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

/**
 * A Saturation's node as a device (#396): every part on the plate and none over another, the wave
 * a sine at -12 dBFS comes out as, and the heat it glows with – hotter the harder it is driven.
 */
import { describe, expect, it } from 'vitest';
import { SATURATION_ROWS } from '../../src/core/soundfx/nodes';
import { SATURATION_TYPES } from '../../src/core/soundfx/saturation';
import { type Box, knobBox } from '../../src/editor/soundfx/hardwareView';
import {
  embersAt,
  emberCount,
  flicker,
  heatColor,
  heatOf,
  heatWord,
  idleSaturationKeys,
  MOST_EMBERS,
  SATURATION_KEYS,
  SATURATION_KNOBS,
  SATURATION_LAYOUT,
  SATURATION_PANEL,
  type SaturationValues,
  saturationTexts,
  saturationValues,
  typeCaption,
  waveTrace,
} from '../../src/editor/soundfx/saturationView';
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 <= SATURATION_PANEL.w && a.y + a.h <= SATURATION_PANEL.h;

const values = (over: Partial<SaturationValues> = {}): SaturationValues => ({
  ...saturationValues({}),
  ...over,
});

describe('the Saturation plate', () => {
  const L = SATURATION_LAYOUT;
  const screws = L.screws.map((s) => ({ x: s.x - 7, y: s.y - 7, w: 14, h: 14 }));
  // A lever's ball hangs 8 below its box when it is off.
  const lever = { ...L.autoGain, h: L.autoGain.h + 8 };
  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 };

  it('keeps the screen, the lever, the buttons and the knobs on the plate, clear of each other and the screws', () => {
    const parts: Box[] = [
      L.bezel,
      lever,
      L.typeGroup,
      ...L.types,
      ...SATURATION_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 button for every type, named by a word of its own', () => {
    expect(L.types).toHaveLength(SATURATION_TYPES.length);
    const names = SATURATION_TYPES.map((t) => typeCaption(t.value));
    expect(new Set(names).size).toBe(names.length);
    expect(typeCaption('hard')).toBe('HARD');
    expect(typeCaption('soft')).toBe('SOFT');
  });
});

describe('the Saturation knobs', () => {
  const position = (key: 'output' | 'drive', value: number) => {
    const row = SATURATION_ROWS[key];
    return knobPosition(value, { min: row.min!, max: row.max!, step: row.step!, ...SATURATION_KNOBS[key] });
  };

  it('turns the output round 0 straight up, the drive from its start', () => {
    expect(position('output', 0)).toBeCloseTo(0.5);
    expect(position('drive', 0)).toBe(0);
    expect(position('drive', 24)).toBeCloseTo(0.5);
  });

  it('names the tone by the cutoff it opens to and the output with its sign', () => {
    expect(SATURATION_KNOBS.tone.format(1)).toBe('20 kHz');
    expect(SATURATION_KNOBS.tone.format(0)).toBe('1 kHz');
    expect(SATURATION_KNOBS.output.format(3.5)).toBe('+3.5 dB');
    expect(SATURATION_KNOBS.output.format(-6)).toBe('-6 dB');
  });

  it('greys everything but the wet at wet 0, nothing else', () => {
    expect([...idleSaturationKeys(values({ mix: 0 }))].sort()).toEqual(
      ['autoGain', 'drive', 'output', 'tone', 'type'].sort(),
    );
    expect(idleSaturationKeys(values({ autoGain: false })).size).toBe(0);
  });
});

describe('the Saturation screen', () => {
  it('lets the sine through as it is at wet 0', () => {
    const trace = waveTrace(values({ drive: 48, mix: 0 }));
    trace.out.forEach((v, i) => expect(v).toBeCloseTo(trace.dry[i]!, 9));
    expect(saturationTexts(values({ mix: 0 }), trace)).toEqual({ auto: 'DRY', peak: 'PEAK -12 dBFS' });
  });

  it('bends a sine into a square at full drive, kept as loud by auto-gain', () => {
    const trace = waveTrace(values({ type: 'hard', drive: 48 }));
    const flat = trace.out.filter((v) => Math.abs(Math.abs(v) - trace.peak) < 1e-6).length;
    expect(flat / trace.out.length).toBeGreaterThan(0.9);
    // As loud by its RMS as the sine going in.
    const rms = (xs: number[]) => Math.sqrt(xs.reduce((s, v) => s + v * v, 0) / xs.length);
    expect(20 * Math.log10(rms(trace.out) / rms(trace.dry))).toBeCloseTo(0, 0);
  });

  it('takes out the DC a bent half leaves, as the node does', () => {
    const trace = waveTrace(values({ type: 'rectify', drive: 24 }));
    const mean = trace.out.slice(0, -1).reduce((s, v) => s + v, 0) / (trace.out.length - 1);
    expect(Math.abs(mean)).toBeLessThan(1e-9);
  });

  it('puts the output alone after the curve without auto-gain', () => {
    const trace = waveTrace(values({ autoGain: false, output: -6 }));
    expect(trace.gain).toBe(-6);
    expect(trace.auto).toBeNull();
    expect(saturationTexts(values({ autoGain: false }), trace).auto).toBe('AUTO-GAIN OFF');
  });
});

describe('the Saturation heat', () => {
  it('runs hotter with the drive and only as far as the wet is heard', () => {
    expect(heatOf(values({ drive: 0 }))).toBe(0);
    expect(heatOf(values({ drive: 12 }))).toBeCloseTo(0.25);
    expect(heatOf(values({ drive: 48 }))).toBe(1);
    expect(heatOf(values({ drive: 48, mix: 0.5 }))).toBeCloseTo(0.5);
    expect(heatOf(values({ drive: 48, mix: 0 }))).toBe(0);
  });

  it('goes from cold steel through ember red to white', () => {
    const red = (c: number) => (c >> 16) & 0xff;
    const blue = (c: number) => c & 0xff;
    expect(blue(heatColor(0))).toBeGreaterThan(red(heatColor(0)));
    expect(red(heatColor(0.3))).toBeGreaterThan(blue(heatColor(0.3)) + 100);
    expect(heatColor(1)).toBe(0xfff4dc);
    expect([0, 0.2, 0.4, 0.6, 0.9].map(heatWord)).toEqual(['COLD', 'WARM', 'HOT', 'GLOWING', 'WHITE HOT']);
  });

  it('sends up more embers the hotter it runs, none while it is only warm', () => {
    expect(emberCount(0.1)).toBe(0);
    expect(emberCount(0.5)).toBeGreaterThan(emberCount(0.3));
    expect(emberCount(1)).toBe(MOST_EMBERS);
  });

  it('lets the embers rise by the clock, on the screen and the same every time', () => {
    const now = embersAt(0.8, 3);
    const later = embersAt(0.8, 3.1);
    expect(embersAt(0.8, 3)).toEqual(now);
    for (const e of [...now, ...later]) {
      expect(e.x).toBeGreaterThanOrEqual(0);
      expect(e.x).toBeLessThanOrEqual(1);
      expect(e.y).toBeGreaterThan(0);
      expect(e.y).toBeLessThanOrEqual(1);
      expect(e.alpha).toBeGreaterThanOrEqual(0);
      expect(e.alpha).toBeLessThanOrEqual(1);
    }
    // Most go up between two frames; one that went round starts at the bottom again.
    const rose = now.filter((e, i) => later[i]!.y < e.y).length;
    expect(rose).toBeGreaterThan(now.length * 0.8);
  });

  it('flickers within 8 % either way', () => {
    for (let t = 0; t < 10; t += 0.037) {
      expect(flicker(t)).toBeGreaterThanOrEqual(0.92);
      expect(flicker(t)).toBeLessThanOrEqual(1.08);
    }
    expect(flicker(1)).not.toBe(flicker(1.05));
  });
});