GranularProcessor.h

/*
 * Copyright © 2024 Mark Adams and Alter-Alter
 *
 * This file is part of The Synthstrom Audible Deluge Firmware.
 *
 * The Synthstrom Audible Deluge Firmware is free software: you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free Software Foundation,
 * either version 3 of the License, or (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program.
 * If not, see <https://www.gnu.org/licenses/>.
 */
 
#pragma once
 
#include "GranularProcessor.h"
#include "OSLikeStuff/scheduler_api.h"
#include "definitions_cxx.hpp"
#include "dsp/filter/ladder_components.h"
#include "dsp/stereo_sample.h"
#include "memory/stealable.h"
#include "modulation/lfo.h"
#include <span>
 
class UnpatchedParamSet;
 
struct Grain {
    int32_t length = 0; // in samples 0=OFF
    int32_t startPoint; // starttimepos in samples
    int32_t counter;    // relative pos in samples
    uint16_t pitch;     // 1024=1.0
    int32_t volScale;
    int32_t volScaleMax;
    bool rev;        // 0=normal, 1 =reverse
    int32_t panVolL; // 0 - 1073741823
    int32_t panVolR; // 0 - 1073741823
};
class GrainBuffer;

class GranularProcessor {
public:
    GranularProcessor() { getBuffer(); }
    GranularProcessor(const GranularProcessor& other); // copy constructor
    ~GranularProcessor();
    [[nodiscard]] int32_t getSamplesToShutdown() const { return wrapsToShutdown * kModFXGrainBufferSize; }

    void startSkippingRendering();

    void processGrainFX(std::span<StereoSample> buffer, int32_t grainRate, int32_t grainMix, int32_t grainDensity,
                        int32_t pitchRandomness, int32_t* postFXVolume, bool anySoundComingIn, float tempoBPM,
                        q31_t reverbAmount);
 
    void clearGrainFXBuffer();
    void grainBufferStolen() { grainBuffer = nullptr; }
 
private:
    void setupGrainFX(int32_t grainRate, int32_t grainMix, int32_t grainDensity, int32_t pitchRandomness,
                      int32_t* postFXVolume, float timePerInternalTick);
    StereoSample processOneGrainSample(StereoSample currentSample);
    void getBuffer();
    void setWrapsToShutdown();
    void setupGrainsIfNeeded(int32_t writeIndex);
    // parameters
    uint32_t bufferWriteIndex = 0;
    int32_t _grainSize = 13230;                                 // 300ms
    int32_t _grainRate = 1260;                                  // 35hz
    int32_t _grainShift = 13230;                                // 300ms
    int32_t _grainFeedbackVol = 161061273;                      // Q30: 0.15
    int32_t _grainVol = 0;                                      // Q31: 0
    int32_t _grainDryVol = std::numeric_limits<int32_t>::max(); // Q31: 1
    int32_t _pitchRandomness = 0;
 
    bool grainLastTickCountIsZero = true;
    bool grainInitialized = false;
 
    std::array<Grain, 8> grains = {0};
 
    int32_t wrapsToShutdown = 0;
    GrainBuffer* grainBuffer = nullptr;
    int32_t _densityKnobPos = 0;
    int32_t _rateKnobPos = 0;
    int32_t _mixKnobPos = 0; // Q31
    deluge::dsp::filter::BasicFilterComponent lpf_l{};
    deluge::dsp::filter::BasicFilterComponent lpf_r{};
    bool tempoSync = true;
    bool bufferFull = false;
};
 
class GrainBuffer : public Stealable {
public:
    GrainBuffer() = delete;
    GrainBuffer(GrainBuffer& other) = delete;
    GrainBuffer(const GrainBuffer& other) = delete;
    explicit GrainBuffer(GranularProcessor* grainFX) : owner(grainFX) {}
    bool mayBeStolen(void* thingNotToStealFrom) override {
        if (thingNotToStealFrom != this) {
            return !inUse;
        }
        return false;
    };
    void steal(char const* errorCode) override { owner->grainBufferStolen(); };
 
    // gives it  a high priority - these are huge so reallocating them can be slow
    [[nodiscard]] StealableQueue getAppropriateQueue() const override {
        return StealableQueue::CURRENT_SONG_SAMPLE_DATA_REPITCHED_CACHE;
    };
    StereoSample& operator[](int32_t i) { return sampleBuffer[i]; }
    StereoSample operator[](int32_t i) const { return sampleBuffer[i]; }
    bool inUse = true;
 
private:
    GranularProcessor* owner;
    std::array<StereoSample, kModFXGrainBufferSize * sizeof(StereoSample)> sampleBuffer;
};