
+ if(val >= AL_EQUALIZER_MIN_MID1_CENTER && val <= AL_EQUALIZER_MAX_MID1_CENTER)
+ effect->Equalizer.Mid1Center = val;
+ else
+ alSetError(context, AL_INVALID_VALUE);
+ break;
+
+ case AL_EQUALIZER_MID1_WIDTH:
+ if(val >= AL_EQUALIZER_MIN_MID1_WIDTH && val <= AL_EQUALIZER_MAX_MID1_WIDTH)
+ effect->Equalizer.Mid1Width = val;
+ else
+ alSetError(context, AL_INVALID_VALUE);
+ break;
+
+ case AL_EQUALIZER_MID2_GAIN:
+ if(val >= AL_EQUALIZER_MIN_MID2_GAIN && val <= AL_EQUALIZER_MAX_MID2_GAIN)
+ effect->Equalizer.Mid2Gain = val;
+ else
+ alSetError(context, AL_INVALID_VALUE);
+ break;
+
+ case AL_EQUALIZER_MID2_CENTER:
+ if(val >= AL_EQUALIZER_MIN_MID2_CENTER && val <= AL_EQUALIZER_MAX_MID2_CENTER)
+ effect->Equalizer.Mid2Center = val;
+ else
+ alSetError(context, AL_INVALID_VALUE);
+ break;
+
+ case AL_EQUALIZER_MID2_WIDTH:
+ if(val >= AL_EQUALIZER_MIN_MID2_WIDTH && val <= AL_EQUALIZER_MAX_MID2_WIDTH)
+ effect->Equalizer.Mid2Width = val;
+ else
+ alSetError(context, AL_INVALID_VALUE);
+ break;
+
+ case AL_EQUALIZER_HIGH_GAIN:
+ if(val >= AL_EQUALIZER_MIN_HIGH_GAIN && val <= AL_EQUALIZER_MAX_HIGH_GAIN)
+ effect->Equalizer.HighGain = val;
+ else
+ alSetError(context, AL_INVALID_VALUE);
+ break;
+
+ case AL_EQUALIZER_HIGH_CUTOFF:
+ if(val >= AL_EQUALIZER_MIN_HIGH_CUTOFF && val <= AL_EQUALIZER_MAX_HIGH_CUTOFF)
+ effect->Equalizer.HighCutoff = val;
+ else
+ alSetError(context, AL_INVALID_VALUE);
+ break;
+
+ default:
+ alSetError(context, AL_INVALID_ENUM);
+ break;
+ }
+}
+void equalizer_SetParamfv(ALeffect *effect, ALCcontext *context, ALenum param, const ALfloat *vals)
+{
+ equalizer_SetParamf(effect, context, param, vals[0]);
+}
+
+void equalizer_GetParami(ALeffect *effect, ALCcontext *context, ALenum param, ALint *val)
+{
+ effect=effect;
+ val=val;
+
+ switch(param)
+ {
+ default:
+ alSetError(context, AL_INVALID_ENUM);
+ break;
+ }
+}
+void equalizer_GetParamiv(ALeffect *effect, ALCcontext *context, ALenum param, ALint *vals)
+{
+ equalizer_GetParami(effect, context, param, vals);
+}
+void equalizer_GetParamf(ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *val)
+{
+ switch(param)
+ {
+ case AL_EQUALIZER_LOW_GAIN:
+ *val = effect->Equalizer.LowGain;
+ break;
+
+ case AL_EQUALIZER_LOW_CUTOFF:
+ *val = effect->Equalizer.LowCutoff;
+ break;
+
+ case AL_EQUALIZER_MID1_GAIN:
+ *val = effect->Equalizer.Mid1Gain;
+ break;
+
+ case AL_EQUALIZER_MID1_CENTER:
+ *val = effect->Equalizer.Mid1Center;
+ break;
+
+ case AL_EQUALIZER_MID1_WIDTH:
+ *val = effect->Equalizer.Mid1Width;
+ break;
+
+ case AL_EQUALIZER_MID2_GAIN:
+ *val = effect->Equalizer.Mid2Gain;
+ break;
+
+ case AL_EQUALIZER_MID2_CENTER:
+ *val = effect->Equalizer.Mid2Center;
+ break;
+
+ case AL_EQUALIZER_MID2_WIDTH:
+ *val = effect->Equalizer.Mid2Width;
+ break;
+
+ case AL_EQUALIZER_HIGH_GAIN:
+ *val = effect->Equalizer.HighGain;
+ break;
+
+ case AL_EQUALIZER_HIGH_CUTOFF:
+ *val = effect->Equalizer.HighCutoff;
+ break;
+
+ default:
+ alSetError(context, AL_INVALID_ENUM);
+ break;
+ }
+}
+void equalizer_GetParamfv(ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *vals)
+{
+ equalizer_GetParamf(effect, context, param, vals);
+}