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/**
* This file is part of the OpenAL Soft cross platform audio library
*
* Copyright (C) 2013 by Anis A. Hireche
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* * Neither the name of Spherical-Harmonic-Transform nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include <array>
#include <cstdlib>
#include <iterator>
#include <utility>
#include "alc/effects/base.h"
#include "almalloc.h"
#include "alnumeric.h"
#include "alspan.h"
#include "core/ambidefs.h"
#include "core/bufferline.h"
#include "core/devformat.h"
#include "core/device.h"
#include "core/effectslot.h"
#include "core/mixer.h"
#include "core/mixer/defs.h"
#include "intrusive_ptr.h"
struct ContextBase;
namespace {
#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 */
struct CompressorState final : public EffectState {
/* Effect gains for each channel */
struct TargetGain {
uint mTarget{InvalidChannelIndex};
float mGain{1.0f};
};
std::array<TargetGain,MaxAmbiChannels> mChans;
/* Effect parameters */
bool mEnabled{true};
float mAttackMult{1.0f};
float mReleaseMult{1.0f};
float mEnvFollower{1.0f};
void deviceUpdate(const DeviceBase *device, const BufferStorage *buffer) override;
void update(const ContextBase *context, const EffectSlot *slot, const EffectProps *props,
const EffectTarget target) override;
void process(const size_t samplesToDo, const al::span<const FloatBufferLine> samplesIn,
const al::span<FloatBufferLine> samplesOut) override;
};
void CompressorState::deviceUpdate(const DeviceBase *device, const BufferStorage*)
{
/* Number of samples to do a full attack and release (non-integer sample
* counts are okay).
*/
const float attackCount{static_cast<float>(device->Frequency) * ATTACK_TIME};
const float releaseCount{static_cast<float>(device->Frequency) * RELEASE_TIME};
/* Calculate per-sample multipliers to attack and release at the desired
* rates.
*/
mAttackMult = std::pow(AMP_ENVELOPE_MAX/AMP_ENVELOPE_MIN, 1.0f/attackCount);
mReleaseMult = std::pow(AMP_ENVELOPE_MIN/AMP_ENVELOPE_MAX, 1.0f/releaseCount);
}
void CompressorState::update(const ContextBase*, const EffectSlot *slot,
const EffectProps *props, const EffectTarget target)
{
mEnabled = std::get<CompressorProps>(*props).OnOff;
mOutTarget = target.Main->Buffer;
auto set_channel = [this](size_t idx, uint outchan, float outgain)
{
mChans[idx].mTarget = outchan;
mChans[idx].mGain = outgain;
};
target.Main->setAmbiMixParams(slot->Wet, slot->Gain, set_channel);
}
void CompressorState::process(const size_t samplesToDo,
const al::span<const FloatBufferLine> samplesIn, const al::span<FloatBufferLine> samplesOut)
{
for(size_t base{0u};base < samplesToDo;)
{
std::array<float,256> gains;
const size_t td{minz(gains.size(), samplesToDo-base)};
/* Generate the per-sample gains from the signal envelope. */
float env{mEnvFollower};
if(mEnabled)
{
for(size_t i{0u};i < td;++i)
{
/* Clamp the absolute amplitude to the defined envelope limits,
* then attack or release the envelope to reach it.
*/
const float amplitude{clampf(std::fabs(samplesIn[0][base+i]), AMP_ENVELOPE_MIN,
AMP_ENVELOPE_MAX)};
if(amplitude > env)
env = minf(env*mAttackMult, amplitude);
else if(amplitude < env)
env = maxf(env*mReleaseMult, 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(size_t i{0u};i < td;++i)
{
const float amplitude{1.0f};
if(amplitude > env)
env = minf(env*mAttackMult, amplitude);
else if(amplitude < env)
env = maxf(env*mReleaseMult, amplitude);
gains[i] = 1.0f / env;
}
}
mEnvFollower = env;
/* Now compress the signal amplitude to output. */
auto chan = std::cbegin(mChans);
for(const auto &input : samplesIn)
{
const size_t outidx{chan->mTarget};
if(outidx != InvalidChannelIndex)
{
const float *RESTRICT src{input.data() + base};
float *RESTRICT dst{samplesOut[outidx].data() + base};
const float gain{chan->mGain};
if(!(std::fabs(gain) > GainSilenceThreshold))
{
for(size_t i{0u};i < td;i++)
dst[i] += src[i] * gains[i] * gain;
}
}
++chan;
}
base += td;
}
}
struct CompressorStateFactory final : public EffectStateFactory {
al::intrusive_ptr<EffectState> create() override
{ return al::intrusive_ptr<EffectState>{new CompressorState{}}; }
};
} // namespace
EffectStateFactory *CompressorStateFactory_getFactory()
{
static CompressorStateFactory CompressorFactory{};
return &CompressorFactory;
}
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