alc/effects/fshifter.cpp

   1 /**
   2  * OpenAL cross platform audio library
   3  * Copyright (C) 2018 by Raul Herraiz.
   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 <cmath>
  26 #include <complex>
  27 #include <cstdlib>
  28 #include <iterator>
  29
  30 #include "alc/effects/base.h"
  31 #include "alcomplex.h"
  32 #include "almalloc.h"
  33 #include "alnumbers.h"
  34 #include "alnumeric.h"
  35 #include "alspan.h"
  36 #include "core/bufferline.h"
  37 #include "core/context.h"
  38 #include "core/devformat.h"
  39 #include "core/device.h"
  40 #include "core/effectslot.h"
  41 #include "core/mixer.h"
  42 #include "core/mixer/defs.h"
  43 #include "intrusive_ptr.h"
  44
  45
  46 namespace {
  47
  48 using uint = unsigned int;
  49 using complex_d = std::complex<double>;
  50
  51 #define HIL_SIZE 1024
  52 #define OVERSAMP (1<<2)
  53
  54 #define HIL_STEP     (HIL_SIZE / OVERSAMP)
  55 #define FIFO_LATENCY (HIL_STEP * (OVERSAMP-1))
  56
  57 /* Define a Hann window, used to filter the HIL input and output. */
  58 std::array<double,HIL_SIZE> InitHannWindow()
  59 {
  60     std::array<double,HIL_SIZE> ret;
  61     /* Create lookup table of the Hann window for the desired size, i.e. HIL_SIZE */
  62     for(size_t i{0};i < HIL_SIZE>>1;i++)
  63     {
  64         constexpr double scale{al::numbers::pi / double{HIL_SIZE}};
  65         const double val{std::sin(static_cast<double>(i+1) * scale)};
  66         ret[i] = ret[HIL_SIZE-1-i] = val * val;
  67     }
  68     return ret;
  69 }
  70 alignas(16) const std::array<double,HIL_SIZE> HannWindow = InitHannWindow();
  71
  72
  73 struct FshifterState final : public EffectState {
  74     /* Effect parameters */
  75     size_t mCount{};
  76     size_t mPos{};
  77     uint mPhaseStep[2]{};
  78     uint mPhase[2]{};
  79     double mSign[2]{};
  80
  81     /* Effects buffers */
  82     double mInFIFO[HIL_SIZE]{};
  83     complex_d mOutFIFO[HIL_STEP]{};
  84     complex_d mOutputAccum[HIL_SIZE]{};
  85     complex_d mAnalytic[HIL_SIZE]{};
  86     complex_d mOutdata[BufferLineSize]{};
  87
  88     alignas(16) float mBufferOut[BufferLineSize]{};
  89
  90     /* Effect gains for each output channel */
  91     struct {
  92         float Current[MAX_OUTPUT_CHANNELS]{};
  93         float Target[MAX_OUTPUT_CHANNELS]{};
  94     } mGains[2];
  95
  96
  97     void deviceUpdate(const DeviceBase *device, const Buffer &buffer) override;
  98     void update(const ContextBase *context, const EffectSlot *slot, const EffectProps *props,
  99         const EffectTarget target) override;
 100     void process(const size_t samplesToDo, const al::span<const FloatBufferLine> samplesIn,
 101         const al::span<FloatBufferLine> samplesOut) override;
 102
 103     DEF_NEWDEL(FshifterState)
 104 };
 105
 106 void FshifterState::deviceUpdate(const DeviceBase*, const Buffer&)
 107 {
 108     /* (Re-)initializing parameters and clear the buffers. */
 109     mCount = 0;
 110     mPos = FIFO_LATENCY;
 111
 112     std::fill(std::begin(mPhaseStep),   std::end(mPhaseStep),   0u);
 113     std::fill(std::begin(mPhase),       std::end(mPhase),       0u);
 114     std::fill(std::begin(mSign),        std::end(mSign),        1.0);
 115     std::fill(std::begin(mInFIFO),      std::end(mInFIFO),      0.0);
 116     std::fill(std::begin(mOutFIFO),     std::end(mOutFIFO),     complex_d{});
 117     std::fill(std::begin(mOutputAccum), std::end(mOutputAccum), complex_d{});
 118     std::fill(std::begin(mAnalytic),    std::end(mAnalytic),    complex_d{});
 119
 120     for(auto &gain : mGains)
 121     {
 122         std::fill(std::begin(gain.Current), std::end(gain.Current), 0.0f);
 123         std::fill(std::begin(gain.Target), std::end(gain.Target), 0.0f);
 124     }
 125 }
 126
 127 void FshifterState::update(const ContextBase *context, const EffectSlot *slot,
 128     const EffectProps *props, const EffectTarget target)
 129 {
 130     const DeviceBase *device{context->mDevice};
 131
 132     const float step{props->Fshifter.Frequency / static_cast<float>(device->Frequency)};
 133     mPhaseStep[0] = mPhaseStep[1] = fastf2u(minf(step, 1.0f) * MixerFracOne);
 134
 135     switch(props->Fshifter.LeftDirection)
 136     {
 137     case FShifterDirection::Down:
 138         mSign[0] = -1.0;
 139         break;
 140     case FShifterDirection::Up:
 141         mSign[0] = 1.0;
 142         break;
 143     case FShifterDirection::Off:
 144         mPhase[0]     = 0;
 145         mPhaseStep[0] = 0;
 146         break;
 147     }
 148
 149     switch(props->Fshifter.RightDirection)
 150     {
 151     case FShifterDirection::Down:
 152         mSign[1] = -1.0;
 153         break;
 154     case FShifterDirection::Up:
 155         mSign[1] = 1.0;
 156         break;
 157     case FShifterDirection::Off:
 158         mPhase[1]     = 0;
 159         mPhaseStep[1] = 0;
 160         break;
 161     }
 162
 163     const auto lcoeffs = CalcDirectionCoeffs({-1.0f, 0.0f, 0.0f}, 0.0f);
 164     const auto rcoeffs = CalcDirectionCoeffs({ 1.0f, 0.0f, 0.0f}, 0.0f);
 165
 166     mOutTarget = target.Main->Buffer;
 167     ComputePanGains(target.Main, lcoeffs.data(), slot->Gain, mGains[0].Target);
 168     ComputePanGains(target.Main, rcoeffs.data(), slot->Gain, mGains[1].Target);
 169 }
 170
 171 void FshifterState::process(const size_t samplesToDo, const al::span<const FloatBufferLine> samplesIn, const al::span<FloatBufferLine> samplesOut)
 172 {
 173     for(size_t base{0u};base < samplesToDo;)
 174     {
 175         size_t todo{minz(HIL_STEP-mCount, samplesToDo-base)};
 176
 177         /* Fill FIFO buffer with samples data */
 178         const size_t pos{mPos};
 179         size_t count{mCount};
 180         do {
 181             mInFIFO[pos+count] = samplesIn[0][base];
 182             mOutdata[base] = mOutFIFO[count];
 183             ++base; ++count;
 184         } while(--todo);
 185         mCount = count;
 186
 187         /* Check whether FIFO buffer is filled */
 188         if(mCount < HIL_STEP) break;
 189         mCount = 0;
 190         mPos = (mPos+HIL_STEP) & (HIL_SIZE-1);
 191
 192         /* Real signal windowing and store in Analytic buffer */
 193         for(size_t src{mPos}, k{0u};src < HIL_SIZE;++src,++k)
 194             mAnalytic[k] = mInFIFO[src]*HannWindow[k];
 195         for(size_t src{0u}, k{HIL_SIZE-mPos};src < mPos;++src,++k)
 196             mAnalytic[k] = mInFIFO[src]*HannWindow[k];
 197
 198         /* Processing signal by Discrete Hilbert Transform (analytical signal). */
 199         complex_hilbert(mAnalytic);
 200
 201         /* Windowing and add to output accumulator */
 202         for(size_t dst{mPos}, k{0u};dst < HIL_SIZE;++dst,++k)
 203             mOutputAccum[dst] += 2.0/OVERSAMP*HannWindow[k]*mAnalytic[k];
 204         for(size_t dst{0u}, k{HIL_SIZE-mPos};dst < mPos;++dst,++k)
 205             mOutputAccum[dst] += 2.0/OVERSAMP*HannWindow[k]*mAnalytic[k];
 206
 207         /* Copy out the accumulated result, then clear for the next iteration. */
 208         std::copy_n(mOutputAccum + mPos, HIL_STEP, mOutFIFO);
 209         std::fill_n(mOutputAccum + mPos, HIL_STEP, complex_d{});
 210     }
 211
 212     /* Process frequency shifter using the analytic signal obtained. */
 213     float *RESTRICT BufferOut{mBufferOut};
 214     for(int c{0};c < 2;++c)
 215     {
 216         const uint phase_step{mPhaseStep[c]};
 217         uint phase_idx{mPhase[c]};
 218         for(size_t k{0};k < samplesToDo;++k)
 219         {
 220             const double phase{phase_idx * (al::numbers::pi*2.0 / MixerFracOne)};
 221             BufferOut[k] = static_cast<float>(mOutdata[k].real()*std::cos(phase) +
 222                 mOutdata[k].imag()*std::sin(phase)*mSign[c]);
 223
 224             phase_idx += phase_step;
 225             phase_idx &= MixerFracMask;
 226         }
 227         mPhase[c] = phase_idx;
 228
 229         /* Now, mix the processed sound data to the output. */
 230         MixSamples({BufferOut, samplesToDo}, samplesOut, mGains[c].Current, mGains[c].Target,
 231             maxz(samplesToDo, 512), 0);
 232     }
 233 }
 234
 235
 236 struct FshifterStateFactory final : public EffectStateFactory {
 237     al::intrusive_ptr<EffectState> create() override
 238     { return al::intrusive_ptr<EffectState>{new FshifterState{}}; }
 239 };
 240
 241 } // namespace
 242
 243 EffectStateFactory *FshifterStateFactory_getFactory()
 244 {
 245     static FshifterStateFactory FshifterFactory{};
 246     return &FshifterFactory;
 247 }