const groundElevation = 100

​

function setup() {

  createCanvas(500, 500, WEBGL);

  noStroke()

}

​

function draw() {

  directionalLight(255, 255, 255, 1, 1, -1)

  spotLight(255, 255, 0, ufo.x, ufo.y, ufo.z, 0, 1, 0, radians(30), 3)

  drawBackground()

  drawGround()

  drawUfo()

  moveUfo()

}

​

function drawGround() {

  push()

  fill('lightgreen')

  translate(0, 100, 0)

  rotateX(radians(90))  

  plane(900, 550)  

  pop()

}

​

function drawBackground() {

  background('midnightblue');

}

​

function drawUfo() {

  push()

  translate(ufo.x, ufo.y, ufo.z)

  rotateY(ufo.spin)

  ellipsoid(100, 20, 100)

  translate(0, -15, 0)

  sphere(30)

  translate(0, 35, 0)

  emissiveMaterial('white')

  sphere(10)

  pop()

}

​

function moveUfo() {

  ufo.spin += 0.01

  if (ufo.z < 0) {

    ufo.z += 1

  } else if (ufo.y < groundElevation-20) {

    ufo.y += 1

  } else {

    noLoop()

  }

}

​