unreal.js rotating box

rotating-box.js

// Loads into Unreal, renders accordingly. 

GWorld.GetAllActorsOfClass(Light).OutActors.map(l => l.DestroyActor())

function light(color) {
  let actor = new PointLight(GWorld)
  actor.LightComponent.SetMobility('Movable')
  actor.LightComponent.Intensity = 1000
  actor.LightComponent.SetLightColor(color)
  return actor
}

function box(p,size,color) {
  let actor = new StaticMeshActor(GWorld,p)
  let smc = actor.StaticMeshComponent
  smc.SetMobility('Movable')
  smc.SetStaticMesh(StaticMesh.Load('/Engine/BasicShapes/Cube'))
  let mtrl = Material.Load('/Game/Color')
  let mi = KismetMaterialLibrary.CreateDynamicMaterialInstance(GWorld,mtrl)
  mi.SetVectorParameterValue('color',color)
  smc.SetMaterial(0,mi)
  actor.SetActorScale3D(size)
  return actor
}

function bg(p) {
  let size = 1000
  let boxsize = 100
  let scale = size/boxsize
  p = Vector(p)
  // back
  box(p.Add_VectorVector({X:size / 2,Z:size / 2}),{X:1,Y:scale,Z:scale},{R:0.5,G:0.7})
  // left
  box(p.Add_VectorVector({Y:-size / 2,Z:size / 2}),{X:scale,Y:1,Z:scale},{B:1})
  // floor
  box(p,{X:scale,Y:scale,Z:1},{R:1})

  const N = 10
  const s = 0.04
  _.range(N).forEach(y => {
    _.range(N).forEach(x => {
      let a = box(p.Add_VectorVector({Y:(y - N/2) * 50, Z: x * 50}),{X:s,Y:s,Z:s},{R:1,G:1,B:1})
      a.SetActorRotation({Yaw:Math.random() * 360, Pitch:Math.random() * 180})
    })
  })
}

function skel(p) {
  let resource = SkeletalMesh.Load('/Game/Mannequin/Character/Mesh/SK_Mannequin')
  let actor = new SkeletalMeshActor(GWorld,Vector(p).Add_VectorVector({Z:50}))
  actor.SkeletalMeshComponent.SetSkeletalMesh(resource)
  actor.SetActorRotation({Yaw:90})
}

function rotate(actor,opts) {
  function tick() {
    if (!actor.IsValid()) return
    let rad = $time * opts.k
    let r = opts.r
    let p = Vector({Y:Math.cos(rad) * r, Z:Math.sin(rad) * r}).Add_VectorVector(opts.p)
    actor.SetActorLocation(p)
    process.nextTick(tick)
  }
  tick()
}

rotate(light({R:1}),{k:1.8,r:150,p:{X:400,Y:-100,Z:100}})
rotate(light({G:1}),{k:1.5,r:30,p:{X:400,Z:150}})
rotate(light({B:1}),{k:0.1,r:230,p:{X:400,Z:250}})
bg({X:400,Z:-150,Y:-100})
skel({X:400,Z:-150,Y:-100})