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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.,
* 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"
#define AMP_ENVELOPE_MIN 0.5f
#define AMP_ENVELOPE_MAX 2.0f
#define ATTACK_TIME 0.1f /* 100ms to rise from min to max */
#define RELEASE_TIME 0.2f /* 200ms to drop from max to min */
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 AttackMult;
ALfloat ReleaseMult;
ALfloat EnvFollower;
} ALcompressorState;
static ALvoid ALcompressorState_Destruct(ALcompressorState *state);
static ALboolean ALcompressorState_deviceUpdate(ALcompressorState *state, ALCdevice *device);
static ALvoid ALcompressorState_update(ALcompressorState *state, const ALCcontext *context, const ALeffectslot *slot, const ALeffectProps *props);
static ALvoid ALcompressorState_process(ALcompressorState *state, ALsizei SamplesToDo, const ALfloat (*restrict SamplesIn)[BUFFERSIZE], ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALsizei NumChannels);
DECLARE_DEFAULT_ALLOCATORS(ALcompressorState)
DEFINE_ALEFFECTSTATE_VTABLE(ALcompressorState);
static void ALcompressorState_Construct(ALcompressorState *state)
{
ALeffectState_Construct(STATIC_CAST(ALeffectState, state));
SET_VTABLE2(ALcompressorState, ALeffectState, state);
state->Enabled = AL_TRUE;
state->AttackMult = 1.0f;
state->ReleaseMult = 1.0f;
state->EnvFollower = 1.0f;
}
static ALvoid ALcompressorState_Destruct(ALcompressorState *state)
{
ALeffectState_Destruct(STATIC_CAST(ALeffectState,state));
}
static ALboolean ALcompressorState_deviceUpdate(ALcompressorState *state, ALCdevice *device)
{
/* Number of samples to do a full attack and release (non-integer sample
* counts are okay).
*/
const ALfloat attackCount = (ALfloat)device->Frequency * ATTACK_TIME;
const ALfloat releaseCount = (ALfloat)device->Frequency * RELEASE_TIME;
/* Calculate per-sample multipliers to attack and release at the desired
* rates.
*/
state->AttackMult = powf(AMP_ENVELOPE_MAX/AMP_ENVELOPE_MIN, 1.0f/attackCount);
state->ReleaseMult = powf(AMP_ENVELOPE_MIN/AMP_ENVELOPE_MAX, 1.0f/releaseCount);
return AL_TRUE;
}
static ALvoid ALcompressorState_update(ALcompressorState *state, const ALCcontext *context, const ALeffectslot *slot, const ALeffectProps *props)
{
const ALCdevice *device = context->Device;
ALuint i;
state->Enabled = props->Compressor.OnOff;
STATIC_CAST(ALeffectState,state)->OutBuffer = device->FOAOut.Buffer;
STATIC_CAST(ALeffectState,state)->OutChannels = device->FOAOut.NumChannels;
for(i = 0;i < 4;i++)
ComputePanGains(&device->FOAOut, IdentityMatrixf.m[i], slot->Params.Gain, state->Gain[i]);
}
static ALvoid ALcompressorState_process(ALcompressorState *state, ALsizei SamplesToDo, const ALfloat (*restrict SamplesIn)[BUFFERSIZE], ALfloat (*restrict SamplesOut)[BUFFERSIZE], ALsizei NumChannels)
{
ALsizei i, j, k;
ALsizei base;
for(base = 0;base < SamplesToDo;)
{
ALfloat gains[256];
ALsizei td = mini(256, SamplesToDo-base);
ALfloat env = state->EnvFollower;
/* Generate the per-sample gains from the signal envelope. */
if(state->Enabled)
{
for(i = 0;i < td;++i)
{
/* Clamp the absolute amplitude to the defined envelope limits,
* then attack or release the envelope to reach it.
*/
ALfloat amplitude = clampf(fabsf(SamplesIn[0][base+i]),
AMP_ENVELOPE_MIN, AMP_ENVELOPE_MAX);
if(amplitude > env)
env = minf(env*state->AttackMult, amplitude);
else if(amplitude < env)
env = maxf(env*state->ReleaseMult, amplitude);
/* Apply the reciprocal of the envelope to normalize the volume
* (compress the dynamic range).
*/
gains[i] = 1.0f / env;
}
}
else
{
/* Same as above, except the amplitude is forced to 1. This helps
* ensure smooth gain changes when the compressor is turned on and
* off.
*/
for(i = 0;i < td;++i)
{
ALfloat amplitude = 1.0f;
if(amplitude > env)
env = minf(env*state->AttackMult, amplitude);
else if(amplitude < env)
env = maxf(env*state->ReleaseMult, amplitude);
gains[i] = 1.0f / env;
}
}
state->EnvFollower = env;
/* Now compress the signal amplitude to output. */
for(j = 0;j < MAX_EFFECT_CHANNELS;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] += SamplesIn[j][base+i] * gains[i] * gain;
}
}
base += td;
}
}
typedef struct CompressorStateFactory {
DERIVE_FROM_TYPE(EffectStateFactory);
} CompressorStateFactory;
static ALeffectState *CompressorStateFactory_create(CompressorStateFactory *UNUSED(factory))
{
ALcompressorState *state;
NEW_OBJ0(state, ALcompressorState)();
if(!state) return NULL;
return STATIC_CAST(ALeffectState, state);
}
DEFINE_EFFECTSTATEFACTORY_VTABLE(CompressorStateFactory);
EffectStateFactory *CompressorStateFactory_getFactory(void)
{
static CompressorStateFactory CompressorFactory = { { GET_VTABLE2(CompressorStateFactory, EffectStateFactory) } };
return STATIC_CAST(EffectStateFactory, &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))
SETERR_RETURN(context, AL_INVALID_VALUE,, "Compressor state out of range");
props->Compressor.OnOff = val;
break;
default:
alSetError(context, AL_INVALID_ENUM, "Invalid compressor integer property 0x%04x",
param);
}
}
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 param, ALfloat UNUSED(val))
{ alSetError(context, AL_INVALID_ENUM, "Invalid compressor float property 0x%04x", param); }
void ALcompressor_setParamfv(ALeffect *UNUSED(effect), ALCcontext *context, ALenum param, const ALfloat *UNUSED(vals))
{ alSetError(context, AL_INVALID_ENUM, "Invalid compressor float-vector property 0x%04x", param); }
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:
alSetError(context, AL_INVALID_ENUM, "Invalid compressor integer property 0x%04x",
param);
}
}
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 param, ALfloat *UNUSED(val))
{ alSetError(context, AL_INVALID_ENUM, "Invalid compressor float property 0x%04x", param); }
void ALcompressor_getParamfv(const ALeffect *UNUSED(effect), ALCcontext *context, ALenum param, ALfloat *UNUSED(vals))
{ alSetError(context, AL_INVALID_ENUM, "Invalid compressor float-vector property 0x%04x", param); }
DEFINE_ALEFFECT_VTABLE(ALcompressor);
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