// inspired by https://www.youtube.com/watch?v=Aktb_dmY4vk
// essentially, pass a bandpassed saw wave with vibrato and a bit of noise into a short reverb
//
// It is possible to not do the reverb, as the diffusion it does that creates the sound
// is essentially a number of parallel delays. A chorus of saw waves with random phases
// gives the same effect.
// bit slower, original is 210
ditty.bpm = 140;
input.hit = 800; //min=100, max=1000, step=1
input.damp = 6;//min=1, max=20, step=0.1
input.tuning = 0.5; //min=0.125, max=2, step=0.125
// Delay line
// from srtuss
class Delayline {
constructor(n) {
this.n = ~~n;
this.p = 0;
this.lastOut = 0;
this.data = new Float32Array(n);
}
clock(input) {
this.lastOut = this.data[this.p];
this.data[this.p] = input;
if (++this.p >= this.n) this.p = 0;
}
tap(offset) {
let x = this.p - (offset|0) - 1;
x %= this.n;
if (x < 0) x += this.n;
return this.data[x];
}
}
// SVF filter
// https://cytomic.com/files/dsp/SvfLinearTrapOptimised2.pdf
class Simper {
constructor() {
this.ic1eq = 0;
this.ic2eq = 0;
}
tick(v0, freq, q) {
const g = Math.tan(Math.PI * freq);
const k = 1 / q;
const a1 = 1 / (1 + g * (g + k));
const a2 = g * a1;
const a3 = g * a2;
// tick
const v3 = v0 - this.ic2eq;
const v1 = a1 * this.ic1eq + a2 * v3;
const v2 = this.ic2eq + a2 * this.ic1eq + a3 * v3;
// update
this.ic1eq = 2 * v1 - this.ic1eq;
this.ic2eq = 2 * v2 - this.ic2eq;
// low, band output
return [v2, v1];
}
}
function softclip(x) {
return x < -1 ? -1 : x > 1 ? 1 : 1.5*(1-x*x/3)*x;
}
function varsaw(p, formant) {
let x = p-~~p;
return (x - 0.5) * softclip(formant*x*(1-x)) * 2;
}
const osc = synth.def(
class {
constructor(options) {
// frequencies
this.freq = midi_to_hz(options.note);
// phasor
this.time = 0;
// hit filter
this.hit = new Simper();
// delay line
this.string = new Delayline(ditty.sampleRate);
// damping filter
this.damp = new Simper();
// body resonance delays
this.b1 = new Delayline(ditty.sampleRate);
this.b2 = new Delayline(ditty.sampleRate);
this.b3 = new Delayline(ditty.sampleRate);
this.b4 = new Delayline(ditty.sampleRate);
}
process(note, env, tick, options) {
// phasor times
this.time += ditty.dt;
// karplus strong
const inp = this.hit.tick(this.time < 0.01 ? Math.random() * 2 - 1 : 0, ditty.dt * input.hit, 0.707)[0];
const tap = ditty.sampleRate / (this.freq * input.tuning);
const sam = this.string.tap(tap) * env.value;
this.string.clock(this.damp.tick(sam + inp, this.freq * input.damp * ditty.dt, 0.707)[0]);
// resonance
const b1 = this.b1.tap(0.002 * ditty.sampleRate);
const b2 = this.b2.tap(0.003 * ditty.sampleRate);
const b3 = this.b3.tap(0.004 * ditty.sampleRate);
const b4 = this.b4.tap(0.012 * ditty.sampleRate);
this.b1.clock(sam + b1 * 0.2);
this.b2.clock(sam + b2 * 0.7);
this.b3.clock(sam + b3 * 0.3);
this.b4.clock(sam + b4 * 0.5);
return sam + b1 + b2 + b3 + b4;
}
}, {
// attack parameters
levels: [0, 1, 1, 0.9],
times: [0.005, 4, 1],
env: segenv,
}
);
// === original ===
// Forked from "Wizards & Warriors (main menu)" by romaindurand
// https://dittytoy.net/ditty/3066954356
function melodyPattern(notes, baseNote) {
return () => {
for(i = 0; i < notes.length; i++) {
if (notes[i] > 0) osc.play(notes[i], { duration: 0.5, pan: 0.2 - Math.random() * 0.1 });
sleep(0.5);
if (notes[i] > 0) osc.play(baseNote, { duration: 0.5, pan: 0.2 - Math.random() * 0.1 });
sleep(0.5);
}
};
}
function simpleMelodyPattern(notes) {
// calculate length for it to sound nice
let lens = new Array(notes.length).fill(0.45);
let last = 0;
// every off note adds to the on length of the last on note
for (let i = 0; i < lens.length; i++) {
if (notes[i] === 0) lens[last] += 0.5;
else last = i;
}
return () => {
for(let i = 0; i < notes.length; i++) {
if (notes[i] > 0) osc.play(notes[i], { duration: lens[i], pan: -0.2 - Math.random() * 0.1 });
sleep(0.5);
}
};
}
const melodySeq0 = () => {
melodyPattern([d5, e5, f5, g5], a4)();
melodyPattern([bb4, d5, g5, f5], g4)();
melodyPattern([e5, f5], c5)();
melodyPattern([g5, c5], g4)();
melodyPattern([bb4, a4, f5, e5], f4)();
const notes0 = [d5, e5, f5, d5];
melodyPattern(notes0, bb4)();
//same as previous pattern with another base note
melodyPattern(notes0, g4)();
melodyPattern([e5, cs5, e5, cs5], a4)();
melodyPattern([a5, cs5, a5, a5], a4)();
};
const melodySeq1 = () => {
melodyPattern([f5, d5], a4)();
simpleMelodyPattern([f5, g5, a5, a4])();
simpleMelodyPattern([
a5, bb4, d5, bb5, a5, bb4, d5, bb5,
g5, g4, c5, g4, e5, f5, g5, c5,
g5, a4, c5, a5, f5, a4, e5, c5,
f5, bb4, d5, bb4, d5, e5, f5, bb4,
f5, g4, bb4, g4, d5, e5, f5, g4
])();
melodyPattern([f5, cs5, e5, cs5, a5, cs5], a4)();
melodyPattern([a5, a5], cs5)();
};
const melodySeqEnd = simpleMelodyPattern([d5, a4, e5, f5]);
const bassPattern = simpleMelodyPattern([
d3, 0, 0, 0, 0, d3, e3, f3,
g3, 0, 0, 0, 0, g3, a3, bb3,
c4, 0, 0, 0, 0, bb3, a3, g3,
f3, 0, g3, 0, a3, 0, f3, 0,
bb3, 0, 0, 0, 0, c4, bb3, a3,
g3, 0, 0, 0, 0, a3, bb3, g3,
a3, 0, 0, 0, a3, 0, 0, 0,
a3, 0, g3, 0, f3, 0, e3, 0
]);
loop(() => {
melodySeq0();
melodySeq0();
melodySeq1();
melodySeq1();
melodySeqEnd();
melodySeqEnd();
melodySeqEnd();
simpleMelodyPattern([d5, 0, 0, 0])();
}, { name: 'melody', amp: 0.3 });
loop(() => {
sleep(32);
bassPattern();
bassPattern();
bassPattern();
simpleMelodyPattern([d3, 0, 0, 0, 0, 0, 0, 0])();
sleep(4);
}, { name: 'bass', amp: 0.5 });