/**
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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"
/* 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 struct ALequalizerState {
DERIVE_FROM_TYPE(ALeffectState);
struct {
/* Effect gains for each channel */
ALfloat CurrentGains[MAX_OUTPUT_CHANNELS];
ALfloat TargetGains[MAX_OUTPUT_CHANNELS];
/* Effect parameters */
ALfilterState filter[4];
} Chans[MAX_EFFECT_CHANNELS];
ALfloat SampleBuffer[MAX_EFFECT_CHANNELS][BUFFERSIZE];
} ALequalizerState;
static ALvoid ALequalizerState_Destruct(ALequalizerState *state);
static ALboolean ALequalizerState_deviceUpdate(ALequalizerState *state, ALCdevice *device);
static ALvoid ALequalizerState_update(ALequalizerState *state, const ALCcontext *context, const ALeffectslot *slot, const ALeffectProps *props);
static ALvoid ALequalizerState_process(ALequalizerState *state, ALsizei SamplesToDo, const ALfloat (*restrict SamplesIn)[BUFFERSIZE], ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALsizei NumChannels);
DECLARE_DEFAULT_ALLOCATORS(ALequalizerState)
DEFINE_ALEFFECTSTATE_VTABLE(ALequalizerState);
static void ALequalizerState_Construct(ALequalizerState *state)
{
ALeffectState_Construct(STATIC_CAST(ALeffectState, state));
SET_VTABLE2(ALequalizerState, ALeffectState, state);
}
static ALvoid ALequalizerState_Destruct(ALequalizerState *state)
{
ALeffectState_Destruct(STATIC_CAST(ALeffectState,state));
}
static ALboolean ALequalizerState_deviceUpdate(ALequalizerState *state, ALCdevice *UNUSED(device))
{
ALsizei i, j;
for(i = 0; i < MAX_EFFECT_CHANNELS;i++)
{
for(j = 0;j < 4;j++)
ALfilterState_clear(&state->Chans[i].filter[j]);
for(j = 0;j < MAX_OUTPUT_CHANNELS;j++)
state->Chans[i].CurrentGains[j] = 0.0f;
}
return AL_TRUE;
}
static ALvoid ALequalizerState_update(ALequalizerState *state, const ALCcontext *context, const ALeffectslot *slot, const ALeffectProps *props)
{
const ALCdevice *device = context->Device;
ALfloat frequency = (ALfloat)device->Frequency;
ALfloat gain, f0norm;
ALuint i;
STATIC_CAST(ALeffectState,state)->OutBuffer = device->FOAOut.Buffer;
STATIC_CAST(ALeffectState,state)->OutChannels = device->FOAOut.NumChannels;
for(i = 0;i < MAX_EFFECT_CHANNELS;i++)
ComputeFirstOrderGains(&device->FOAOut, IdentityMatrixf.m[i],
slot->Params.Gain, state->Chans[i].TargetGains);
/* Calculate coefficients for the each type of filter. Note that the shelf
* filters' gain is for the reference frequency, which is the centerpoint
* of the transition band.
*/
gain = maxf(sqrtf(props->Equalizer.LowGain), 0.0625f); /* Limit -24dB */
f0norm = props->Equalizer.LowCutoff/frequency;
ALfilterState_setParams(&state->Chans[0].filter[0], ALfilterType_LowShelf,
gain, f0norm, calc_rcpQ_from_slope(gain, 0.75f)
);
gain = maxf(props->Equalizer.Mid1Gain, 0.0625f);
f0norm = props->Equalizer.Mid1Center/frequency;
ALfilterState_setParams(&state->Chans[0].filter[1], ALfilterType_Peaking,
gain, f0norm, calc_rcpQ_from_bandwidth(
f0norm, props->Equalizer.Mid1Width
)
);
gain = maxf(props->Equalizer.Mid2Gain, 0.0625f);
f0norm = props->Equalizer.Mid2Center/frequency;
ALfilterState_setParams(&state->Chans[0].filter[2], ALfilterType_Peaking,
gain, f0norm, calc_rcpQ_from_bandwidth(
f0norm, props->Equalizer.Mid2Width
)
);
gain = maxf(sqrtf(props->Equalizer.HighGain), 0.0625f);
f0norm = props->Equalizer.HighCutoff/frequency;
ALfilterState_setParams(&state->Chans[0].filter[3], ALfilterType_HighShelf,
gain, f0norm, calc_rcpQ_from_slope(gain, 0.75f)
);
/* Copy the filter coefficients for the other input channels. */
for(i = 1;i < MAX_EFFECT_CHANNELS;i++)
{
ALfilterState_copyParams(&state->Chans[i].filter[0], &state->Chans[0].filter[0]);
ALfilterState_copyParams(&state->Chans[i].filter[1], &state->Chans[0].filter[1]);
ALfilterState_copyParams(&state->Chans[i].filter[2], &state->Chans[0].filter[2]);
ALfilterState_copyParams(&state->Chans[i].filter[3], &state->Chans[0].filter[3]);
}
}
static ALvoid ALequalizerState_process(ALequalizerState *state, ALsizei SamplesToDo, const ALfloat (*restrict SamplesIn)[BUFFERSIZE], ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALsizei NumChannels)
{
ALfloat (*restrict temps)[BUFFERSIZE] = state->SampleBuffer;
ALsizei c;
for(c = 0;c < MAX_EFFECT_CHANNELS;c++)
{
ALfilterState_process(&state->Chans[c].filter[0], temps[0], SamplesIn[c], SamplesToDo);
ALfilterState_process(&state->Chans[c].filter[1], temps[1], temps[0], SamplesToDo);
ALfilterState_process(&state->Chans[c].filter[2], temps[2], temps[1], SamplesToDo);
ALfilterState_process(&state->Chans[c].filter[3], temps[3], temps[2], SamplesToDo);
MixSamples(temps[3], NumChannels, SamplesOut,
state->Chans[c].CurrentGains, state->Chans[c].TargetGains,
SamplesToDo, 0, SamplesToDo
);
}
}
typedef struct EqualizerStateFactory {
DERIVE_FROM_TYPE(EffectStateFactory);
} EqualizerStateFactory;
ALeffectState *EqualizerStateFactory_create(EqualizerStateFactory *UNUSED(factory))
{
ALequalizerState *state;
NEW_OBJ0(state, ALequalizerState)();
if(!state) return NULL;
return STATIC_CAST(ALeffectState, state);
}
DEFINE_EFFECTSTATEFACTORY_VTABLE(EqualizerStateFactory);
EffectStateFactory *EqualizerStateFactory_getFactory(void)
{
static EqualizerStateFactory EqualizerFactory = { { GET_VTABLE2(EqualizerStateFactory, EffectStateFactory) } };
return STATIC_CAST(EffectStateFactory, &EqualizerFactory);
}
void ALequalizer_setParami(ALeffect *UNUSED(effect), ALCcontext *context, ALenum param, ALint UNUSED(val))
{ alSetError(context, AL_INVALID_ENUM, "Invalid equalizer integer property 0x%04x", param); }
void ALequalizer_setParamiv(ALeffect *UNUSED(effect), ALCcontext *context, ALenum param, const ALint *UNUSED(vals))
{ alSetError(context, AL_INVALID_ENUM, "Invalid equalizer integer-vector property 0x%04x", param); }
void ALequalizer_setParamf(ALeffect *effect, ALCcontext *context, ALenum param, ALfloat val)
{
ALeffectProps *props = &effect->Props;
switch(param)
{
case AL_EQUALIZER_LOW_GAIN:
if(!(val >= AL_EQUALIZER_MIN_LOW_GAIN && val <= AL_EQUALIZER_MAX_LOW_GAIN))
SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer low-band gain out of range");
props->Equalizer.LowGain = val;
break;
case AL_EQUALIZER_LOW_CUTOFF:
if(!(val >= AL_EQUALIZER_MIN_LOW_CUTOFF && val <= AL_EQUALIZER_MAX_LOW_CUTOFF))
SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer low-band cutoff out of range");
props->Equalizer.LowCutoff = val;
break;
case AL_EQUALIZER_MID1_GAIN:
if(!(val >= AL_EQUALIZER_MIN_MID1_GAIN && val <= AL_EQUALIZER_MAX_MID1_GAIN))
SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid1-band gain out of range");
props->Equalizer.Mid1Gain = val;
break;
case AL_EQUALIZER_MID1_CENTER:
if(!(val >= AL_EQUALIZER_MIN_MID1_CENTER && val <= AL_EQUALIZER_MAX_MID1_CENTER))
SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid1-band center out of range");
props->Equalizer.Mid1Center = val;
break;
case AL_EQUALIZER_MID1_WIDTH:
if(!(val >= AL_EQUALIZER_MIN_MID1_WIDTH && val <= AL_EQUALIZER_MAX_MID1_WIDTH))
SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid1-band width out of range");
props->Equalizer.Mid1Width = val;
break;
case AL_EQUALIZER_MID2_GAIN:
if(!(val >= AL_EQUALIZER_MIN_MID2_GAIN && val <= AL_EQUALIZER_MAX_MID2_GAIN))
SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid2-band gain out of range");
props->Equalizer.Mid2Gain = val;
break;
case AL_EQUALIZER_MID2_CENTER:
if(!(val >= AL_EQUALIZER_MIN_MID2_CENTER && val <= AL_EQUALIZER_MAX_MID2_CENTER))
SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid2-band center out of range");
props->Equalizer.Mid2Center = val;
break;
case AL_EQUALIZER_MID2_WIDTH:
if(!(val >= AL_EQUALIZER_MIN_MID2_WIDTH && val <= AL_EQUALIZER_MAX_MID2_WIDTH))
SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer mid2-band width out of range");
props->Equalizer.Mid2Width = val;
break;
case AL_EQUALIZER_HIGH_GAIN:
if(!(val >= AL_EQUALIZER_MIN_HIGH_GAIN && val <= AL_EQUALIZER_MAX_HIGH_GAIN))
SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer high-band gain out of range");
props->Equalizer.HighGain = val;
break;
case AL_EQUALIZER_HIGH_CUTOFF:
if(!(val >= AL_EQUALIZER_MIN_HIGH_CUTOFF && val <= AL_EQUALIZER_MAX_HIGH_CUTOFF))
SETERR_RETURN(context, AL_INVALID_VALUE,, "Equalizer high-band cutoff out of range");
props->Equalizer.HighCutoff = val;
break;
default:
alSetError(context, AL_INVALID_ENUM, "Invalid equalizer float property 0x%04x", param);
}
}
void ALequalizer_setParamfv(ALeffect *effect, ALCcontext *context, ALenum param, const ALfloat *vals)
{ ALequalizer_setParamf(effect, context, param, vals[0]); }
void ALequalizer_getParami(const ALeffect *UNUSED(effect), ALCcontext *context, ALenum param, ALint *UNUSED(val))
{ alSetError(context, AL_INVALID_ENUM, "Invalid equalizer integer property 0x%04x", param); }
void ALequalizer_getParamiv(const ALeffect *UNUSED(effect), ALCcontext *context, ALenum param, ALint *UNUSED(vals))
{ alSetError(context, AL_INVALID_ENUM, "Invalid equalizer integer-vector property 0x%04x", param); }
void ALequalizer_getParamf(const ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *val)
{
const ALeffectProps *props = &effect->Props;
switch(param)
{
case AL_EQUALIZER_LOW_GAIN:
*val = props->Equalizer.LowGain;
break;
case AL_EQUALIZER_LOW_CUTOFF:
*val = props->Equalizer.LowCutoff;
break;
case AL_EQUALIZER_MID1_GAIN:
*val = props->Equalizer.Mid1Gain;
break;
case AL_EQUALIZER_MID1_CENTER:
*val = props->Equalizer.Mid1Center;
break;
case AL_EQUALIZER_MID1_WIDTH:
*val = props->Equalizer.Mid1Width;
break;
case AL_EQUALIZER_MID2_GAIN:
*val = props->Equalizer.Mid2Gain;
break;
case AL_EQUALIZER_MID2_CENTER:
*val = props->Equalizer.Mid2Center;
break;
case AL_EQUALIZER_MID2_WIDTH:
*val = props->Equalizer.Mid2Width;
break;
case AL_EQUALIZER_HIGH_GAIN:
*val = props->Equalizer.HighGain;
break;
case AL_EQUALIZER_HIGH_CUTOFF:
*val = props->Equalizer.HighCutoff;
break;
default:
alSetError(context, AL_INVALID_ENUM, "Invalid equalizer float property 0x%04x", param);
}
}
void ALequalizer_getParamfv(const ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *vals)
{ ALequalizer_getParamf(effect, context, param, vals); }
DEFINE_ALEFFECT_VTABLE(ALequalizer);