screenshot.js

/* global THREE */

/*
This is an example of using only the core API (.viewer) to implement rendering a world and saving a screenshot of it
*/

global.THREE = require('three')
global.Worker = require('worker_threads').Worker
const { createCanvas } = require('node-canvas-webgl/lib')
const { Schematic } = require('prismarine-schematic')
const fs = require('fs').promises
const path = require('path')
const Vec3 = require('vec3').Vec3

const { Viewer, WorldView, getBufferFromStream } = require('../..').viewer

const main = async () => {
  const viewDistance = 4
  const width = 512
  const height = 512
  const version = '1.16.4'
  const World = require('prismarine-world')(version)
  const Chunk = require('prismarine-chunk')(version)
  const center = new Vec3(30, 90, 30)
  const canvas = createCanvas(width, height)
  const renderer = new THREE.WebGLRenderer({ canvas })
  const viewer = new Viewer(renderer)
  const data = await fs.readFile(path.join(__dirname, '../standalone/public/smallhouse1.schem'))
  const schem = await Schematic.read(data, version)

  const world = new World(() => new Chunk())

  await schem.paste(world, new Vec3(0, 60, 0))

  if (!viewer.setVersion(version)) {
    return false
  }

  // Load world
  const worldView = new WorldView(world, viewDistance, center)
  viewer.listen(worldView)

  viewer.camera.position.set(center.x, center.y, center.z)

  const point = new THREE.Vector3(0, 60, 0)

  viewer.camera.lookAt(point)

  await worldView.init(center)
  await viewer.world.waitForChunksToRender()
  renderer.render(viewer.scene, viewer.camera)

  const imageStream = canvas.createJPEGStream({
    bufsize: 4096,
    quality: 100,
    progressive: false
  })
  const buf = await getBufferFromStream(imageStream)
  await fs.mkdir(path.join(__dirname, 'screenshots/'), { recursive: true })
  await fs.writeFile(path.join(__dirname, 'screenshots/test.jpg'), buf)
  console.log('saved')
  process.exit(0)
}
main()