​

let elevation = -300

let groundElevation = 200

let treeLeavesRadius = 50

let treeLeavesHeight = -2.5 * treeLeavesRadius

let treeTrunkWidth = 0.25 * treeLeavesRadius

let treeTrunkHeight = 0.2 * treeLeavesHeight

let treeTrunkOffset = -((treeLeavesHeight / 2) + (treeTrunkHeight / 2))

let grassImage

let treeImage

let trunkImage

let moonImage

let starImage

let starAngle = 0

let moonAngle = 0

let ufoAngle = 0

let speed = 1

let gravity = 0.09

let gravity2 = 0.03

let descentStage = 0

​

let rocketColors = ['orange', 'yellow', 'red']

​

function preload() {

  grassImage = loadImage('grass.png')

  treeImage = loadImage('xmas.jpg')

  trunkImage = loadImage('wood.jpg')

  starImage = loadImage('stars.jpg')

  moonImage = loadImage('moon.jpg')

  rocketImage = loadImage('explosion.jpg')

}

​

function setup() {

  createCanvas(700, 700, WEBGL)

  noStroke()

}

​

function draw() {

  orbitControl()

  background('midnightblue');

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

  pointLight(255, 255, 255, 0, elevation - 30, 0)

  drawStars()

  drawGround()

  drawUfo()

  drawForest()

  drawMoon()

  moveUfo()

}

​

function moveUfo() {

  elevation += speed

  speed += gravity

  if (elevation >= 100 && descentStage === 0) {

    speed = 1

    speed -= 5

    descentStage = 1

  } else if (descentStage === 1 && speed >= 0) {

    speed = 1

    gravity = 0

  }

​

  if (elevation >= 165) {

    elevation = 165

    noLoop()

  }

}

​

function drawGround() {

  push()

  texture(grassImage)

  spotLight(255, 255, 255, 0, elevation, 0, 0, 1, 0, Math.PI / 6, 3)

  translate(0, 200, 0)

  rotateX(Math.PI / 2)

  plane(550, 550)

  pop()

}

​

function drawStars() {

  push()

  rotateZ(starAngle)

  translate(0, -200, -1000)

  texture(starImage)

  plane(width * 8, height * 3)

  pop()

  starAngle += 0.0004

}

​

function drawMoon() {

  push()

  translate(width * -0.6, height * -0.6, -500)

  rotateY(moonAngle)

  texture(moonImage)

  sphere()

  pop()

  moonAngle += 0.003

}

​

function drawTree(x, y, z) {

  push()

  translate(x, y, z)

  texture(treeImage)

  cone(treeLeavesRadius, treeLeavesHeight)

  translate(0, treeTrunkOffset, 0)

  texture(trunkImage)

  cylinder(treeTrunkWidth, treeTrunkHeight)

  pop()

}

​

function drawForest() {

  const treeElevation = groundElevation + (treeLeavesHeight / 2) + treeTrunkHeight

  drawTree(width * 0.25, treeElevation, -110)

  drawTree(width * -0.25, treeElevation, -110)

  drawTree(width * 0.25, treeElevation, 110)

  drawTree(width * -0.25, treeElevation, 110)

 }

​

function drawUfo() {

  push()

  rotateY(ufoAngle)

  drawUfoBody()

  drawUfoTop()

  drawUfoTailLight()

  drawUfoRunningLights()

  drawUfoLandingFin()

  drawUfoBoosters()

  pop()

  ufoAngle += 0.015

}

​

function drawUfoBody() {

  push()

  translate(0, elevation, 0)

  specularMaterial(250, 250, 250, 1000)

  shininess(20)

  ellipsoid(80, 20, 80)

  pop()

}

​

function drawUfoTop() {

  push()

  translate(0, elevation - 20, 0)

  specularMaterial(250, 250, 250, 1000)

  shininess(20)

  ellipsoid(40, 20, 40)

  pop()

}

​

function drawUfoTailLight() {

  push()

  translate(0, elevation + 20, 0)

  emissiveMaterial('white')

  sphere(5)

  pop()

}

​

function drawUfoRunningLights() {

  push()

  for (let theta = 0; theta < 360; theta += Math.PI / 8) {

    push()

    emissiveMaterial('white')

    translate(76 * cos(theta), elevation, 76 * sin(theta))

    sphere(5)

    pop()

  }

  pop()

}

​

function drawUfoLandingFin() {

  push()

  for (let theta = 0; theta < 360; theta += Math.PI / 1.5) {

    push()

    translate(50 * cos(theta), elevation + 18, 50 * sin(theta))

    specularMaterial(250, 250, 250, 1000)

    shininess(20)

    cylinder(10, 36)

    pop()

  }

  pop()

​

​

}

​

function drawUfoBoosters() {

  if (descentStage === 1) {

    for (let theta = 0; theta < 360; theta += Math.PI / 1.5) {

      push()

      translate(50 * cos(theta), elevation + 46, 50 * sin(theta))

      emissiveMaterial(random(rocketColors))

      cone(10, 20)

      pop()

    }

  }

}

​