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/**
* OpenAL cross platform audio library
* Copyright (C) 2009 by Chris Robinson.
* 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 <algorithm>
#include <array>
#include <cstdlib>
#include <iterator>
#include "alc/effects/base.h"
#include "almalloc.h"
#include "alnumbers.h"
#include "alnumeric.h"
#include "alspan.h"
#include "core/ambidefs.h"
#include "core/bufferline.h"
#include "core/context.h"
#include "core/devformat.h"
#include "core/device.h"
#include "core/effectslot.h"
#include "core/filters/biquad.h"
#include "core/mixer.h"
#include "intrusive_ptr.h"
namespace {
using uint = unsigned int;
inline float Sin(uint index, float scale)
{ return std::sin(static_cast<float>(index) * scale); }
inline float Saw(uint index, float scale)
{ return static_cast<float>(index)*scale - 1.0f; }
inline float Square(uint index, float scale)
{ return (static_cast<float>(index)*scale < 0.5f)*2.0f - 1.0f; }
inline float One(uint, float)
{ return 1.0f; }
struct ModulatorState final : public EffectState {
template<float (&func)(uint,float)>
void Modulate(size_t todo)
{
const uint range{mRange};
const float scale{mIndexScale};
uint index{mIndex};
ASSUME(range > 1);
ASSUME(todo > 0);
for(size_t i{0};i < todo;)
{
size_t rem{minz(todo-i, range-index)};
do {
mModSamples[i++] = func(index++, scale);
} while(--rem);
if(index == range)
index = 0;
}
mIndex = index;
}
void (ModulatorState::*mGenModSamples)(size_t){};
uint mIndex{0};
uint mRange{1};
float mIndexScale{0.0f};
alignas(16) FloatBufferLine mModSamples{};
alignas(16) FloatBufferLine mBuffer{};
struct {
uint mTargetChannel{InvalidChannelIndex};
BiquadFilter mFilter;
float mCurrentGain{};
float mTargetGain{};
} mChans[MaxAmbiChannels];
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;
DEF_NEWDEL(ModulatorState)
};
template<>
void ModulatorState::Modulate<One>(size_t todo)
{
std::fill_n(mModSamples.begin(), todo, 1.0f);
mIndex = 0;
}
void ModulatorState::deviceUpdate(const DeviceBase*, const BufferStorage*)
{
for(auto &e : mChans)
{
e.mTargetChannel = InvalidChannelIndex;
e.mFilter.clear();
e.mCurrentGain = 0.0f;
}
}
void ModulatorState::update(const ContextBase *context, const EffectSlot *slot,
const EffectProps *props, const EffectTarget target)
{
const DeviceBase *device{context->mDevice};
/* The effective frequency will be adjusted to have a whole number of
* samples per cycle (at 48khz, that allows 8000, 6857.14, 6000, 5333.33,
* 4800, etc). We could do better by using fixed-point stepping over a sin
* function, with additive synthesis for the square and sawtooth waveforms,
* but that may need a more efficient sin function since it needs to do
* many iterations per sample.
*/
const float samplesPerCycle{props->Modulator.Frequency > 0.0f
? static_cast<float>(device->Frequency)/props->Modulator.Frequency + 0.5f
: 1.0f};
const uint range{static_cast<uint>(clampf(samplesPerCycle, 1.0f,
static_cast<float>(device->Frequency)))};
mIndex = static_cast<uint>(uint64_t{mIndex} * range / mRange);
mRange = range;
if(mRange == 1)
{
mIndexScale = 0.0f;
mGenModSamples = &ModulatorState::Modulate<One>;
}
else if(props->Modulator.Waveform == ModulatorWaveform::Sinusoid)
{
mIndexScale = al::numbers::pi_v<float>*2.0f / static_cast<float>(mRange);
mGenModSamples = &ModulatorState::Modulate<Sin>;
}
else if(props->Modulator.Waveform == ModulatorWaveform::Sawtooth)
{
mIndexScale = 2.0f / static_cast<float>(mRange-1);
mGenModSamples = &ModulatorState::Modulate<Saw>;
}
else /*if(props->Modulator.Waveform == ModulatorWaveform::Square)*/
{
/* For square wave, the range should be even (there should be an equal
* number of high and low samples). An odd number of samples per cycle
* would need a more complex value generator.
*/
mRange = (mRange+1) & ~1u;
mIndexScale = 1.0f / static_cast<float>(mRange-1);
mGenModSamples = &ModulatorState::Modulate<Square>;
}
float f0norm{props->Modulator.HighPassCutoff / static_cast<float>(device->Frequency)};
f0norm = clampf(f0norm, 1.0f/512.0f, 0.49f);
/* Bandwidth value is constant in octaves. */
mChans[0].mFilter.setParamsFromBandwidth(BiquadType::HighPass, f0norm, 1.0f, 0.75f);
for(size_t i{1u};i < slot->Wet.Buffer.size();++i)
mChans[i].mFilter.copyParamsFrom(mChans[0].mFilter);
mOutTarget = target.Main->Buffer;
auto set_channel = [this](size_t idx, uint outchan, float outgain)
{
mChans[idx].mTargetChannel = outchan;
mChans[idx].mTargetGain = outgain;
};
target.Main->setAmbiMixParams(slot->Wet, slot->Gain, set_channel);
}
void ModulatorState::process(const size_t samplesToDo, const al::span<const FloatBufferLine> samplesIn, const al::span<FloatBufferLine> samplesOut)
{
(this->*mGenModSamples)(samplesToDo);
auto chandata = std::begin(mChans);
for(const auto &input : samplesIn)
{
const size_t outidx{chandata->mTargetChannel};
if(outidx != InvalidChannelIndex)
{
chandata->mFilter.process({input.data(), samplesToDo}, mBuffer.data());
for(size_t i{0u};i < samplesToDo;++i)
mBuffer[i] *= mModSamples[i];
MixSamples({mBuffer.data(), samplesToDo}, samplesOut[outidx].data(),
chandata->mCurrentGain, chandata->mTargetGain, minz(samplesToDo, 64));
}
++chandata;
}
}
struct ModulatorStateFactory final : public EffectStateFactory {
al::intrusive_ptr<EffectState> create() override
{ return al::intrusive_ptr<EffectState>{new ModulatorState{}}; }
};
} // namespace
EffectStateFactory *ModulatorStateFactory_getFactory()
{
static ModulatorStateFactory ModulatorFactory{};
return &ModulatorFactory;
}
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