doux-copy/seq/docs/scripting.md

Scripting

Steps are programmed using Rhai, a simple scripting language.

Basic Syntax

Create sounds using sound() and chain parameters:

sound("kick").gain(0.8)

sound("hat").freq(8000).decay(0.1)

Context Variables

These are available in every step script:

• step: Current step index (0-based)
• beat: Current beat position
• bank: Current bank index
• pattern: Current pattern index
• tempo: Current BPM
• phase: Phase within the bar (0.0 to 1.0)
• slot: Slot number playing this pattern

Randomness

• rand(min, max): Random float in range
• rrand(min, max): Random integer in range (inclusive)
• seed(n): Set random seed for reproducibility

Variables

Store and retrieve values across steps:

• set("name", value): Store a value
• get("name"): Retrieve a value

Sound Parameters

Core

• sound(name): Create sound command
• freq(hz): Frequency
• note(midi): MIDI note number
• gain(amp): Volume (0.0-1.0)
• pan(pos): Stereo position (-1.0 to 1.0)
• dur(secs): Duration
• gate(secs): Gate time

Envelope

• attack(secs): Attack time
• decay(secs): Decay time
• sustain(level): Sustain level
• release(secs): Release time

Filter

• lpf(hz): Lowpass frequency
• lpq(q): Lowpass resonance
• hpf(hz): Highpass frequency
• bpf(hz): Bandpass frequency

Effects

• delay(mix): Delay amount
• delaytime(secs): Delay time
• delayfeedback(amt): Delay feedback
• verb(mix): Reverb amount
• verbdecay(secs): Reverb decay

Modulation

• vib(hz): Vibrato rate
• vibmod(amt): Vibrato depth
• fm(hz): FM modulator frequency
• fmh(ratio): FM harmonic ratio

Sample Playback

• speed(ratio): Playback speed
• begin(pos): Start position (0.0-1.0)
• end(pos): End position (0.0-1.0)

Examples

Conditional based on step:

if step % 4 == 0 {
    sound("kick").gain(1.0)
} else {
    sound("hat").gain(0.5)
}

Random variation:

sound("synth")
    .freq(rand(200.0, 800.0))
    .gain(rand(0.3, 0.7))

Using variables:

let n = get("counter");
set("counter", n + 1);
sound("beep").note(60 + (n % 12))