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/**
* OpenAL cross platform audio library
* Copyright (C) 2018 by Raul Herraiz.
* 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 "config.h"
#include <cmath>
#include <cstdlib>
#include <algorithm>
#include "alMain.h"
#include "alcontext.h"
#include "alAuxEffectSlot.h"
#include "alError.h"
#include "alu.h"
#include "filters/biquad.h"
#include "vecmat.h"
namespace {
#define MIN_FREQ 20.0f
#define MAX_FREQ 2500.0f
#define Q_FACTOR 5.0f
struct ALautowahState final : public EffectState {
/* Effect parameters */
ALfloat mAttackRate;
ALfloat mReleaseRate;
ALfloat mResonanceGain;
ALfloat mPeakGain;
ALfloat mFreqMinNorm;
ALfloat mBandwidthNorm;
ALfloat mEnvDelay;
/* Filter components derived from the envelope. */
struct {
ALfloat cos_w0;
ALfloat alpha;
} mEnv[BUFFERSIZE];
struct {
/* Effect filters' history. */
struct {
ALfloat z1, z2;
} Filter;
/* Effect gains for each output channel */
ALfloat CurrentGains[MAX_OUTPUT_CHANNELS];
ALfloat TargetGains[MAX_OUTPUT_CHANNELS];
} mChans[MAX_AMBI_CHANNELS];
/* Effects buffers */
alignas(16) ALfloat mBufferOut[BUFFERSIZE];
ALboolean deviceUpdate(const ALCdevice *device) override;
void update(const ALCcontext *context, const ALeffectslot *slot, const EffectProps *props, const EffectTarget target) override;
void process(ALsizei samplesToDo, const ALfloat (*RESTRICT samplesIn)[BUFFERSIZE], const ALsizei numInput, ALfloat (*RESTRICT samplesOut)[BUFFERSIZE], const ALsizei numOutput) override;
DEF_NEWDEL(ALautowahState)
};
ALboolean ALautowahState::deviceUpdate(const ALCdevice *UNUSED(device))
{
/* (Re-)initializing parameters and clear the buffers. */
mAttackRate = 1.0f;
mReleaseRate = 1.0f;
mResonanceGain = 10.0f;
mPeakGain = 4.5f;
mFreqMinNorm = 4.5e-4f;
mBandwidthNorm = 0.05f;
mEnvDelay = 0.0f;
for(auto &e : mEnv)
{
e.cos_w0 = 0.0f;
e.alpha = 0.0f;
}
for(auto &chan : mChans)
{
std::fill(std::begin(chan.CurrentGains), std::end(chan.CurrentGains), 0.0f);
chan.Filter.z1 = 0.0f;
chan.Filter.z2 = 0.0f;
}
return AL_TRUE;
}
void ALautowahState::update(const ALCcontext *context, const ALeffectslot *slot, const EffectProps *props, const EffectTarget target)
{
const ALCdevice *device{context->Device};
const ALfloat ReleaseTime{clampf(props->Autowah.ReleaseTime, 0.001f, 1.0f)};
mAttackRate = expf(-1.0f / (props->Autowah.AttackTime*device->Frequency));
mReleaseRate = expf(-1.0f / (ReleaseTime*device->Frequency));
/* 0-20dB Resonance Peak gain */
mResonanceGain = std::sqrt(std::log10(props->Autowah.Resonance)*10.0f / 3.0f);
mPeakGain = 1.0f - std::log10(props->Autowah.PeakGain/AL_AUTOWAH_MAX_PEAK_GAIN);
mFreqMinNorm = MIN_FREQ / device->Frequency;
mBandwidthNorm = (MAX_FREQ-MIN_FREQ) / device->Frequency;
mOutBuffer = target.Main->Buffer;
mOutChannels = target.Main->NumChannels;
for(ALsizei i{0};i < slot->Wet.NumChannels;++i)
{
auto coeffs = GetAmbiIdentityRow(i);
ComputePanGains(target.Main, coeffs.data(), slot->Params.Gain, mChans[i].TargetGains);
}
}
void ALautowahState::process(ALsizei samplesToDo, const ALfloat (*RESTRICT samplesIn)[BUFFERSIZE], const ALsizei numInput, ALfloat (*RESTRICT samplesOut)[BUFFERSIZE], const ALsizei numOutput)
{
const ALfloat attack_rate = mAttackRate;
const ALfloat release_rate = mReleaseRate;
const ALfloat res_gain = mResonanceGain;
const ALfloat peak_gain = mPeakGain;
const ALfloat freq_min = mFreqMinNorm;
const ALfloat bandwidth = mBandwidthNorm;
ALfloat env_delay;
ALsizei c, i;
env_delay = mEnvDelay;
for(i = 0;i < samplesToDo;i++)
{
ALfloat w0, sample, a;
/* Envelope follower described on the book: Audio Effects, Theory,
* Implementation and Application.
*/
sample = peak_gain * std::fabs(samplesIn[0][i]);
a = (sample > env_delay) ? attack_rate : release_rate;
env_delay = lerp(sample, env_delay, a);
/* Calculate the cos and alpha components for this sample's filter. */
w0 = minf((bandwidth*env_delay + freq_min), 0.46f) * al::MathDefs<float>::Tau();
mEnv[i].cos_w0 = cosf(w0);
mEnv[i].alpha = sinf(w0)/(2.0f * Q_FACTOR);
}
mEnvDelay = env_delay;
ASSUME(numInput > 0);
for(c = 0;c < numInput;++c)
{
/* This effectively inlines BiquadFilter_setParams for a peaking
* filter and BiquadFilter_processC. The alpha and cosine components
* for the filter coefficients were previously calculated with the
* envelope. Because the filter changes for each sample, the
* coefficients are transient and don't need to be held.
*/
ALfloat z1 = mChans[c].Filter.z1;
ALfloat z2 = mChans[c].Filter.z2;
for(i = 0;i < samplesToDo;i++)
{
const ALfloat alpha = mEnv[i].alpha;
const ALfloat cos_w0 = mEnv[i].cos_w0;
ALfloat input, output;
ALfloat a[3], b[3];
b[0] = 1.0f + alpha*res_gain;
b[1] = -2.0f * cos_w0;
b[2] = 1.0f - alpha*res_gain;
a[0] = 1.0f + alpha/res_gain;
a[1] = -2.0f * cos_w0;
a[2] = 1.0f - alpha/res_gain;
input = samplesIn[c][i];
output = input*(b[0]/a[0]) + z1;
z1 = input*(b[1]/a[0]) - output*(a[1]/a[0]) + z2;
z2 = input*(b[2]/a[0]) - output*(a[2]/a[0]);
mBufferOut[i] = output;
}
mChans[c].Filter.z1 = z1;
mChans[c].Filter.z2 = z2;
/* Now, mix the processed sound data to the output. */
MixSamples(mBufferOut, numOutput, samplesOut, mChans[c].CurrentGains,
mChans[c].TargetGains, samplesToDo, 0, samplesToDo);
}
}
void ALautowah_setParamf(EffectProps *props, ALCcontext *context, ALenum param, ALfloat val)
{
switch(param)
{
case AL_AUTOWAH_ATTACK_TIME:
if(!(val >= AL_AUTOWAH_MIN_ATTACK_TIME && val <= AL_AUTOWAH_MAX_ATTACK_TIME))
SETERR_RETURN(context, AL_INVALID_VALUE,,"Autowah attack time out of range");
props->Autowah.AttackTime = val;
break;
case AL_AUTOWAH_RELEASE_TIME:
if(!(val >= AL_AUTOWAH_MIN_RELEASE_TIME && val <= AL_AUTOWAH_MAX_RELEASE_TIME))
SETERR_RETURN(context, AL_INVALID_VALUE,,"Autowah release time out of range");
props->Autowah.ReleaseTime = val;
break;
case AL_AUTOWAH_RESONANCE:
if(!(val >= AL_AUTOWAH_MIN_RESONANCE && val <= AL_AUTOWAH_MAX_RESONANCE))
SETERR_RETURN(context, AL_INVALID_VALUE,,"Autowah resonance out of range");
props->Autowah.Resonance = val;
break;
case AL_AUTOWAH_PEAK_GAIN:
if(!(val >= AL_AUTOWAH_MIN_PEAK_GAIN && val <= AL_AUTOWAH_MAX_PEAK_GAIN))
SETERR_RETURN(context, AL_INVALID_VALUE,,"Autowah peak gain out of range");
props->Autowah.PeakGain = val;
break;
default:
alSetError(context, AL_INVALID_ENUM, "Invalid autowah float property 0x%04x", param);
}
}
void ALautowah_setParamfv(EffectProps *props, ALCcontext *context, ALenum param, const ALfloat *vals)
{ ALautowah_setParamf(props, context, param, vals[0]); }
void ALautowah_setParami(EffectProps*, ALCcontext *context, ALenum param, ALint)
{ alSetError(context, AL_INVALID_ENUM, "Invalid autowah integer property 0x%04x", param); }
void ALautowah_setParamiv(EffectProps*, ALCcontext *context, ALenum param, const ALint*)
{ alSetError(context, AL_INVALID_ENUM, "Invalid autowah integer vector property 0x%04x", param); }
void ALautowah_getParamf(const EffectProps *props, ALCcontext *context, ALenum param, ALfloat *val)
{
switch(param)
{
case AL_AUTOWAH_ATTACK_TIME:
*val = props->Autowah.AttackTime;
break;
case AL_AUTOWAH_RELEASE_TIME:
*val = props->Autowah.ReleaseTime;
break;
case AL_AUTOWAH_RESONANCE:
*val = props->Autowah.Resonance;
break;
case AL_AUTOWAH_PEAK_GAIN:
*val = props->Autowah.PeakGain;
break;
default:
alSetError(context, AL_INVALID_ENUM, "Invalid autowah float property 0x%04x", param);
}
}
void ALautowah_getParamfv(const EffectProps *props, ALCcontext *context, ALenum param, ALfloat *vals)
{ ALautowah_getParamf(props, context, param, vals); }
void ALautowah_getParami(const EffectProps*, ALCcontext *context, ALenum param, ALint*)
{ alSetError(context, AL_INVALID_ENUM, "Invalid autowah integer property 0x%04x", param); }
void ALautowah_getParamiv(const EffectProps*, ALCcontext *context, ALenum param, ALint*)
{ alSetError(context, AL_INVALID_ENUM, "Invalid autowah integer vector property 0x%04x", param); }
DEFINE_ALEFFECT_VTABLE(ALautowah);
struct AutowahStateFactory final : public EffectStateFactory {
EffectState *create() override { return new ALautowahState{}; }
EffectProps getDefaultProps() const noexcept override;
const EffectVtable *getEffectVtable() const noexcept override { return &ALautowah_vtable; }
};
EffectProps AutowahStateFactory::getDefaultProps() const noexcept
{
EffectProps props{};
props.Autowah.AttackTime = AL_AUTOWAH_DEFAULT_ATTACK_TIME;
props.Autowah.ReleaseTime = AL_AUTOWAH_DEFAULT_RELEASE_TIME;
props.Autowah.Resonance = AL_AUTOWAH_DEFAULT_RESONANCE;
props.Autowah.PeakGain = AL_AUTOWAH_DEFAULT_PEAK_GAIN;
return props;
}
} // namespace
EffectStateFactory *AutowahStateFactory_getFactory()
{
static AutowahStateFactory AutowahFactory{};
return &AutowahFactory;
}