301 lines
10 KiB
C
301 lines
10 KiB
C
/**
|
|
* 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 ALdistortionState {
|
|
DERIVE_FROM_TYPE(ALeffectState);
|
|
|
|
/* Effect gains for each channel */
|
|
ALfloat Gain[MaxChannels];
|
|
|
|
/* Effect parameters */
|
|
ALfilterState lowpass;
|
|
ALfilterState bandpass;
|
|
ALfloat attenuation;
|
|
ALfloat edge_coeff;
|
|
} ALdistortionState;
|
|
|
|
static ALvoid ALdistortionState_Destruct(ALdistortionState *UNUSED(state))
|
|
{
|
|
}
|
|
|
|
static ALboolean ALdistortionState_deviceUpdate(ALdistortionState *UNUSED(state), ALCdevice *UNUSED(device))
|
|
{
|
|
return AL_TRUE;
|
|
}
|
|
|
|
static ALvoid ALdistortionState_update(ALdistortionState *state, ALCdevice *Device, const ALeffectslot *Slot)
|
|
{
|
|
ALfloat frequency = (ALfloat)Device->Frequency;
|
|
ALfloat bandwidth;
|
|
ALfloat cutoff;
|
|
ALfloat edge;
|
|
ALfloat gain;
|
|
|
|
/* Store distorted signal attenuation settings */
|
|
state->attenuation = Slot->EffectProps.Distortion.Gain;
|
|
|
|
/* Store waveshaper edge settings */
|
|
edge = sinf(Slot->EffectProps.Distortion.Edge * (F_PI_2));
|
|
edge = minf(edge, 0.99f);
|
|
state->edge_coeff = 2.0f * edge / (1.0f-edge);
|
|
|
|
/* Lowpass filter */
|
|
cutoff = Slot->EffectProps.Distortion.LowpassCutoff;
|
|
/* Bandwidth value is constant in octaves */
|
|
bandwidth = (cutoff / 2.0f) / (cutoff * 0.67f);
|
|
ALfilterState_setParams(&state->lowpass, ALfilterType_LowPass, 1.0f,
|
|
cutoff / (frequency*4.0f), bandwidth);
|
|
|
|
/* Bandpass filter */
|
|
cutoff = Slot->EffectProps.Distortion.EQCenter;
|
|
/* Convert bandwidth in Hz to octaves */
|
|
bandwidth = Slot->EffectProps.Distortion.EQBandwidth / (cutoff * 0.67f);
|
|
ALfilterState_setParams(&state->bandpass, ALfilterType_BandPass, 1.0f,
|
|
cutoff / (frequency*4.0f), bandwidth);
|
|
|
|
gain = sqrtf(1.0f / Device->NumChan) * Slot->Gain;
|
|
SetGains(Device, gain, state->Gain);
|
|
}
|
|
|
|
static ALvoid ALdistortionState_process(ALdistortionState *state, ALuint SamplesToDo, const ALfloat *restrict SamplesIn, ALfloat (*restrict SamplesOut)[BUFFERSIZE])
|
|
{
|
|
const ALfloat fc = state->edge_coeff;
|
|
float oversample_buffer[64][4];
|
|
ALuint base;
|
|
ALuint it;
|
|
ALuint ot;
|
|
ALuint kt;
|
|
|
|
for(base = 0;base < SamplesToDo;)
|
|
{
|
|
ALfloat temps[64];
|
|
ALuint td = minu(SamplesToDo-base, 64);
|
|
|
|
/* Perform 4x oversampling to avoid aliasing. */
|
|
/* Oversampling greatly improves distortion */
|
|
/* quality and allows to implement lowpass and */
|
|
/* bandpass filters using high frequencies, at */
|
|
/* which classic IIR filters became unstable. */
|
|
|
|
/* Fill oversample buffer using zero stuffing */
|
|
for(it = 0;it < td;it++)
|
|
{
|
|
oversample_buffer[it][0] = SamplesIn[it+base];
|
|
oversample_buffer[it][1] = 0.0f;
|
|
oversample_buffer[it][2] = 0.0f;
|
|
oversample_buffer[it][3] = 0.0f;
|
|
}
|
|
|
|
/* First step, do lowpass filtering of original signal, */
|
|
/* additionally perform buffer interpolation and lowpass */
|
|
/* cutoff for oversampling (which is fortunately first */
|
|
/* step of distortion). So combine three operations into */
|
|
/* the one. */
|
|
for(it = 0;it < td;it++)
|
|
{
|
|
for(ot = 0;ot < 4;ot++)
|
|
{
|
|
ALfloat smp;
|
|
smp = ALfilterState_processSingle(&state->lowpass, oversample_buffer[it][ot]);
|
|
|
|
/* Restore signal power by multiplying sample by amount of oversampling */
|
|
oversample_buffer[it][ot] = smp * 4.0f;
|
|
}
|
|
}
|
|
|
|
for(it = 0;it < td;it++)
|
|
{
|
|
/* Second step, do distortion using waveshaper function */
|
|
/* to emulate signal processing during tube overdriving. */
|
|
/* Three steps of waveshaping are intended to modify */
|
|
/* waveform without boost/clipping/attenuation process. */
|
|
for(ot = 0;ot < 4;ot++)
|
|
{
|
|
ALfloat smp = oversample_buffer[it][ot];
|
|
|
|
smp = (1.0f + fc) * smp/(1.0f + fc*fabsf(smp));
|
|
smp = (1.0f + fc) * smp/(1.0f + fc*fabsf(smp)) * -1.0f;
|
|
smp = (1.0f + fc) * smp/(1.0f + fc*fabsf(smp));
|
|
|
|
/* Third step, do bandpass filtering of distorted signal */
|
|
smp = ALfilterState_processSingle(&state->bandpass, smp);
|
|
oversample_buffer[it][ot] = smp;
|
|
}
|
|
|
|
/* Fourth step, final, do attenuation and perform decimation, */
|
|
/* store only one sample out of 4. */
|
|
temps[it] = oversample_buffer[it][0] * state->attenuation;
|
|
}
|
|
|
|
for(kt = 0;kt < MaxChannels;kt++)
|
|
{
|
|
ALfloat gain = state->Gain[kt];
|
|
if(!(gain > GAIN_SILENCE_THRESHOLD))
|
|
continue;
|
|
|
|
for(it = 0;it < td;it++)
|
|
SamplesOut[kt][base+it] += gain * temps[it];
|
|
}
|
|
|
|
base += td;
|
|
}
|
|
}
|
|
|
|
static void ALdistortionState_Delete(ALdistortionState *state)
|
|
{
|
|
free(state);
|
|
}
|
|
|
|
DEFINE_ALEFFECTSTATE_VTABLE(ALdistortionState);
|
|
|
|
|
|
typedef struct ALdistortionStateFactory {
|
|
DERIVE_FROM_TYPE(ALeffectStateFactory);
|
|
} ALdistortionStateFactory;
|
|
|
|
static ALeffectState *ALdistortionStateFactory_create(ALdistortionStateFactory *UNUSED(factory))
|
|
{
|
|
ALdistortionState *state;
|
|
|
|
state = malloc(sizeof(*state));
|
|
if(!state) return NULL;
|
|
SET_VTABLE2(ALdistortionState, ALeffectState, state);
|
|
|
|
ALfilterState_clear(&state->lowpass);
|
|
ALfilterState_clear(&state->bandpass);
|
|
|
|
return STATIC_CAST(ALeffectState, state);
|
|
}
|
|
|
|
DEFINE_ALEFFECTSTATEFACTORY_VTABLE(ALdistortionStateFactory);
|
|
|
|
|
|
ALeffectStateFactory *ALdistortionStateFactory_getFactory(void)
|
|
{
|
|
static ALdistortionStateFactory DistortionFactory = { { GET_VTABLE2(ALdistortionStateFactory, ALeffectStateFactory) } };
|
|
|
|
return STATIC_CAST(ALeffectStateFactory, &DistortionFactory);
|
|
}
|
|
|
|
|
|
void ALdistortion_setParami(ALeffect *UNUSED(effect), ALCcontext *context, ALenum UNUSED(param), ALint UNUSED(val))
|
|
{ SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM); }
|
|
void ALdistortion_setParamiv(ALeffect *effect, ALCcontext *context, ALenum param, const ALint *vals)
|
|
{
|
|
ALdistortion_setParami(effect, context, param, vals[0]);
|
|
}
|
|
void ALdistortion_setParamf(ALeffect *effect, ALCcontext *context, ALenum param, ALfloat val)
|
|
{
|
|
ALeffectProps *props = &effect->Props;
|
|
switch(param)
|
|
{
|
|
case AL_DISTORTION_EDGE:
|
|
if(!(val >= AL_DISTORTION_MIN_EDGE && val <= AL_DISTORTION_MAX_EDGE))
|
|
SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
|
|
props->Distortion.Edge = val;
|
|
break;
|
|
|
|
case AL_DISTORTION_GAIN:
|
|
if(!(val >= AL_DISTORTION_MIN_GAIN && val <= AL_DISTORTION_MAX_GAIN))
|
|
SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
|
|
props->Distortion.Gain = val;
|
|
break;
|
|
|
|
case AL_DISTORTION_LOWPASS_CUTOFF:
|
|
if(!(val >= AL_DISTORTION_MIN_LOWPASS_CUTOFF && val <= AL_DISTORTION_MAX_LOWPASS_CUTOFF))
|
|
SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
|
|
props->Distortion.LowpassCutoff = val;
|
|
break;
|
|
|
|
case AL_DISTORTION_EQCENTER:
|
|
if(!(val >= AL_DISTORTION_MIN_EQCENTER && val <= AL_DISTORTION_MAX_EQCENTER))
|
|
SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
|
|
props->Distortion.EQCenter = val;
|
|
break;
|
|
|
|
case AL_DISTORTION_EQBANDWIDTH:
|
|
if(!(val >= AL_DISTORTION_MIN_EQBANDWIDTH && val <= AL_DISTORTION_MAX_EQBANDWIDTH))
|
|
SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
|
|
props->Distortion.EQBandwidth = val;
|
|
break;
|
|
|
|
default:
|
|
SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM);
|
|
}
|
|
}
|
|
void ALdistortion_setParamfv(ALeffect *effect, ALCcontext *context, ALenum param, const ALfloat *vals)
|
|
{
|
|
ALdistortion_setParamf(effect, context, param, vals[0]);
|
|
}
|
|
|
|
void ALdistortion_getParami(const ALeffect *UNUSED(effect), ALCcontext *context, ALenum UNUSED(param), ALint *UNUSED(val))
|
|
{ SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM); }
|
|
void ALdistortion_getParamiv(const ALeffect *effect, ALCcontext *context, ALenum param, ALint *vals)
|
|
{
|
|
ALdistortion_getParami(effect, context, param, vals);
|
|
}
|
|
void ALdistortion_getParamf(const ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *val)
|
|
{
|
|
const ALeffectProps *props = &effect->Props;
|
|
switch(param)
|
|
{
|
|
case AL_DISTORTION_EDGE:
|
|
*val = props->Distortion.Edge;
|
|
break;
|
|
|
|
case AL_DISTORTION_GAIN:
|
|
*val = props->Distortion.Gain;
|
|
break;
|
|
|
|
case AL_DISTORTION_LOWPASS_CUTOFF:
|
|
*val = props->Distortion.LowpassCutoff;
|
|
break;
|
|
|
|
case AL_DISTORTION_EQCENTER:
|
|
*val = props->Distortion.EQCenter;
|
|
break;
|
|
|
|
case AL_DISTORTION_EQBANDWIDTH:
|
|
*val = props->Distortion.EQBandwidth;
|
|
break;
|
|
|
|
default:
|
|
SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM);
|
|
}
|
|
}
|
|
void ALdistortion_getParamfv(const ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *vals)
|
|
{
|
|
ALdistortion_getParamf(effect, context, param, vals);
|
|
}
|
|
|
|
DEFINE_ALEFFECT_VTABLE(ALdistortion);
|