music-video-gen/metabolism/test/rock.test.js

// M2.8 — rock: the inert resource. It is scattered at the world's birth,
// dropped and shattered by the song, impassable to the population, and
// quarried by builders — carried, walled, ground into soil.

import { test } from 'node:test';
import assert from 'node:assert/strict';
import { readFileSync } from 'node:fs';
import { fileURLToPath } from 'node:url';
import { resolve, dirname } from 'node:path';
import { analyse } from '../src/audio/analyse.js';
import { decodeWav, mono } from '../src/audio/wav.js';
import { buildSong } from '../src/song/song.js';
import { Run } from '../src/film.js';
import { OP, S_ROCK, A_DIG, A_BUILD } from '../src/song/strains.js';

const HERE = dirname(fileURLToPath(import.meta.url));
const BANK = resolve(HERE, '../..', 'flow-state/test/songs');

function load(name, seed = 12345) {
    const wav = decodeWav(readFileSync(resolve(BANK, `${name}.wav`)));
    return buildSong(analyse(mono(wav.channels), wav.sampleRate), seed);
}

function run(name, seed = 12345, field = 64) {
    const song = load(name, seed);
    const r = new Run(song, { fps: 30, seed, width: 240, height: 135, field, genesis: 0 });
    return r;
}

const rockMass = (w) => {
    let s = 0;
    for (let i = 0; i < w.n; i++) s += w.rock[i];
    return s;
};
const maskedCells = (w) => {
    let s = 0;
    for (let i = 0; i < w.n; i++) s += w.rockMask[i];
    return s;
};

test('the world is born with stone in it (deterministically)', () => {
    const a = run('drone').world;
    const b = run('drone').world;
    assert.ok(rockMass(a) > 5, `scatter should hold stone (${rockMass(a).toFixed(1)})`);
    assert.ok(maskedCells(a) > 0, 'some ground is impassable from birth');
    assert.deepEqual(Array.from(a.rock), Array.from(b.rock));
});

test('the song drops rock on heavy hits and shatters it on high ones', () => {
    const live = run('runner').world;
    const mute = run('runner').world;
    mute.program.rock.drop = 0;
    mute.program.rock.shatter = 0;
    for (let f = 0; f < 600; f++) { live.step(); mute.step(); }
    assert.ok(rockMass(live) > rockMass(mute) * 1.3,
        `rockfall should outpace a mute sky (live ${rockMass(live).toFixed(1)} vs ${rockMass(mute).toFixed(1)})`);
});

test('rock is a wall: the population cannot cross it', () => {
    const w = run('drone').world;
    const F = w.field;
    // A solid vertical wall of stone down the middle, north to south.
    for (let y = 0; y < F; y++) {
        for (let x = 30; x < 34; x++) w.rock[y * F + x] = 1.5;
    }
    w.refreshRockMask();
    // A crowd planted on the west side, food on both sides so the only
    // reason not to spread east is the wall.
    for (let y = 8; y < 56; y++) {
        for (let x = 4; x < 26; x++) {
            const i = y * F + x;
            for (let s = 0; s < w.m; s++) w.pop[s][i] = 2;
            w.alleg[0][i] = 2 * w.m;
            w.resource[i] = 1.2;
        }
        for (let x = 40; x < 60; x++) w.resource[y * F + x] = 1.2;
    }
    w.bodies[0].cx = 0.2; w.bodies[0].cy = 0.5; w.bodies[0].alive = true;
    if (!w.aliveBodies.includes(0)) w.aliveBodies.push(0);
    w.recount();

    for (let f = 0; f < 300; f++) w.step();

    let east = 0;
    for (let y = 0; y < F; y++) {
        for (let x = 34; x < F; x++) east += w.density[y * F + x];
    }
    assert.ok(east < w.count * 0.02,
        `the wall must hold (${east.toFixed(1)} of ${w.count.toFixed(0)} leaked east)`);
});

test('builders quarry: rock goes down, soil and burden appear', () => {
    const w = run('dusk').world;
    const F = w.field;
    // Every strain digs where rock lies.
    for (const s of w.strains) {
        s.code = [
            [OP.SENSE, 4, S_ROCK, 1],
            [OP.IFGT, 4, 0.05, 3],
            [OP.HALT],
            [OP.ACT, A_DIG, 4, 1],
            [OP.HALT],
        ];
    }
    // A rich seam under the crowd.
    for (let y = 20; y < 40; y++) {
        for (let x = 20; x < 40; x++) {
            const i = y * F + x;
            w.rock[i] = 1.4;
            for (let s = 0; s < w.m; s++) w.pop[s][i] = 3;
            w.alleg[0][i] = 3 * w.m;
        }
    }
    w.refreshRockMask();
    w.bodies[0].alive = true; w.bodies[0].cx = 0.45; w.bodies[0].cy = 0.45;
    if (!w.aliveBodies.includes(0)) w.aliveBodies.push(0);
    w.recount();

    const before = rockMass(w);
    let foodBefore = 0;
    for (let i = 0; i < w.n; i++) foodBefore += w.resource[i];
    for (let f = 0; f < 120; f++) w.step();
    const after = rockMass(w);
    let foodAfter = 0;
    for (let i = 0; i < w.n; i++) foodAfter += w.resource[i];
    let carry = 0;
    for (let s = 0; s < w.m; s++) for (let b = 0; b < w.fc; b++) carry += w.carry[s * w.fc + b];

    assert.ok(after < before - 1, `quarries must open (${before.toFixed(1)} → ${after.toFixed(1)})`);
    assert.ok(carry > 0.2, `the burden must be carried (${carry.toFixed(2)})`);
    assert.ok(foodAfter > foodBefore, `grinding yields soil (${foodBefore.toFixed(1)} → ${foodAfter.toFixed(1)})`);
});

test('builders build: carried rock rises as walls', () => {
    const w = run('dusk').world;
    // Every strain builds.
    for (const s of w.strains) {
        s.code = [
            [OP.SET, 4, 1],
            [OP.ACT, A_BUILD, 4, 1],
            [OP.HALT],
        ];
    }
    // A loaded block in the middle of open ground.
    const F = w.field;
    const b = w.coarseOf[30 * F + 30];
    for (let s = 0; s < w.m; s++) w.carry[s * w.fc + b] = 5;
    const before = rockMass(w);
    for (let f = 0; f < 60; f++) w.step();
    const after = rockMass(w);
    assert.ok(after > before + 0.5,
        `carried rock must rise (${before.toFixed(2)} → ${after.toFixed(2)})`);
});