/** Oscillator waveform available to a pitched synth voice. */
export type SynthWave = "sine" | "square" | "sawtooth" | "triangle";
/** Biquad filter shape a noise voice is coloured through. */
export type SynthFilter = "lowpass" | "highpass" | "bandpass";
/**
 * A pitched oscillator voice: a 12ms linear attack to `gain`, then an
 * exponential decay to silence across `duration`, with an optional
 * exponential pitch slide from `freq` to `slideTo`.
 */
export interface ToneVoice {
    kind: "tone";
    /** Start frequency in Hz. */
    freq: number;
    /** Total voice length in seconds (the decay spans this). */
    duration: number;
    /** Peak gain before patch/bus scaling. Default 1. */
    gain?: number;
    /** Oscillator waveform. Default "sine". */
    wave?: SynthWave;
    /** Start offset in seconds from the cue trigger. Default 0. */
    delay?: number;
    /** When set, pitch ramps exponentially from `freq` to this Hz across `duration`. */
    slideTo?: number;
    /** Attack ramp in seconds. Default 0.012. */
    attack?: number;
    /**
     * Seconds held at full gain after the attack, before the decay to silence at `duration`.
     * Default 0 — a plain percussive decay. Set it to `duration` for a flat, sustained bed:
     * a looped buffer only reads as continuous if its amplitude does not fall across the loop,
     * so ambient hums and wind beds need this or they pulse once per loop.
     */
    sustain?: number;
}
/**
 * A filtered white-noise burst — impacts, whooshes, breath, crackle. Realised
 * from a shared 1s noise buffer at a randomised playback rate and start offset,
 * decaying exponentially to silence at `duration * decay`.
 */
export interface NoiseVoice {
    kind: "noise";
    /** Total voice length in seconds. */
    duration: number;
    /** Biquad cutoff/centre in Hz. */
    filterFreq: number;
    /** Peak gain before patch/bus scaling. Default 1. */
    gain?: number;
    /** Filter shape. Default "lowpass". */
    filterType?: SynthFilter;
    /** Fraction of `duration` over which the burst decays to silence. Default 0.9. */
    decay?: number;
    /** Start offset in seconds from the cue trigger. Default 0. */
    delay?: number;
    /**
     * Seconds held at full gain before the decay begins. Default 0. Set it to `duration` for a
     * flat noise bed (wind, rain, machine roar) that loops without pulsing.
     */
    sustain?: number;
}
/** One layered voice of a synth cue. */
export type SynthVoice = ToneVoice | NoiseVoice;
/**
 * A procedural sound cue: a set of voices triggered together, each with its own
 * `delay`, summed into one one-shot. Pure serialisable data — the shell realises
 * it on Web Audio, so the same catalog runs headless in tests with no `AudioContext`.
 */
export interface SynthPatch {
    voices: readonly SynthVoice[];
    /** Overall cue gain multiplier applied to every voice. Default 1. */
    gain?: number;
}
/** Total wall-clock length of a patch in seconds — the latest voice end across all voices. */
export declare function patchDuration(patch: SynthPatch): number;