341 lines
14 KiB
C++
341 lines
14 KiB
C++
/**
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* OpenAL cross platform audio library
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* Copyright (C) 2013 by Mike Gorchak
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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 <cmath>
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#include <cstdlib>
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#include <algorithm>
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#include <functional>
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#include "al/auxeffectslot.h"
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#include "alcmain.h"
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#include "alcontext.h"
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#include "alu.h"
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#include "filters/biquad.h"
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#include "vecmat.h"
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namespace {
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/* The document "Effects Extension Guide.pdf" says that low and high *
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* frequencies are cutoff frequencies. This is not fully correct, they *
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* are corner frequencies for low and high shelf filters. If they were *
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* just cutoff frequencies, there would be no need in cutoff frequency *
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* gains, which are present. Documentation for "Creative Proteus X2" *
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* software describes 4-band equalizer functionality in a much better *
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* way. This equalizer seems to be a predecessor of OpenAL 4-band *
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* equalizer. With low and high shelf filters we are able to cutoff *
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* frequencies below and/or above corner frequencies using attenuation *
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* gains (below 1.0) and amplify all low and/or high frequencies using *
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* gains above 1.0. *
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* *
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* Low-shelf Low Mid Band High Mid Band High-shelf *
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* corner center center corner *
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* frequency frequency frequency frequency *
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* 50Hz..800Hz 200Hz..3000Hz 1000Hz..8000Hz 4000Hz..16000Hz *
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* *
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* | | | | *
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* | | | | *
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* B -----+ /--+--\ /--+--\ +----- *
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* O |\ | | | | | | /| *
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* O | \ - | - - | - / | *
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* S + | \ | | | | | | / | *
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* T | | | | | | | | | | *
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* ---------+---------------+------------------+---------------+-------- *
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* C | | | | | | | | | | *
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* U - | / | | | | | | \ | *
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* T | / - | - - | - \ | *
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* O |/ | | | | | | \| *
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* F -----+ \--+--/ \--+--/ +----- *
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* F | | | | *
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* | | | | *
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* *
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* Gains vary from 0.126 up to 7.943, which means from -18dB attenuation *
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* up to +18dB amplification. Band width varies from 0.01 up to 1.0 in *
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* octaves for two mid bands. *
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* *
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* Implementation is based on the "Cookbook formulae for audio EQ biquad *
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* filter coefficients" by Robert Bristow-Johnson *
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* http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt */
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struct EqualizerState final : public EffectState {
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struct {
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/* Effect parameters */
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BiquadFilter filter[4];
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/* Effect gains for each channel */
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float CurrentGains[MAX_OUTPUT_CHANNELS]{};
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float TargetGains[MAX_OUTPUT_CHANNELS]{};
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} mChans[MAX_AMBI_CHANNELS];
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FloatBufferLine mSampleBuffer{};
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void 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(const size_t samplesToDo, const al::span<const FloatBufferLine> samplesIn, const al::span<FloatBufferLine> samplesOut) override;
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DEF_NEWDEL(EqualizerState)
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};
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void EqualizerState::deviceUpdate(const ALCdevice*)
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{
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for(auto &e : mChans)
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{
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std::for_each(std::begin(e.filter), std::end(e.filter), std::mem_fn(&BiquadFilter::clear));
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std::fill(std::begin(e.CurrentGains), std::end(e.CurrentGains), 0.0f);
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}
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}
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void EqualizerState::update(const ALCcontext *context, const ALeffectslot *slot, const EffectProps *props, const EffectTarget target)
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{
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const ALCdevice *device{context->mDevice.get()};
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auto frequency = static_cast<float>(device->Frequency);
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float gain, f0norm;
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/* Calculate coefficients for the each type of filter. Note that the shelf
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* and peaking filters' gain is for the centerpoint of the transition band,
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* while the effect property gains are for the shelf/peak itself. So the
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* property gains need their dB halved (sqrt of linear gain) for the
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* shelf/peak to reach the provided gain.
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*/
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gain = std::sqrt(props->Equalizer.LowGain);
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f0norm = props->Equalizer.LowCutoff / frequency;
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mChans[0].filter[0].setParamsFromSlope(BiquadType::LowShelf, f0norm, gain, 0.75f);
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gain = std::sqrt(props->Equalizer.Mid1Gain);
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f0norm = props->Equalizer.Mid1Center / frequency;
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mChans[0].filter[1].setParamsFromBandwidth(BiquadType::Peaking, f0norm, gain,
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props->Equalizer.Mid1Width);
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gain = std::sqrt(props->Equalizer.Mid2Gain);
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f0norm = props->Equalizer.Mid2Center / frequency;
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mChans[0].filter[2].setParamsFromBandwidth(BiquadType::Peaking, f0norm, gain,
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props->Equalizer.Mid2Width);
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gain = std::sqrt(props->Equalizer.HighGain);
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f0norm = props->Equalizer.HighCutoff / frequency;
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mChans[0].filter[3].setParamsFromSlope(BiquadType::HighShelf, f0norm, gain, 0.75f);
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/* Copy the filter coefficients for the other input channels. */
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for(size_t i{1u};i < slot->Wet.Buffer.size();++i)
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{
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mChans[i].filter[0].copyParamsFrom(mChans[0].filter[0]);
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mChans[i].filter[1].copyParamsFrom(mChans[0].filter[1]);
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mChans[i].filter[2].copyParamsFrom(mChans[0].filter[2]);
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mChans[i].filter[3].copyParamsFrom(mChans[0].filter[3]);
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}
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mOutTarget = target.Main->Buffer;
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auto set_gains = [slot,target](auto &chan, al::span<const float,MAX_AMBI_CHANNELS> coeffs)
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{ ComputePanGains(target.Main, coeffs.data(), slot->Params.Gain, chan.TargetGains); };
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SetAmbiPanIdentity(std::begin(mChans), slot->Wet.Buffer.size(), set_gains);
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}
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void EqualizerState::process(const size_t samplesToDo, const al::span<const FloatBufferLine> samplesIn, const al::span<FloatBufferLine> samplesOut)
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{
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const al::span<float> buffer{mSampleBuffer.data(), samplesToDo};
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auto chandata = std::addressof(mChans[0]);
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for(const auto &input : samplesIn)
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{
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chandata->filter[0].process({input.data(), samplesToDo}, buffer.begin());
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chandata->filter[1].process(buffer, buffer.begin());
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chandata->filter[2].process(buffer, buffer.begin());
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chandata->filter[3].process(buffer, buffer.begin());
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MixSamples(buffer, samplesOut, chandata->CurrentGains, chandata->TargetGains, samplesToDo,
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0u);
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++chandata;
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}
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}
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void Equalizer_setParami(EffectProps*, ALenum param, int)
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{ throw effect_exception{AL_INVALID_ENUM, "Invalid equalizer integer property 0x%04x", param}; }
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void Equalizer_setParamiv(EffectProps*, ALenum param, const int*)
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{
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throw effect_exception{AL_INVALID_ENUM, "Invalid equalizer integer-vector property 0x%04x",
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param};
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}
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void Equalizer_setParamf(EffectProps *props, ALenum param, float val)
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{
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switch(param)
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{
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case AL_EQUALIZER_LOW_GAIN:
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if(!(val >= AL_EQUALIZER_MIN_LOW_GAIN && val <= AL_EQUALIZER_MAX_LOW_GAIN))
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throw effect_exception{AL_INVALID_VALUE, "Equalizer low-band gain out of range"};
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props->Equalizer.LowGain = val;
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break;
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case AL_EQUALIZER_LOW_CUTOFF:
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if(!(val >= AL_EQUALIZER_MIN_LOW_CUTOFF && val <= AL_EQUALIZER_MAX_LOW_CUTOFF))
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throw effect_exception{AL_INVALID_VALUE, "Equalizer low-band cutoff out of range"};
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props->Equalizer.LowCutoff = val;
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break;
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case AL_EQUALIZER_MID1_GAIN:
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if(!(val >= AL_EQUALIZER_MIN_MID1_GAIN && val <= AL_EQUALIZER_MAX_MID1_GAIN))
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throw effect_exception{AL_INVALID_VALUE, "Equalizer mid1-band gain out of range"};
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props->Equalizer.Mid1Gain = val;
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break;
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case AL_EQUALIZER_MID1_CENTER:
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if(!(val >= AL_EQUALIZER_MIN_MID1_CENTER && val <= AL_EQUALIZER_MAX_MID1_CENTER))
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throw effect_exception{AL_INVALID_VALUE, "Equalizer mid1-band center out of range"};
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props->Equalizer.Mid1Center = val;
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break;
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case AL_EQUALIZER_MID1_WIDTH:
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if(!(val >= AL_EQUALIZER_MIN_MID1_WIDTH && val <= AL_EQUALIZER_MAX_MID1_WIDTH))
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throw effect_exception{AL_INVALID_VALUE, "Equalizer mid1-band width out of range"};
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props->Equalizer.Mid1Width = val;
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break;
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case AL_EQUALIZER_MID2_GAIN:
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if(!(val >= AL_EQUALIZER_MIN_MID2_GAIN && val <= AL_EQUALIZER_MAX_MID2_GAIN))
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throw effect_exception{AL_INVALID_VALUE, "Equalizer mid2-band gain out of range"};
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props->Equalizer.Mid2Gain = val;
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break;
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case AL_EQUALIZER_MID2_CENTER:
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if(!(val >= AL_EQUALIZER_MIN_MID2_CENTER && val <= AL_EQUALIZER_MAX_MID2_CENTER))
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throw effect_exception{AL_INVALID_VALUE, "Equalizer mid2-band center out of range"};
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props->Equalizer.Mid2Center = val;
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break;
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case AL_EQUALIZER_MID2_WIDTH:
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if(!(val >= AL_EQUALIZER_MIN_MID2_WIDTH && val <= AL_EQUALIZER_MAX_MID2_WIDTH))
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throw effect_exception{AL_INVALID_VALUE, "Equalizer mid2-band width out of range"};
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props->Equalizer.Mid2Width = val;
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break;
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case AL_EQUALIZER_HIGH_GAIN:
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if(!(val >= AL_EQUALIZER_MIN_HIGH_GAIN && val <= AL_EQUALIZER_MAX_HIGH_GAIN))
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throw effect_exception{AL_INVALID_VALUE, "Equalizer high-band gain out of range"};
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props->Equalizer.HighGain = val;
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break;
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case AL_EQUALIZER_HIGH_CUTOFF:
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if(!(val >= AL_EQUALIZER_MIN_HIGH_CUTOFF && val <= AL_EQUALIZER_MAX_HIGH_CUTOFF))
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throw effect_exception{AL_INVALID_VALUE, "Equalizer high-band cutoff out of range"};
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props->Equalizer.HighCutoff = val;
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break;
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default:
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throw effect_exception{AL_INVALID_ENUM, "Invalid equalizer float property 0x%04x", param};
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}
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}
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void Equalizer_setParamfv(EffectProps *props, ALenum param, const float *vals)
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{ Equalizer_setParamf(props, param, vals[0]); }
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void Equalizer_getParami(const EffectProps*, ALenum param, int*)
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{ throw effect_exception{AL_INVALID_ENUM, "Invalid equalizer integer property 0x%04x", param}; }
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void Equalizer_getParamiv(const EffectProps*, ALenum param, int*)
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{
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throw effect_exception{AL_INVALID_ENUM, "Invalid equalizer integer-vector property 0x%04x",
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param};
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}
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void Equalizer_getParamf(const EffectProps *props, ALenum param, float *val)
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{
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switch(param)
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{
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case AL_EQUALIZER_LOW_GAIN:
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*val = props->Equalizer.LowGain;
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break;
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case AL_EQUALIZER_LOW_CUTOFF:
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*val = props->Equalizer.LowCutoff;
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break;
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case AL_EQUALIZER_MID1_GAIN:
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*val = props->Equalizer.Mid1Gain;
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break;
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case AL_EQUALIZER_MID1_CENTER:
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*val = props->Equalizer.Mid1Center;
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break;
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case AL_EQUALIZER_MID1_WIDTH:
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*val = props->Equalizer.Mid1Width;
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break;
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case AL_EQUALIZER_MID2_GAIN:
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*val = props->Equalizer.Mid2Gain;
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break;
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case AL_EQUALIZER_MID2_CENTER:
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*val = props->Equalizer.Mid2Center;
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break;
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case AL_EQUALIZER_MID2_WIDTH:
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*val = props->Equalizer.Mid2Width;
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break;
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case AL_EQUALIZER_HIGH_GAIN:
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*val = props->Equalizer.HighGain;
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break;
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case AL_EQUALIZER_HIGH_CUTOFF:
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*val = props->Equalizer.HighCutoff;
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break;
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default:
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throw effect_exception{AL_INVALID_ENUM, "Invalid equalizer float property 0x%04x", param};
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}
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}
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void Equalizer_getParamfv(const EffectProps *props, ALenum param, float *vals)
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{ Equalizer_getParamf(props, param, vals); }
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DEFINE_ALEFFECT_VTABLE(Equalizer);
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struct EqualizerStateFactory final : public EffectStateFactory {
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EffectState *create() override { return new EqualizerState{}; }
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EffectProps getDefaultProps() const noexcept override;
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const EffectVtable *getEffectVtable() const noexcept override { return &Equalizer_vtable; }
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};
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EffectProps EqualizerStateFactory::getDefaultProps() const noexcept
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{
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EffectProps props{};
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props.Equalizer.LowCutoff = AL_EQUALIZER_DEFAULT_LOW_CUTOFF;
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props.Equalizer.LowGain = AL_EQUALIZER_DEFAULT_LOW_GAIN;
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props.Equalizer.Mid1Center = AL_EQUALIZER_DEFAULT_MID1_CENTER;
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props.Equalizer.Mid1Gain = AL_EQUALIZER_DEFAULT_MID1_GAIN;
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props.Equalizer.Mid1Width = AL_EQUALIZER_DEFAULT_MID1_WIDTH;
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props.Equalizer.Mid2Center = AL_EQUALIZER_DEFAULT_MID2_CENTER;
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props.Equalizer.Mid2Gain = AL_EQUALIZER_DEFAULT_MID2_GAIN;
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props.Equalizer.Mid2Width = AL_EQUALIZER_DEFAULT_MID2_WIDTH;
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props.Equalizer.HighCutoff = AL_EQUALIZER_DEFAULT_HIGH_CUTOFF;
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props.Equalizer.HighGain = AL_EQUALIZER_DEFAULT_HIGH_GAIN;
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return props;
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}
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} // namespace
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EffectStateFactory *EqualizerStateFactory_getFactory()
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{
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static EqualizerStateFactory EqualizerFactory{};
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return &EqualizerFactory;
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}
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