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/**
* 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., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, 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[MaxChannels];
/* Effect parameters */
ALboolean Enabled;
ALfloat Envelope;
ALfloat EnvGain;
ALfloat Attack;
ALfloat Release;
} ALcompressorState;
static ALvoid ALcompressorState_Destruct(ALcompressorState *UNUSED(state))
{
}
static ALboolean ALcompressorState_deviceUpdate(ALcompressorState *state, ALCdevice *device)
{
state->Attack = expf(-1.0f / (device->Frequency * 0.0001f));
state->Release = expf(-1.0f / (device->Frequency * 0.3f));
state->Envelope = 0.0f;
state->EnvGain = 1.0f;
return AL_TRUE;
}
static ALvoid ALcompressorState_update(ALcompressorState *state, ALCdevice *Device, const ALeffectslot *Slot)
{
ALfloat gain;
state->Enabled = Slot->EffectProps.Compressor.OnOff;
/* FIXME: Could maybe use the compressor's attack/release to move the gain to 1? */
if(!state->Enabled)
state->EnvGain = 1.0f;
gain = sqrtf(1.0f / Device->NumChan) * Slot->Gain;
SetGains(Device, gain, state->Gain);
}
static ALvoid ALcompressorState_process(ALcompressorState *state, ALuint SamplesToDo, const ALfloat *SamplesIn, ALfloat (*SamplesOut)[BUFFERSIZE])
{
ALfloat env = state->Envelope;
ALfloat envgain = state->EnvGain;
ALfloat tattack = state->Attack;
ALfloat trelease = state->Release;
ALuint it, kt;
ALuint base;
ALfloat theta;
ALfloat rms;
for(base = 0;base < SamplesToDo;)
{
ALfloat temps[64];
ALuint td = minu(SamplesToDo-base, 64);
ALfloat summ = 0.0f;
for(it = 0;it < td;it++)
{
ALfloat smp = SamplesIn[it+base] * 0.5f;
summ += smp * smp;
temps[it] = smp;
}
if(state->Enabled)
{
const ALfloat threshold = 0.5f;
const ALfloat slope = 0.5f;
/* computing rms and envelope */
rms = sqrtf(summ / td);
theta = ((rms > env) ? tattack : trelease);
env = (1.0f - theta)*rms + theta*env;
/* applying a hard-knee rms based compressor */
if(env > threshold)
envgain = envgain - (env - threshold) * slope;
}
for(kt = 0;kt < MaxChannels;kt++)
{
ALfloat gain = state->Gain[kt] * envgain * 2.0f;
if(!(gain > GAIN_SILENCE_THRESHOLD))
continue;
for(it = 0;it < td;it++)
SamplesOut[kt][base+it] += gain * temps[it];
}
base += td;
}
state->Envelope = env;
state->EnvGain = envgain;
}
static void ALcompressorState_Delete(ALcompressorState *state)
{
free(state);
}
DEFINE_ALEFFECTSTATE_VTABLE(ALcompressorState);
typedef struct ALcompressorStateFactory {
DERIVE_FROM_TYPE(ALeffectStateFactory);
} ALcompressorStateFactory;
static ALeffectState *ALcompressorStateFactory_create(ALcompressorStateFactory *UNUSED(factory))
{
ALcompressorState *state;
state = malloc(sizeof(*state));
if(!state) return NULL;
SET_VTABLE2(ALcompressorState, ALeffectState, state);
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);
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