/**
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* OpenAL cross platform audio library
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* Copyright (C) 2013 by Anis A. Hireche
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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* Or go to http://www.gnu.org/copyleft/lgpl.html
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*/
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#include "config.h"
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#include <cstdlib>
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#include "alMain.h"
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#include "alcontext.h"
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#include "alu.h"
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#include "alAuxEffectSlot.h"
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#include "alError.h"
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#include "vecmat.h"
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namespace {
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#define AMP_ENVELOPE_MIN 0.5f
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#define AMP_ENVELOPE_MAX 2.0f
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#define ATTACK_TIME 0.1f /* 100ms to rise from min to max */
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#define RELEASE_TIME 0.2f /* 200ms to drop from max to min */
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struct CompressorState final : public EffectState {
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/* Effect gains for each channel */
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ALfloat mGain[MAX_AMBI_CHANNELS][MAX_OUTPUT_CHANNELS]{};
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/* Effect parameters */
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ALboolean mEnabled{AL_TRUE};
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ALfloat mAttackMult{1.0f};
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ALfloat mReleaseMult{1.0f};
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ALfloat mEnvFollower{1.0f};
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ALboolean deviceUpdate(const ALCdevice *device) override;
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void update(const ALCcontext *context, const ALeffectslot *slot, const EffectProps *props, const EffectTarget target) override;
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void process(ALsizei samplesToDo, const ALfloat (*RESTRICT samplesIn)[BUFFERSIZE], const ALsizei numInput, ALfloat (*RESTRICT samplesOut)[BUFFERSIZE], const ALsizei numOutput) override;
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DEF_NEWDEL(CompressorState)
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};
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ALboolean CompressorState::deviceUpdate(const ALCdevice *device)
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{
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/* Number of samples to do a full attack and release (non-integer sample
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* counts are okay).
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*/
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const ALfloat attackCount = static_cast<ALfloat>(device->Frequency) * ATTACK_TIME;
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const ALfloat releaseCount = static_cast<ALfloat>(device->Frequency) * RELEASE_TIME;
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/* Calculate per-sample multipliers to attack and release at the desired
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* rates.
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*/
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mAttackMult = std::pow(AMP_ENVELOPE_MAX/AMP_ENVELOPE_MIN, 1.0f/attackCount);
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mReleaseMult = std::pow(AMP_ENVELOPE_MIN/AMP_ENVELOPE_MAX, 1.0f/releaseCount);
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return AL_TRUE;
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}
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void CompressorState::update(const ALCcontext* UNUSED(context), const ALeffectslot *slot, const EffectProps *props, const EffectTarget target)
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{
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mEnabled = props->Compressor.OnOff;
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mOutBuffer = target.Main->Buffer;
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mOutChannels = target.Main->NumChannels;
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for(ALsizei i{0};i < slot->Wet.NumChannels;++i)
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{
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auto coeffs = GetAmbiIdentityRow(i);
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ComputePanGains(target.Main, coeffs.data(), slot->Params.Gain, mGain[i]);
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}
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}
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void CompressorState::process(ALsizei samplesToDo, const ALfloat (*RESTRICT samplesIn)[BUFFERSIZE], const ALsizei numInput, ALfloat (*RESTRICT samplesOut)[BUFFERSIZE], const ALsizei numOutput)
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{
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ALsizei i, j, k;
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ALsizei base;
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for(base = 0;base < samplesToDo;)
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{
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ALfloat gains[256];
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ALsizei td = mini(256, samplesToDo-base);
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ALfloat env = mEnvFollower;
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/* Generate the per-sample gains from the signal envelope. */
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if(mEnabled)
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{
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for(i = 0;i < td;++i)
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{
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/* Clamp the absolute amplitude to the defined envelope limits,
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* then attack or release the envelope to reach it.
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*/
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const ALfloat amplitude{clampf(std::fabs(samplesIn[0][base+i]), AMP_ENVELOPE_MIN,
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AMP_ENVELOPE_MAX)};
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if(amplitude > env)
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env = minf(env*mAttackMult, amplitude);
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else if(amplitude < env)
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env = maxf(env*mReleaseMult, amplitude);
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/* Apply the reciprocal of the envelope to normalize the volume
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* (compress the dynamic range).
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*/
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gains[i] = 1.0f / env;
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}
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}
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else
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{
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/* Same as above, except the amplitude is forced to 1. This helps
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* ensure smooth gain changes when the compressor is turned on and
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* off.
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*/
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for(i = 0;i < td;++i)
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{
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const ALfloat amplitude{1.0f};
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if(amplitude > env)
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env = minf(env*mAttackMult, amplitude);
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else if(amplitude < env)
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env = maxf(env*mReleaseMult, amplitude);
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gains[i] = 1.0f / env;
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}
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}
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mEnvFollower = env;
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/* Now compress the signal amplitude to output. */
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ASSUME(numInput > 0);
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for(j = 0;j < numInput;j++)
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{
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ASSUME(numOutput > 0);
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for(k = 0;k < numOutput;k++)
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{
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const ALfloat gain{mGain[j][k]};
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if(!(std::fabs(gain) > GAIN_SILENCE_THRESHOLD))
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continue;
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for(i = 0;i < td;i++)
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samplesOut[k][base+i] += samplesIn[j][base+i] * gains[i] * gain;
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}
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}
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base += td;
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}
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}
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void Compressor_setParami(EffectProps *props, ALCcontext *context, ALenum param, ALint val)
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{
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switch(param)
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{
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case AL_COMPRESSOR_ONOFF:
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if(!(val >= AL_COMPRESSOR_MIN_ONOFF && val <= AL_COMPRESSOR_MAX_ONOFF))
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SETERR_RETURN(context, AL_INVALID_VALUE,, "Compressor state out of range");
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props->Compressor.OnOff = val;
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break;
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default:
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alSetError(context, AL_INVALID_ENUM, "Invalid compressor integer property 0x%04x",
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param);
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}
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}
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void Compressor_setParamiv(EffectProps *props, ALCcontext *context, ALenum param, const ALint *vals)
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{ Compressor_setParami(props, context, param, vals[0]); }
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void Compressor_setParamf(EffectProps*, ALCcontext *context, ALenum param, ALfloat)
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{ alSetError(context, AL_INVALID_ENUM, "Invalid compressor float property 0x%04x", param); }
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void Compressor_setParamfv(EffectProps*, ALCcontext *context, ALenum param, const ALfloat*)
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{ alSetError(context, AL_INVALID_ENUM, "Invalid compressor float-vector property 0x%04x", param); }
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void Compressor_getParami(const EffectProps *props, ALCcontext *context, ALenum param, ALint *val)
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{
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switch(param)
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{
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case AL_COMPRESSOR_ONOFF:
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*val = props->Compressor.OnOff;
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break;
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default:
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alSetError(context, AL_INVALID_ENUM, "Invalid compressor integer property 0x%04x",
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param);
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}
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}
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void Compressor_getParamiv(const EffectProps *props, ALCcontext *context, ALenum param, ALint *vals)
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{ Compressor_getParami(props, context, param, vals); }
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void Compressor_getParamf(const EffectProps*, ALCcontext *context, ALenum param, ALfloat*)
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{ alSetError(context, AL_INVALID_ENUM, "Invalid compressor float property 0x%04x", param); }
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void Compressor_getParamfv(const EffectProps*, ALCcontext *context, ALenum param, ALfloat*)
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{ alSetError(context, AL_INVALID_ENUM, "Invalid compressor float-vector property 0x%04x", param); }
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DEFINE_ALEFFECT_VTABLE(Compressor);
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struct CompressorStateFactory final : public EffectStateFactory {
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EffectState *create() override { return new CompressorState{}; }
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EffectProps getDefaultProps() const noexcept override;
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const EffectVtable *getEffectVtable() const noexcept override { return &Compressor_vtable; }
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};
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EffectProps CompressorStateFactory::getDefaultProps() const noexcept
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{
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EffectProps props{};
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props.Compressor.OnOff = AL_COMPRESSOR_DEFAULT_ONOFF;
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return props;
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}
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} // namespace
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EffectStateFactory *CompressorStateFactory_getFactory()
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{
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static CompressorStateFactory CompressorFactory{};
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return &CompressorFactory;
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}
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