spessasynth_lib/soundfont/basic_soundfont/generator.js

/**
 * @enum {number}
 */
export const generatorTypes = {
    INVALID: -1,                        // invalid generator
    startAddrsOffset: 0,                // sample control - moves sample start point
    endAddrOffset: 1,                   // sample control - moves sample end point
    startloopAddrsOffset: 2,            // loop control - moves loop start point
    endloopAddrsOffset: 3,              // loop control - moves loop end point
    startAddrsCoarseOffset: 4,          // sample control - moves sample start point in 32,768 increments
    modLfoToPitch: 5,                   // pitch modulation - modulation lfo pitch modulation in cents
    vibLfoToPitch: 6,                   // pitch modulation - vibrato lfo pitch modulation in cents
    modEnvToPitch: 7,                   // pitch modulation - modulation envelope pitch modulation in cents
    initialFilterFc: 8,                 // filter - lowpass filter cutoff in cents
    initialFilterQ: 9,                  // filter - lowpass filter resonance
    modLfoToFilterFc: 10,               // filter modulation - modulation lfo lowpass filter cutoff in cents
    modEnvToFilterFc: 11,               // filter modulation - modulation envelope lowpass filter cutoff in cents
    endAddrsCoarseOffset: 12,           // ample control - move sample end point in 32,768 increments
    modLfoToVolume: 13,                 // modulation lfo - volume (tremolo), where 100 = 10dB
    unused1: 14,                        // unused
    chorusEffectsSend: 15,              // effect send - how much is sent to chorus 0 - 1000
    reverbEffectsSend: 16,              // effect send - how much is sent to reverb 0 - 1000
    pan: 17,                            // panning - where -500 = left, 0 = center, 500 = right
    unused2: 18,                        // unused
    unused3: 19,                        // unused
    unused4: 20,                        // unused
    delayModLFO: 21,                    // mod lfo - delay for mod lfo to start from zero
    freqModLFO: 22,                     // mod lfo - frequency of mod lfo, 0 = 8.176 Hz, units: f => 1200log2(f/8.176)
    delayVibLFO: 23,                    // vib lfo - delay for vibrato lfo to start from zero
    freqVibLFO: 24,                     // vib lfo - frequency of vibrato lfo, 0 = 8.176Hz, unit: f => 1200log2(f/8.176)
    delayModEnv: 25,                    // mod env - 0 = 1 s decay till mod env starts
    attackModEnv: 26,                   // mod env - attack of mod env
    holdModEnv: 27,                     // mod env - hold of mod env
    decayModEnv: 28,                    // mod env - decay of mod env
    sustainModEnv: 29,                  // mod env - sustain of mod env
    releaseModEnv: 30,                  // mod env - release of mod env
    keyNumToModEnvHold: 31,             // mod env - also modulating mod envelope hold with key number
    keyNumToModEnvDecay: 32,            // mod env - also modulating mod envelope decay with key number
    delayVolEnv: 33,                    // vol env - delay of envelope from zero (weird scale)
    attackVolEnv: 34,                   // vol env - attack of envelope
    holdVolEnv: 35,                     // vol env - hold of envelope
    decayVolEnv: 36,                    // vol env - decay of envelope
    sustainVolEnv: 37,                  // vol env - sustain of envelope
    releaseVolEnv: 38,                  // vol env - release of envelope
    keyNumToVolEnvHold: 39,             // vol env - key number to volume envelope hold
    keyNumToVolEnvDecay: 40,            // vol env - key number to volume envelope decay
    instrument: 41,                     // zone - instrument index to use for preset zone
    reserved1: 42,                      // reserved
    keyRange: 43,                       // zone - key range for which preset / instrument zone is active
    velRange: 44,                       // zone - velocity range for which preset / instrument zone is active
    startloopAddrsCoarseOffset: 45,     // sample control - moves sample loop start point in 32,768 increments
    keyNum: 46,                         // zone - instrument only: always use this midi number (ignore what's pressed)
    velocity: 47,                       // zone - instrument only: always use this velocity (ignore what's pressed)
    initialAttenuation: 48,             // zone - allows turning down the volume, 10 = -1dB
    reserved2: 49,                      // reserved
    endloopAddrsCoarseOffset: 50,       // sample control - moves sample loop end point in 32,768 increments
    coarseTune: 51,                     // tune - pitch offset in semitones
    fineTune: 52,                       // tune - pitch offset in cents
    sampleID: 53,                       // sample - instrument zone only: which sample to use
    sampleModes: 54,                    // sample - 0 = no loop, 1 = loop, 2 = reserved, 3 = loop and play till the end in release phase
    reserved3: 55,                      // reserved
    scaleTuning: 56,                    // sample - the degree to which MIDI key number influences pitch, 100 = default
    exclusiveClass: 57,                 // sample - = cut = choke group
    overridingRootKey: 58,              // sample - can override the sample's original pitch
    unused5: 59,                        // unused
    endOper: 60                         // end marker
};
/**
 * @type {{min: number, max: number, def: number}[]}
 */
export const generatorLimits = [];
// offsets
generatorLimits[generatorTypes.startAddrsOffset] = { min: 0, max: 32768, def: 0 };
generatorLimits[generatorTypes.endAddrOffset] = { min: -32768, max: 32768, def: 0 };
generatorLimits[generatorTypes.startloopAddrsOffset] = { min: -32768, max: 32768, def: 0 };
generatorLimits[generatorTypes.endloopAddrsOffset] = { min: -32768, max: 32768, def: 0 };
generatorLimits[generatorTypes.startAddrsCoarseOffset] = { min: 0, max: 32768, def: 0 };

// pitch influence
generatorLimits[generatorTypes.modLfoToPitch] = { min: -12000, max: 12000, def: 0 };
generatorLimits[generatorTypes.vibLfoToPitch] = { min: -12000, max: 12000, def: 0 };
generatorLimits[generatorTypes.modEnvToPitch] = { min: -12000, max: 12000, def: 0 };

// lowpass
generatorLimits[generatorTypes.initialFilterFc] = { min: 1500, max: 13500, def: 13500 };
generatorLimits[generatorTypes.initialFilterQ] = { min: 0, max: 960, def: 0 };
generatorLimits[generatorTypes.modLfoToFilterFc] = { min: -12000, max: 12000, def: 0 };
generatorLimits[generatorTypes.modEnvToFilterFc] = { min: -12000, max: 12000, def: 0 };

generatorLimits[generatorTypes.endAddrsCoarseOffset] = { min: -32768, max: 32768, def: 0 };

generatorLimits[generatorTypes.modLfoToVolume] = { min: -960, max: 960, def: 0 };

// effects, pan
generatorLimits[generatorTypes.chorusEffectsSend] = { min: 0, max: 1000, def: 0 };
generatorLimits[generatorTypes.reverbEffectsSend] = { min: 0, max: 1000, def: 0 };
generatorLimits[generatorTypes.pan] = { min: -500, max: 500, def: 0 };

// lfo
generatorLimits[generatorTypes.delayModLFO] = { min: -12000, max: 5000, def: -12000 };
generatorLimits[generatorTypes.freqModLFO] = { min: -16000, max: 4500, def: 0 };
generatorLimits[generatorTypes.delayVibLFO] = { min: -12000, max: 5000, def: -12000 };
generatorLimits[generatorTypes.freqVibLFO] = { min: -16000, max: 4500, def: 0 };

// mod env
generatorLimits[generatorTypes.delayModEnv] = { min: -32768, max: 5000, def: -32768 }; // -32,768 indicates instant phase,
// this is done to prevent click at the start of filter modenv
generatorLimits[generatorTypes.attackModEnv] = { min: -32768, max: 8000, def: -32768 };
generatorLimits[generatorTypes.holdModEnv] = { min: -12000, max: 5000, def: -12000 };
generatorLimits[generatorTypes.decayModEnv] = { min: -12000, max: 8000, def: -12000 };
generatorLimits[generatorTypes.sustainModEnv] = { min: 0, max: 1000, def: 0 };
generatorLimits[generatorTypes.releaseModEnv] = { min: -7200, max: 8000, def: -12000 }; // min is set to -7200 to prevent lowpass clicks
// key num to mod env
generatorLimits[generatorTypes.keyNumToModEnvHold] = { min: -1200, max: 1200, def: 0 };
generatorLimits[generatorTypes.keyNumToModEnvDecay] = { min: -1200, max: 1200, def: 0 };

// vol env
generatorLimits[generatorTypes.delayVolEnv] = { min: -12000, max: 5000, def: -12000 };
generatorLimits[generatorTypes.attackVolEnv] = { min: -12000, max: 8000, def: -12000 };
generatorLimits[generatorTypes.holdVolEnv] = { min: -12000, max: 5000, def: -12000 };
generatorLimits[generatorTypes.decayVolEnv] = { min: -12000, max: 8000, def: -12000 };
generatorLimits[generatorTypes.sustainVolEnv] = { min: 0, max: 1440, def: 0 };
generatorLimits[generatorTypes.releaseVolEnv] = { min: -7200, max: 8000, def: -12000 }; // min is set to -7200 prevent clicks
// key num to vol env
generatorLimits[generatorTypes.keyNumToVolEnvHold] = { min: -1200, max: 1200, def: 0 };
generatorLimits[generatorTypes.keyNumToVolEnvDecay] = { min: -1200, max: 1200, def: 0 };

generatorLimits[generatorTypes.startloopAddrsCoarseOffset] = { min: -32768, max: 32768, def: 0 };
generatorLimits[generatorTypes.keyNum] = { min: -1, max: 127, def: -1 };
generatorLimits[generatorTypes.velocity] = { min: -1, max: 127, def: -1 };

generatorLimits[generatorTypes.initialAttenuation] = { min: 0, max: 1440, def: 0 };

generatorLimits[generatorTypes.endloopAddrsCoarseOffset] = { min: -32768, max: 32768, def: 0 };

generatorLimits[generatorTypes.coarseTune] = { min: -120, max: 120, def: 0 };
generatorLimits[generatorTypes.fineTune] = { min: -12700, max: 12700, def: 0 }; // this generator is used as initial pitch, hence this range
generatorLimits[generatorTypes.scaleTuning] = { min: 0, max: 1200, def: 100 };
generatorLimits[generatorTypes.exclusiveClass] = { min: 0, max: 99999, def: 0 };
generatorLimits[generatorTypes.overridingRootKey] = { min: 0 - 1, max: 127, def: -1 };
generatorLimits[generatorTypes.sampleModes] = { min: 0, max: 3, def: 0 };

export class Generator
{
    /**
     * The generator's enum number
     * @type {generatorTypes|number}
     */
    generatorType = generatorTypes.INVALID;
    /**
     * The generator's 16-bit value
     * @type {number}
     */
    generatorValue = 0;
    
    /**
     * Constructs a new generator
     * @param type {generatorTypes|number}
     * @param value {number}
     * @param validate {boolean}
     */
    constructor(type = generatorTypes.INVALID, value = 0, validate = true)
    {
        this.generatorType = type;
        if (value === undefined)
        {
            throw new Error("No value provided.");
        }
        this.generatorValue = Math.round(value);
        if (validate)
        {
            const lim = generatorLimits[type];
            
            if (lim !== undefined)
            {
                this.generatorValue = Math.max(lim.min, Math.min(lim.max, this.generatorValue));
            }
        }
    }
}

/**
 * generator.js
 * purpose: contains enums for generators,
 * and their limis parses reads soundfont generators, sums them and applies limits
 */
/**
 * @param generatorType {number}
 * @param presetGens {Generator[]}
 * @param instrumentGens {Generator[]}
 */
export function addAndClampGenerator(generatorType, presetGens, instrumentGens)
{
    const limits = generatorLimits[generatorType] || { min: 0, max: 32768, def: 0 };
    let presetGen = presetGens.find(g => g.generatorType === generatorType);
    let presetValue = 0;
    if (presetGen)
    {
        presetValue = presetGen.generatorValue;
    }
    
    let instruGen = instrumentGens.find(g => g.generatorType === generatorType);
    let instruValue = limits.def;
    if (instruGen)
    {
        instruValue = instruGen.generatorValue;
    }
    
    let value = instruValue + presetValue;
    
    // Special case, initial attenuation.
    // Shall get clamped in the volume envelope,
    // so the modulators can be affected by negative generators (the "Brass" patch was problematic...)
    if (generatorType === generatorTypes.initialAttenuation)
    {
        return value;
    }
    
    return Math.max(limits.min, Math.min(limits.max, value));
}