feuerwerk/tests/editor/crusher-view.test.ts

/**
 * A Bitcrusher's node as a device (#399): every part on the plate and none over another, the bits
 * it keeps, and the screen – what a sine comes out as, worked out by the node's own crush, so
 * the steps and holds drawn are the ones heard.
 */
import { describe, expect, it } from 'vitest';
import { Crusher, crushSteps } from '../../src/core/soundfx/crusher';
import { CRUSH_ROWS } from '../../src/core/soundfx/nodes';
import {
  bitLampsLit,
  cellOf,
  CRUSH_KEYS,
  CRUSH_KNOBS,
  type CrushValues,
  CRUSHER_LAYOUT,
  CRUSHER_PANEL,
  crushOf,
  crushTexts,
  crushTrace,
  crushValues,
  crushWord,
  idleCrushKeys,
  LEAST_HOLDS,
  SCREEN_RATE,
  screenSpan,
} from '../../src/editor/soundfx/crusherView';
import { type Box, knobBox } from '../../src/editor/soundfx/hardwareView';
import { knobPosition } from '../../src/ui/knob';

const overlap = (a: Box, b: Box) => a.x < b.x + b.w && b.x < a.x + a.w && a.y < b.y + b.h && b.y < a.y + a.h;
const inside = (a: Box) =>
  a.x >= 0 && a.y >= 0 && a.x + a.w <= CRUSHER_PANEL.w && a.y + a.h <= CRUSHER_PANEL.h;

const values = (over: Partial<CrushValues> = {}): CrushValues => ({ ...crushValues({}), ...over });

describe('the Bitcrusher plate', () => {
  const L = CRUSHER_LAYOUT;
  const screws = L.screws.map((s) => ({ x: s.x - 7, y: s.y - 7, w: 14, h: 14 }));
  const lamp = { x: L.lamp.x - L.lamp.r, y: L.lamp.y - L.lamp.r, w: 2 * L.lamp.r, h: 2 * L.lamp.r };
  const lamps = L.bitLamps.reduce((all, b) => ({ ...all, w: b.x + b.w - all.x }), { ...L.bitLamps[0]! });

  it('keeps the screen, the lamps and the knobs on the plate, clear of each other and the screws', () => {
    const parts: Box[] = [L.bezel, lamps, ...CRUSH_KEYS.map((key) => knobBox(L.knobs[key])), lamp, L.title];
    for (const part of parts) {
      expect(inside(part)).toBe(true);
      for (const screw of screws) expect(overlap(part, screw)).toBe(false);
    }
    for (let i = 0; i < parts.length; i++)
      for (let j = i + 1; j < parts.length; j++) expect(overlap(parts[i]!, parts[j]!)).toBe(false);
  });

  it('has a lamp for every bit, none over another', () => {
    expect(L.bitLamps).toHaveLength(CRUSH_ROWS.bits.max!);
    for (let i = 1; i < L.bitLamps.length; i++)
      expect(L.bitLamps[i]!.x).toBeGreaterThan(L.bitLamps[i - 1]!.x + L.bitLamps[i - 1]!.w);
  });

  it('lights the bits kept, the highest first, part of one for a fraction', () => {
    expect(bitLampsLit(16).every((share) => share === 1)).toBe(true);
    expect(bitLampsLit(8)).toEqual([...Array<number>(8).fill(1), ...Array<number>(8).fill(0)]);
    expect(bitLampsLit(3.5).slice(0, 5)).toEqual([1, 1, 1, 0.5, 0]);
    expect(bitLampsLit(1).filter((share) => share > 0)).toEqual([1]);
  });
});

describe('the Bitcrusher knobs', () => {
  const position = (key: 'bits' | 'rate', value: number) => {
    const row = CRUSH_ROWS[key];
    return knobPosition(value, { min: row.min!, max: row.max!, step: row.step!, ...CRUSH_KNOBS[key] });
  };

  it('turns the bits evenly and puts 8 kHz just past the middle of the rate', () => {
    expect(position('bits', 8.5)).toBeCloseTo(0.5);
    expect(position('rate', 8000)).toBeGreaterThan(0.5);
    expect(position('rate', 8000)).toBeLessThan(0.6);
  });

  it('names the bits and the rate as they are heard', () => {
    expect(CRUSH_KNOBS.bits.format(8)).toBe('8 bit');
    expect(CRUSH_KNOBS.bits.format(3.5)).toBe('3.5 bit');
    expect(CRUSH_KNOBS.rate.format(8000)).toBe('8 kHz');
    expect(CRUSH_KNOBS.rate.format(300)).toBe('300 Hz');
  });

  it('greys the bits and the rate at wet 0, nothing else', () => {
    expect([...idleCrushKeys(values({ mix: 0 }))].sort()).toEqual(['bits', 'rate']);
    expect(idleCrushKeys(values()).size).toBe(0);
  });
});

describe('the Bitcrusher screen', () => {
  it('comes out as the node’s own worklet makes it, the wet blended in', () => {
    for (const over of [{}, { bits: 3, rate: 4000, mix: 0.4 }, { bits: 1.5, rate: 300 }]) {
      const v = values(over);
      const trace = crushTrace(v);
      const heard = new Float32Array(trace.dry.length);
      new Crusher(SCREEN_RATE).render(
        [trace.dry],
        [heard],
        Float32Array.of(v.bits),
        Float32Array.of(v.rate),
        Float32Array.of(v.mix),
      );
      trace.out.forEach((x, i) => expect(x).toBeCloseTo(heard[i]!, 6));
    }
  });

  it('cuts the sine into the holds of the rate, each one level the bits round it to', () => {
    const v = values({ bits: 4, rate: 8000 });
    const trace = crushTrace(v);
    const steps = crushSteps(4);
    // 8 kHz at 48 kHz: a hold every 6 samples. The first is one longer, as in the worklet: six
    // sixths add up to just under 1 there.
    const widths = trace.holds.map((h) => h.to - h.from);
    expect(widths[0]).toBe(7);
    expect(widths.slice(1, -1).every((w) => w === 6)).toBe(true);
    for (const hold of trace.holds) {
      expect(hold.level).toBeCloseTo(Math.round(trace.dry[hold.from]! * steps) / steps, 6);
      for (let i = hold.from; i < hold.to; i++) expect(trace.crushed[i]).toBe(hold.level);
    }
    expect(trace.step).toBe(1 / steps);
  });

  it('holds nothing at the rate of the context, and shows enough holds where the rate is low', () => {
    const fine = crushTrace(values({ rate: 48000 }));
    expect(fine.holds).toHaveLength(fine.dry.length);
    expect(screenSpan(8000)).toBeCloseTo(2 / 440);
    expect(screenSpan(300)).toBeCloseTo(LEAST_HOLDS / 300);
    expect(crushTrace(values({ rate: 300 })).holds).toHaveLength(LEAST_HOLDS);
  });

  it('draws a hold as a cell where its pixels allow, as a bar where the steps are fine, never a wall', () => {
    expect(cellOf(15, 16)).toEqual({ gap: 1, h: 14 });
    expect(cellOf(9, 0.6)).toEqual({ gap: 0, h: 2 });
    // One bit's levels are a screen apart: a bar on each.
    expect(cellOf(3.7, 64)).toEqual({ gap: 0, h: 7.4 });
    expect(cellOf(45, 64)).toEqual({ gap: 1, h: 62 });
  });

  it('says the noise the bits leave and where the rate folds back, nothing of it when dry', () => {
    const v = values();
    expect(crushTexts(v, crushTrace(v))).toEqual({
      noise: 'NOISE -50 dB',
      fold: 'FOLDS AT 4 kHz',
      span: '4.5 ms',
    });
    const dry = values({ mix: 0 });
    expect(crushTexts(dry, crushTrace(dry))).toMatchObject({ noise: 'DRY', fold: '' });
  });
});

describe('how crushed a Bitcrusher is', () => {
  it('takes whichever of the bits and the rate crushes more, as far as the wet is heard', () => {
    expect(crushOf(values({ bits: 16, rate: 48000 }))).toBe(0);
    expect(crushOf(values({ bits: 1 }))).toBe(1);
    expect(crushOf(values({ bits: 16, rate: 100 }))).toBeCloseTo(1);
    expect(crushOf(values({ bits: 1, mix: 0.5 }))).toBeCloseTo(0.5);
    expect(crushOf(values({ mix: 0 }))).toBe(0);
  });

  it('names it from clean to broken', () => {
    expect([0, 0.2, 0.5, 0.7, 0.9].map(crushWord)).toEqual([
      'CLEAN',
      'GRITTY',
      'CRUNCHY',
      'CRUSHED',
      'BROKEN',
    ]);
    expect(crushWord(crushOf(values()))).toBe('CRUNCHY');
  });
});