test.js

import assert from 'node:assert/strict'

const F2 = 0.5 * (Math.sqrt(3) - 1), G2 = (3 - Math.sqrt(3)) / 6
const GRAD2 = [[1,1],[-1,1],[1,-1],[-1,-1],[1,0],[-1,0],[0,1],[0,-1]]
function buildPermTable(seed) {
  const p = new Uint8Array(256); for (let i = 0; i < 256; i++) p[i] = i
  let s = seed | 0
  for (let i = 255; i > 0; i--) { s=(s*1664525+1013904223)>>>0; const j=s%(i+1); const tmp=p[i]; p[i]=p[j]; p[j]=tmp }
  const perm = new Uint8Array(512); for (let i=0;i<512;i++) perm[i]=p[i&255]; return perm
}
function simplex2(perm, x, y) {
  const s=(x+y)*F2, i=Math.floor(x+s), j=Math.floor(y+s), t=(i+j)*G2
  const x0=x-(i-t),y0=y-(j-t),i1=x0>y0?1:0,j1=x0>y0?0:1
  const x1=x0-i1+G2,y1=y0-j1+G2,x2=x0-1+2*G2,y2=y0-1+2*G2
  const ii=i&255,jj=j&255; let n=0
  for (const [dx,dy,ddx,ddy] of [[x0,y0,ii,jj],[x1,y1,ii+i1,jj+j1],[x2,y2,ii+1,jj+1]]) {
    const t2=0.5-dx*dx-dy*dy
    if (t2>=0) { const g=GRAD2[perm[ddx+perm[ddy&255]]&7]; n+=(t2*t2)*(t2*t2)*(g[0]*dx+g[1]*dy) }
  }
  return n*70
}
function fbm({seed,octaves,frequency,amplitude,gain,lacunarity,offset=0}) {
  const perms=Array.from({length:octaves},(_,i)=>buildPermTable((seed+i*73856093)>>>0))
  return (x,y)=>{ let v=0,amp=amplitude,freq=frequency; for (let i=0;i<octaves;i++){v+=amp*simplex2(perms[i],freq*x,freq*y);amp*=gain;freq*=lacunarity}; return v+offset }
}

let pass = 0, fail = 0
const _tests = []
function test(name, fn) { _tests.push({ name, fn }) }

test('FBM noise is deterministic', () => {
  const n = fbm({seed:42,octaves:4,frequency:0.1,amplitude:1,gain:0.5,lacunarity:2})
  assert.equal(n(1,2).toFixed(6), n(1,2).toFixed(6))
  assert.notEqual(n(1,2).toFixed(4), n(3,4).toFixed(4))
})

test('FBM seed isolation', () => {
  const n1 = fbm({seed:0,octaves:4,frequency:0.1,amplitude:1,gain:0.5,lacunarity:2})
  const n2 = fbm({seed:999,octaves:4,frequency:0.1,amplitude:1,gain:0.5,lacunarity:2})
  assert.notEqual(n1(1,1).toFixed(4), n2(1,1).toFixed(4))
})

test('FBM offset applied', () => {
  const n = fbm({seed:0,octaves:1,frequency:0.01,amplitude:0.001,gain:0.5,lacunarity:2,offset:5})
  assert(Math.abs(n(0,0) - 5) < 0.1, `expected ~5, got ${n(0,0)}`)
})

test('simplex2 output in expected range', () => {
  const perm = buildPermTable(0)
  for (let i = 0; i < 20; i++) {
    const v = simplex2(perm, i*0.3, i*0.7)
    assert(v >= -1 && v <= 1, `simplex2 out of range: ${v}`)
  }
})

test('world config aim_sillos scale is [1,1,1]', async () => {
  const src = await import('file:///C:/dev/devbox/spawnpoint/apps/world/index.js')
  const wd = src.default
  const sillos = wd.entities.find(e => e.id === 'env-sillos')
  assert(sillos, 'env-sillos not found')
  assert.deepEqual(sillos.scale, [1,1,1], `scale was ${JSON.stringify(sillos.scale)}`)
})


for (const { name, fn } of _tests) {
  try { await fn(); console.log('PASS', name); pass++ }
  catch(e) { console.error('FAIL', name, e.message); fail++ }
}
console.log(`\n${pass} passed, ${fail} failed`)
if (fail > 0) process.exit(1)