/**
* OpenAL cross platform audio library
* Copyright (C) 2013 by Anis A. Hireche
* 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 <stdlib.h>
#include "config.h"
#include "alError.h"
#include "alMain.h"
#include "alAuxEffectSlot.h"
#include "alu.h"
typedef struct ALcompressorState {
DERIVE_FROM_TYPE(ALeffectState);
/* Effect gains for each channel */
ALfloat Gain[MAX_EFFECT_CHANNELS][MAX_OUTPUT_CHANNELS];
/* Effect parameters */
ALboolean Enabled;
ALfloat AttackRate;
ALfloat ReleaseRate;
ALfloat GainCtrl;
} ALcompressorState;
static ALvoid ALcompressorState_Destruct(ALcompressorState *state)
{
ALeffectState_Destruct(STATIC_CAST(ALeffectState,state));
}
static ALboolean ALcompressorState_deviceUpdate(ALcompressorState *state, ALCdevice *device)
{
const ALfloat attackTime = device->Frequency * 0.2f; /* 200ms Attack */
const ALfloat releaseTime = device->Frequency * 0.4f; /* 400ms Release */
state->AttackRate = 1.0f / attackTime;
state->ReleaseRate = 1.0f / releaseTime;
return AL_TRUE;
}
static ALvoid ALcompressorState_update(ALcompressorState *state, const ALCdevice *device, const ALeffectslot *slot, const ALeffectProps *props)
{
aluMatrixf matrix;
ALuint i;
state->Enabled = props->Compressor.OnOff;
aluMatrixfSet(&matrix,
1.0f, 0.0f, 0.0f, 0.0f,
0.0f, 1.0f, 0.0f, 0.0f,
0.0f, 0.0f, 1.0f, 0.0f,
0.0f, 0.0f, 0.0f, 1.0f
);
STATIC_CAST(ALeffectState,state)->OutBuffer = device->FOAOut.Buffer;
STATIC_CAST(ALeffectState,state)->OutChannels = device->FOAOut.NumChannels;
for(i = 0;i < 4;i++)
ComputeFirstOrderGains(device->FOAOut, matrix.m[i], slot->Params.Gain,
state->Gain[i]);
}
static ALvoid ALcompressorState_process(ALcompressorState *state, ALuint SamplesToDo, const ALfloat (*restrict SamplesIn)[BUFFERSIZE], ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALuint NumChannels)
{
ALuint i, j, k;
ALuint base;
for(base = 0;base < SamplesToDo;)
{
ALfloat temps[64][4];
ALuint td = minu(64, SamplesToDo-base);
/* Load samples into the temp buffer first. */
for(j = 0;j < 4;j++)
{
for(i = 0;i < td;i++)
temps[i][j] = SamplesIn[j][i+base];
}
if(state->Enabled)
{
ALfloat gain = state->GainCtrl;
ALfloat output, amplitude;
for(i = 0;i < td;i++)
{
/* Roughly calculate the maximum amplitude from the 4-channel
* signal, and attack or release the gain control to reach it.
*/
amplitude = fabsf(temps[i][0]);
amplitude = maxf(amplitude + fabsf(temps[i][1]),
maxf(amplitude + fabsf(temps[i][2]),
amplitude + fabsf(temps[i][3])));
if(amplitude > gain)
gain = minf(gain+state->AttackRate, amplitude);
else if(amplitude < gain)
gain = maxf(gain-state->ReleaseRate, amplitude);
/* Apply the inverse of the gain control to normalize/compress
* the volume. */
output = 1.0f / clampf(gain, 0.5f, 2.0f);
for(j = 0;j < 4;j++)
temps[i][j] *= output;
}
state->GainCtrl = gain;
}
else
{
ALfloat gain = state->GainCtrl;
ALfloat output, amplitude;
for(i = 0;i < td;i++)
{
/* Same as above, except the amplitude is forced to 1. This
* helps ensure smooth gain changes when the compressor is
* turned on and off.
*/
amplitude = 1.0f;
if(amplitude > gain)
gain = minf(gain+state->AttackRate, amplitude);
else if(amplitude < gain)
gain = maxf(gain-state->ReleaseRate, amplitude);
output = 1.0f / clampf(gain, 0.5f, 2.0f);
for(j = 0;j < 4;j++)
temps[i][j] *= output;
}
state->GainCtrl = gain;
}
/* Now mix to the output. */
for(j = 0;j < 4;j++)
{
for(k = 0;k < NumChannels;k++)
{
ALfloat gain = state->Gain[j][k];
if(!(fabsf(gain) > GAIN_SILENCE_THRESHOLD))
continue;
for(i = 0;i < td;i++)
SamplesOut[k][base+i] += gain * temps[i][j];
}
}
base += td;
}
}
DECLARE_DEFAULT_ALLOCATORS(ALcompressorState)
DEFINE_ALEFFECTSTATE_VTABLE(ALcompressorState);
typedef struct ALcompressorStateFactory {
DERIVE_FROM_TYPE(ALeffectStateFactory);
} ALcompressorStateFactory;
static ALeffectState *ALcompressorStateFactory_create(ALcompressorStateFactory *UNUSED(factory))
{
ALcompressorState *state;
state = ALcompressorState_New(sizeof(*state));
if(!state) return NULL;
SET_VTABLE2(ALcompressorState, ALeffectState, state);
state->Enabled = AL_TRUE;
state->AttackRate = 0.0f;
state->ReleaseRate = 0.0f;
state->GainCtrl = 1.0f;
return STATIC_CAST(ALeffectState, state);
}
DEFINE_ALEFFECTSTATEFACTORY_VTABLE(ALcompressorStateFactory);
ALeffectStateFactory *ALcompressorStateFactory_getFactory(void)
{
static ALcompressorStateFactory CompressorFactory = { { GET_VTABLE2(ALcompressorStateFactory, ALeffectStateFactory) } };
return STATIC_CAST(ALeffectStateFactory, &CompressorFactory);
}
void ALcompressor_setParami(ALeffect *effect, ALCcontext *context, ALenum param, ALint val)
{
ALeffectProps *props = &effect->Props;
switch(param)
{
case AL_COMPRESSOR_ONOFF:
if(!(val >= AL_COMPRESSOR_MIN_ONOFF && val <= AL_COMPRESSOR_MAX_ONOFF))
SET_ERROR_AND_RETURN(context, AL_INVALID_VALUE);
props->Compressor.OnOff = val;
break;
default:
SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM);
}
}
void ALcompressor_setParamiv(ALeffect *effect, ALCcontext *context, ALenum param, const ALint *vals)
{
ALcompressor_setParami(effect, context, param, vals[0]);
}
void ALcompressor_setParamf(ALeffect *UNUSED(effect), ALCcontext *context, ALenum UNUSED(param), ALfloat UNUSED(val))
{ SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM); }
void ALcompressor_setParamfv(ALeffect *effect, ALCcontext *context, ALenum param, const ALfloat *vals)
{
ALcompressor_setParamf(effect, context, param, vals[0]);
}
void ALcompressor_getParami(const ALeffect *effect, ALCcontext *context, ALenum param, ALint *val)
{
const ALeffectProps *props = &effect->Props;
switch(param)
{
case AL_COMPRESSOR_ONOFF:
*val = props->Compressor.OnOff;
break;
default:
SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM);
}
}
void ALcompressor_getParamiv(const ALeffect *effect, ALCcontext *context, ALenum param, ALint *vals)
{
ALcompressor_getParami(effect, context, param, vals);
}
void ALcompressor_getParamf(const ALeffect *UNUSED(effect), ALCcontext *context, ALenum UNUSED(param), ALfloat *UNUSED(val))
{ SET_ERROR_AND_RETURN(context, AL_INVALID_ENUM); }
void ALcompressor_getParamfv(const ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *vals)
{
ALcompressor_getParamf(effect, context, param, vals);
}
DEFINE_ALEFFECT_VTABLE(ALcompressor);