feuerwerk/tests/core/envelope.test.ts

/**
 * An Envelope (#335) shapes a note of an instrument: on the way of the sound it is its volume, and its
 * curve can move a number on the audio thread – the cutoff of a Filter, a Pitch, a Gain, a Mix, a
 * band of the EQ – from "from" at rest to "to" at the top.
 */
import { describe, expect, it } from 'vitest';
import { CreateAssetCommand, CreateSoundCommand } from '../../src/core/commands/assetCommands';
import { ConnectCommand } from '../../src/core/commands/graphCommands';
import { createEmptyGraph, type GraphNode } from '../../src/core/graph/Graph';
import { portsMeet } from '../../src/core/graph/NodeRegistry';
import { compileInstrument, instrumentSourcesOf } from '../../src/core/instrument/compile';
import { envelopeLevel, modCurve, releaseTime, SETTLE } from '../../src/core/instrument/envelope';
import { VELOCITY_PARAM } from '../../src/core/instrument/nodes';
import type { BehaviorAsset, InstrumentAsset } from '../../src/core/model/Asset';
import { compileSoundFx } from '../../src/core/soundfx/compile';
import { FLAT_Q, fxChainOf, type FxEnvelope, type FxPlan, passQ } from '../../src/core/soundfx/nodes';
import { graphEditor, makeProject } from '../helpers';

const FILE = `${'c3'.repeat(32)}.wav`;

/** An instrument with nothing in it, a Notes node and a Sample playing `FILE` on every note. */
function makeInstrument() {
  const f = makeProject();
  const command = new CreateAssetCommand('instrument', 'Pad');
  f.stack.execute(command);
  const instrument = command.asset as InstrumentAsset;
  instrument.graph = createEmptyGraph();
  const made = new CreateSoundCommand('Pad', FILE);
  f.stack.execute(made);
  const edit = graphEditor(f, instrument as unknown as BehaviorAsset);
  const notes = edit.addNode('InstrumentNotes');
  const sample = edit.addNode('InstrumentSample', { sound: made.asset.id });
  const output = edit.addNode('InstrumentOutput');
  edit.connect(notes, 'any', sample, 'trigger');
  const compile = () => compileInstrument(instrument.graph, 60, instrumentSourcesOf(f.project));
  return { ...f, instrument, edit, notes, sample, output, compile };
}

const ENVELOPE: FxEnvelope = { id: 'e', attack: 0.1, decay: 0.2, sustain: 0.5, release: 0.3 };

describe('the curve of an Envelope', () => {
  it('rises in a straight line, then falls towards the sustain, 60 dB of the way there by the end of the decay', () => {
    expect(envelopeLevel(ENVELOPE, 0)).toBe(0);
    expect(envelopeLevel(ENVELOPE, 0.05)).toBeCloseTo(0.5, 9);
    expect(envelopeLevel(ENVELOPE, 0.1)).toBeCloseTo(1, 9);
    expect(envelopeLevel(ENVELOPE, 0.3)).toBeCloseTo(0.5 + 0.5 / 1000, 9);
    expect(envelopeLevel(ENVELOPE, 10)).toBeCloseTo(0.5, 9);
    // Without an attack it starts at the top, without a decay it is at the sustain right after.
    expect(envelopeLevel({ ...ENVELOPE, attack: 0 }, 0.000001)).toBeCloseTo(1, 3);
    expect(envelopeLevel({ ...ENVELOPE, decay: 0 }, 0.1)).toBe(0.5);
    expect(Math.exp(-SETTLE)).toBeCloseTo(0.001, 9);
  });

  it('takes 10 ms to release at least, so a note does not click', () => {
    expect(releaseTime(ENVELOPE)).toBe(0.3);
    expect(releaseTime({ ...ENVELOPE, release: 0 })).toBe(0.01);
  });

  it('moves a number evenly, or in equal ratios, and below 0 stays where it rests', () => {
    const at = (curve: Float32Array, s: number) => curve[Math.round(((s + 1) / 2) * (curve.length - 1))]!;
    const even = modCurve({ envelope: ENVELOPE, from: 2, to: 10 }, false);
    expect([at(even, -1), at(even, 0), at(even, 0.5), at(even, 1)]).toEqual([2, 2, 6, 10]);
    const ratio = modCurve({ envelope: ENVELOPE, from: 200, to: 5000 }, true);
    expect(at(ratio, 0.5)).toBeCloseTo(1000, 1);
    // A ratio needs both ends above 0; otherwise it goes evenly.
    expect(at(modCurve({ envelope: ENVELOPE, from: 0, to: 1 }, true), 0.5)).toBe(0.5);
    const mapped = modCurve({ envelope: ENVELOPE, from: 0, to: 1 }, false, (mix) => 1 - mix);
    expect([at(mapped, 0), at(mapped, 1)]).toEqual([1, 0]);
  });
});

describe('a Filter', () => {
  it('has no bump at resonance 0 and rings towards 1; a band-pass gets narrower', () => {
    expect(passQ('lowpass', 0)).toBeCloseTo(FLAT_Q, 9);
    expect(passQ('highpass', 1)).toBe(20);
    expect(passQ('bandpass', 0)).toBeCloseTo(0.7, 9);
    expect(passQ('bandpass', 1)).toBeCloseTo(20, 9);
    expect(passQ('lowpass', 7)).toBe(20);
  });

  it('is an effect of a sound FX as well, its cutoff in Hz and its resonance as a Q', () => {
    const f = makeProject();
    const made = new CreateAssetCommand('soundfx', 'Muffle');
    f.stack.execute(made);
    const fx = made.asset as unknown as BehaviorAsset;
    const edit = graphEditor(f, fx);
    const input = edit.addNode('SoundFxInput');
    const filter = edit.addNode('SoundFxFilter', { filter: 'highpass', cutoff: 300, resonance: 1 });
    const output = edit.addNode('SoundFxOutput');
    edit.wire([
      [input, 'out', filter, 'in'],
      [filter, 'out', output, 'in'],
    ]);
    const plan = compileSoundFx((fx as unknown as { graph: never }).graph).compiled!;
    expect(fxChainOf(plan).stages).toEqual([{ kind: 'pass', filter: 'highpass', cutoff: 300, q: 20 }]);
  });
});

describe('an Envelope in an instrument', () => {
  it('on the way of the sound is its volume, its numbers held to their rows', () => {
    const f = makeInstrument();
    const envelope = f.edit.addNode('InstrumentEnvelope', { attack: 0.02, sustain: 3, release: -1 });
    f.edit.wire([
      [f.sample, 'out', envelope, 'in'],
      [envelope, 'out', f.output, 'in'],
    ]);
    const build = f.compile();
    expect(build.reason).toBe('');
    expect(fxChainOf(build.layers[0]!).stages).toEqual([
      { kind: 'envelope', envelope: { id: envelope.id, attack: 0.02, decay: 0.1, sustain: 1, release: 0 } },
    ]);
  });

  it('moves the cutoff of a Filter from "from" to "to", and its resonance as a Q', () => {
    const f = makeInstrument();
    const envelope = f.edit.addNode('InstrumentEnvelope', { from: 200, to: 5000 });
    const sweep = f.edit.addNode('InstrumentEnvelope', { decay: 1, from: 0, to: 1 });
    const filter = f.edit.addNode('SoundFxFilter');
    f.edit.wire([
      [f.sample, 'out', filter, 'in'],
      [envelope, 'value', filter, 'cutoff'],
      [sweep, 'value', filter, 'resonance'],
      [filter, 'out', f.output, 'in'],
    ]);
    const build = f.compile();
    // An Envelope moving numbers only shapes no sound, and nothing is missing for it.
    expect(build.problems).toEqual({});
    const [stage] = fxChainOf(build.layers[0]!).stages;
    expect(stage).toMatchObject({
      kind: 'pass',
      filter: 'lowpass',
      cutoff: 200,
      cutoffMod: { envelope: { id: envelope.id }, from: 200, to: 5000 },
      qMod: { envelope: { id: sweep.id, decay: 1 }, from: FLAT_Q, to: 20 },
    });
  });

  it('holds both ends to the row of the number it moves, and fills in what a note hands it', () => {
    const f = makeInstrument();
    const envelope = f.edit.addNode('InstrumentEnvelope', { from: 0, to: 30000 });
    const filter = f.edit.addNode('SoundFxFilter');
    f.edit.wire([
      [f.sample, 'out', filter, 'in'],
      [envelope, 'value', filter, 'cutoff'],
      [f.notes, 'velocity', envelope, 'sustain'],
      [filter, 'out', f.output, 'in'],
    ]);
    const chain = fxChainOf(f.compile().layers[0]!, { [VELOCITY_PARAM]: 0.25 });
    expect(chain.stages[0]).toMatchObject({
      cutoff: 20,
      cutoffMod: { from: 20, to: 20000, envelope: { sustain: 0.25 } },
    });
  });

  it('moves a Pitch on top of the one the way has, a Gain in its factor, a band and a Mix', () => {
    const f = makeInstrument();
    const envelope = f.edit.addNode('InstrumentEnvelope', { from: -12, to: 0 });
    const pitch = f.edit.addNode('SoundFxPitch');
    const gain = f.edit.addNode('SoundFxGain');
    const eq = f.edit.addNode('SoundFxEq');
    const mix = f.edit.addNode('SoundFxMix');
    f.edit.wire([
      [f.sample, 'out', pitch, 'in'],
      [envelope, 'value', pitch, 'semitones'],
      [pitch, 'out', gain, 'in'],
      [envelope, 'value', gain, 'gain'],
      [gain, 'out', eq, 'in'],
      [envelope, 'value', eq, 'mid'],
      [eq, 'out', mix, 'a'],
      [f.sample, 'out', mix, 'b'],
      [envelope, 'value', mix, 'mix'],
      [mix, 'out', f.output, 'in'],
    ]);
    const chain = fxChainOf(f.compile().layers[0]!);
    if (!('mix' in chain) || 'mix' in chain.a) throw new Error('a Mix of two ways');
    // The mix rests at "from", held to 0..1; at 0 it is not taken for "only a".
    expect(chain.mix).toBe(0);
    expect(chain.mixMod).toMatchObject({ from: 0, to: 0 });
    expect(chain.a.pitch).toBe(0);
    expect(chain.a.shifted).toBe(true);
    expect(chain.a.pitchMods).toMatchObject([{ from: -12, to: 0 }]);
    expect(chain.a.stages).toMatchObject([
      { kind: 'gain', mod: { from: 10 ** (-12 / 20), to: 1 } },
      { kind: 'filter', frequency: 1000, mod: { from: -12, to: 0 } },
    ]);
  });

  it('cannot move a number the audio thread does not hold, like the time of a Delay', () => {
    const f = makeInstrument();
    const envelope = f.edit.addNode('InstrumentEnvelope');
    const delay = f.edit.addNode('SoundFxDelay');
    const value = { type: 'envelope' as const };
    expect(portsMeet(value, { type: 'number', followsEnvelope: true })).toBe(true);
    expect(portsMeet(value, { type: 'number' })).toBe(false);
    expect(portsMeet(value, { type: 'any' })).toBe(false);
    expect(portsMeet({ type: 'number' }, { type: 'envelope' })).toBe(false);
    expect(() =>
      f.stack.execute(
        new ConnectCommand(
          f.instrument.id,
          { node: envelope.id, port: 'value' },
          { node: delay.id, port: 'time' },
        ),
      ),
    ).toThrow('Cannot connect envelope to number');
    // Saved that way anyhow, it says so rather than playing it.
    f.instrument.graph.edges.push({
      id: 'by-hand',
      from: { node: envelope.id, port: 'value' },
      to: { node: delay.id, port: 'time' },
    });
    f.edit.wire([
      [f.sample, 'out', delay, 'in'],
      [delay, 'out', f.output, 'in'],
    ]);
    expect(f.compile().problems[delay.id]).toBe('"Time" cannot follow an Envelope');
  });

  it('with its sound way connected on but nothing coming in, says so', () => {
    const f = makeInstrument();
    const envelope: GraphNode = f.edit.addNode('InstrumentEnvelope');
    f.edit.connect(envelope, 'out', f.output, 'in');
    expect(f.compile().problems[envelope.id]).toBe('Nothing comes in: connect it to a Sample');
  });

  it('leaves the plan of a note without one as it was', () => {
    const f = makeInstrument();
    f.edit.connect(f.sample, 'out', f.output, 'in');
    const plan: FxPlan = f.compile().layers[0]!;
    expect(plan.stages).toEqual([]);
  });
});