filter_config.h

/*
 * Copyright © 2015-2023 Synthstrom Audible Limited
 *
 * 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 "definitions_cxx.hpp"
#include "gui/l10n/strings.h"
#include "util/misc.h"
 
// non namespaced
enum class FilterMode {
    TRANSISTOR_12DB,
    TRANSISTOR_24DB,
    TRANSISTOR_24DB_DRIVE, // filter logic relies on ladders being first and contiguous
    SVF_BAND,              // first HPF mode
    SVF_NOTCH,             // last LPF mode
    HPLADDER,
    OFF, // Keep last as a sentinel. Signifies that the filter is not on, used for filter reset logic
};
constexpr int32_t kNumFilterModes = util::to_underlying(FilterMode::OFF);
constexpr FilterMode kLastLadder = FilterMode::TRANSISTOR_24DB_DRIVE;
// Off is not an LPF mode but is used to reset filters
constexpr int32_t kNumLPFModes = util::to_underlying(FilterMode::SVF_NOTCH) + 1;
constexpr FilterMode lastLpfMode = FilterMode::SVF_NOTCH;
constexpr FilterMode firstHPFMode = FilterMode::SVF_BAND;
constexpr int32_t kFirstHPFMode = util::to_underlying(FilterMode::SVF_BAND);
constexpr int32_t kNumHPFModes = util::to_underlying(FilterMode::OFF) - kFirstHPFMode;
enum class FilterRoute {
    HIGH_TO_LOW,
    LOW_TO_HIGH,
    PARALLEL,
};
 
constexpr int32_t kNumFilterRoutes = util::to_underlying(FilterRoute::PARALLEL) + 1;
 
FilterRoute stringToFilterRoute(char const* string);
char const* filterRouteToString(FilterRoute route);
 
char const* lpfTypeToString(FilterMode lpfType);
FilterMode stringToLPFType(char const* string);
 
namespace deluge::dsp::filter {
 
enum class FilterFamily { LP_LADDER, SVF, HP_LADDER, NONE };
constexpr uint8_t kNumFamilies = 3;
enum LpLadderType { LP12, LP24, DRIVE };
constexpr uint8_t kNumLadders = 3;
enum SVFType { BAND, NOTCH };
constexpr uint8_t kNumSVF = 2;
enum HPFType { HP12 };
constexpr uint8_t kNumHPLadders = 1;
 
using specificFilterType = uint8_t;
// must match order of filter family declaration for indexing to work
constexpr uint8_t numForVariant[kNumFamilies] = {kNumLadders, kNumSVF, kNumHPLadders};

class SpecificFilter {
public:
    SpecificFilter() = default;
    SpecificFilter(FilterMode mode) {
        switch (mode) {
        case FilterMode::OFF:
            family = FilterFamily::NONE;
            type = LpLadderType::LP12;
            break;
        case FilterMode::HPLADDER:
            family = FilterFamily::HP_LADDER;
            type = HPFType::HP12;
            break;
        case FilterMode::SVF_BAND:
            family = FilterFamily::SVF;
            type = SVFType::BAND;
            break;
        case FilterMode::SVF_NOTCH:
            family = FilterFamily::SVF;
            type = SVFType::NOTCH;
            break;
        case FilterMode::TRANSISTOR_12DB:
            family = FilterFamily::LP_LADDER;
            type = LpLadderType::LP12;
            break;
        case FilterMode::TRANSISTOR_24DB:
            family = FilterFamily::LP_LADDER;
            type = LpLadderType::LP24;
            break;
        case FilterMode::TRANSISTOR_24DB_DRIVE:
            family = FilterFamily::LP_LADDER;
            type = LpLadderType::DRIVE;
            break;
        }
    }
 
    FilterFamily getFamily() { return family; }
 
    specificFilterType getType() { return type; }
 
    [[nodiscard]] l10n::String getMorphName() const {
 
        switch (family) {
        case FilterFamily::LP_LADDER:
            return l10n::String::STRING_FOR_DRIVE;
        case FilterFamily::HP_LADDER:
            return l10n::String::STRING_FOR_FM;
        case FilterFamily::SVF:
            return l10n::String::STRING_FOR_MORPH;
        default:
            return l10n::String::STRING_FOR_NONE;
        };
    };
 
    SpecificFilter& incrementMode() {
        type = (type + 1) % numForVariant[util::to_underlying(family)];
        return *this;
    }
 
    FilterMode toMode() {
        int32_t baseNum = util::to_underlying(family);
        int32_t base = 0;
        for (int32_t i = 0; i < baseNum; i++) {
            int32_t famNum = numForVariant[i];
            base += famNum;
        }
        return static_cast<FilterMode>(base + type);
    }
 
private:
    FilterFamily family;
    specificFilterType type;
};
 
} // namespace deluge::dsp::filter