-/**

- * 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 "alcmain.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(const ALsizei samplesToDo, const FloatBufferLine *RESTRICT samplesIn, const ALsizei numInput, const al::span<FloatBufferLine> samplesOut) override;

-

- DEF_NEWDEL(ALautowahState)

-};

-

-ALboolean ALautowahState::deviceUpdate(const ALCdevice*)

-{

- /* (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;

-

- mOutTarget = target.Main->Buffer;

- for(size_t i{0u};i < slot->Wet.Buffer.size();++i)

- {

- auto coeffs = GetAmbiIdentityRow(i);

- ComputePanGains(target.Main, coeffs.data(), slot->Params.Gain, mChans[i].TargetGains);

- }

-}

-

-void ALautowahState::process(const ALsizei samplesToDo, const FloatBufferLine *RESTRICT samplesIn, const ALsizei numInput, const al::span<FloatBufferLine> samplesOut)

-{

- 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{mEnvDelay};

- for(ALsizei 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(ALsizei 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(ALsizei 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, 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;

-}