alc/effects/modulator.cpp

   1 /**
   2  * OpenAL cross platform audio library
   3  * Copyright (C) 2009 by Chris Robinson.
   4  * This library is free software; you can redistribute it and/or
   5  *  modify it under the terms of the GNU Library General Public
   6  *  License as published by the Free Software Foundation; either
   7  *  version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  *  Library General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Library General Public
  15  *  License along with this library; if not, write to the
  16  *  Free Software Foundation, Inc.,
  17  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  * Or go to http://www.gnu.org/copyleft/lgpl.html
  19  */
  20
  21 #include "config.h"
  22
  23 #include <algorithm>
  24 #include <array>
  25 #include <cstdlib>
  26 #include <iterator>
  27
  28 #include "alc/effects/base.h"
  29 #include "almalloc.h"
  30 #include "alnumbers.h"
  31 #include "alnumeric.h"
  32 #include "alspan.h"
  33 #include "core/ambidefs.h"
  34 #include "core/bufferline.h"
  35 #include "core/context.h"
  36 #include "core/devformat.h"
  37 #include "core/device.h"
  38 #include "core/effectslot.h"
  39 #include "core/filters/biquad.h"
  40 #include "core/mixer.h"
  41 #include "intrusive_ptr.h"
  42
  43
  44 namespace {
  45
  46 using uint = unsigned int;
  47
  48 #define MAX_UPDATE_SAMPLES 128
  49
  50 #define WAVEFORM_FRACBITS  24
  51 #define WAVEFORM_FRACONE   (1<<WAVEFORM_FRACBITS)
  52 #define WAVEFORM_FRACMASK  (WAVEFORM_FRACONE-1)
  53
  54 inline float Sin(uint index)
  55 {
  56     constexpr float scale{al::numbers::pi_v<float>*2.0f / WAVEFORM_FRACONE};
  57     return std::sin(static_cast<float>(index) * scale);
  58 }
  59
  60 inline float Saw(uint index)
  61 { return static_cast<float>(index)*(2.0f/WAVEFORM_FRACONE) - 1.0f; }
  62
  63 inline float Square(uint index)
  64 { return static_cast<float>(static_cast<int>((index>>(WAVEFORM_FRACBITS-2))&2) - 1); }
  65
  66 inline float One(uint) { return 1.0f; }
  67
  68 template<float (&func)(uint)>
  69 void Modulate(float *RESTRICT dst, uint index, const uint step, size_t todo)
  70 {
  71     for(size_t i{0u};i < todo;i++)
  72     {
  73         index += step;
  74         index &= WAVEFORM_FRACMASK;
  75         dst[i] = func(index);
  76     }
  77 }
  78
  79
  80 struct ModulatorState final : public EffectState {
  81     void (*mGetSamples)(float*RESTRICT, uint, const uint, size_t){};
  82
  83     uint mIndex{0};
  84     uint mStep{1};
  85
  86     struct {
  87         BiquadFilter Filter;
  88
  89         float CurrentGains[MAX_OUTPUT_CHANNELS]{};
  90         float TargetGains[MAX_OUTPUT_CHANNELS]{};
  91     } mChans[MaxAmbiChannels];
  92
  93
  94     void deviceUpdate(const DeviceBase *device, const Buffer &buffer) override;
  95     void update(const ContextBase *context, const EffectSlot *slot, const EffectProps *props,
  96         const EffectTarget target) override;
  97     void process(const size_t samplesToDo, const al::span<const FloatBufferLine> samplesIn,
  98         const al::span<FloatBufferLine> samplesOut) override;
  99
 100     DEF_NEWDEL(ModulatorState)
 101 };
 102
 103 void ModulatorState::deviceUpdate(const DeviceBase*, const Buffer&)
 104 {
 105     for(auto &e : mChans)
 106     {
 107         e.Filter.clear();
 108         std::fill(std::begin(e.CurrentGains), std::end(e.CurrentGains), 0.0f);
 109     }
 110 }
 111
 112 void ModulatorState::update(const ContextBase *context, const EffectSlot *slot,
 113     const EffectProps *props, const EffectTarget target)
 114 {
 115     const DeviceBase *device{context->mDevice};
 116
 117     const float step{props->Modulator.Frequency / static_cast<float>(device->Frequency)};
 118     mStep = fastf2u(clampf(step*WAVEFORM_FRACONE, 0.0f, float{WAVEFORM_FRACONE-1}));
 119
 120     if(mStep == 0)
 121         mGetSamples = Modulate<One>;
 122     else if(props->Modulator.Waveform == ModulatorWaveform::Sinusoid)
 123         mGetSamples = Modulate<Sin>;
 124     else if(props->Modulator.Waveform == ModulatorWaveform::Sawtooth)
 125         mGetSamples = Modulate<Saw>;
 126     else /*if(props->Modulator.Waveform == ModulatorWaveform::Square)*/
 127         mGetSamples = Modulate<Square>;
 128
 129     float f0norm{props->Modulator.HighPassCutoff / static_cast<float>(device->Frequency)};
 130     f0norm = clampf(f0norm, 1.0f/512.0f, 0.49f);
 131     /* Bandwidth value is constant in octaves. */
 132     mChans[0].Filter.setParamsFromBandwidth(BiquadType::HighPass, f0norm, 1.0f, 0.75f);
 133     for(size_t i{1u};i < slot->Wet.Buffer.size();++i)
 134         mChans[i].Filter.copyParamsFrom(mChans[0].Filter);
 135
 136     mOutTarget = target.Main->Buffer;
 137     auto set_gains = [slot,target](auto &chan, al::span<const float,MaxAmbiChannels> coeffs)
 138     { ComputePanGains(target.Main, coeffs.data(), slot->Gain, chan.TargetGains); };
 139     SetAmbiPanIdentity(std::begin(mChans), slot->Wet.Buffer.size(), set_gains);
 140 }
 141
 142 void ModulatorState::process(const size_t samplesToDo, const al::span<const FloatBufferLine> samplesIn, const al::span<FloatBufferLine> samplesOut)
 143 {
 144     for(size_t base{0u};base < samplesToDo;)
 145     {
 146         alignas(16) float modsamples[MAX_UPDATE_SAMPLES];
 147         const size_t td{minz(MAX_UPDATE_SAMPLES, samplesToDo-base)};
 148
 149         mGetSamples(modsamples, mIndex, mStep, td);
 150         mIndex += static_cast<uint>(mStep * td);
 151         mIndex &= WAVEFORM_FRACMASK;
 152
 153         auto chandata = std::begin(mChans);
 154         for(const auto &input : samplesIn)
 155         {
 156             alignas(16) float temps[MAX_UPDATE_SAMPLES];
 157
 158             chandata->Filter.process({&input[base], td}, temps);
 159             for(size_t i{0u};i < td;i++)
 160                 temps[i] *= modsamples[i];
 161
 162             MixSamples({temps, td}, samplesOut, chandata->CurrentGains, chandata->TargetGains,
 163                 samplesToDo-base, base);
 164             ++chandata;
 165         }
 166
 167         base += td;
 168     }
 169 }
 170
 171
 172 struct ModulatorStateFactory final : public EffectStateFactory {
 173     al::intrusive_ptr<EffectState> create() override
 174     { return al::intrusive_ptr<EffectState>{new ModulatorState{}}; }
 175 };
 176
 177 } // namespace
 178
 179 EffectStateFactory *ModulatorStateFactory_getFactory()
 180 {
 181     static ModulatorStateFactory ModulatorFactory{};
 182     return &ModulatorFactory;
 183 }