Error in Voxel Generation

Questions
1

Heyo! I followed the Voxel Geometry three.js tutorial. Nothing shows up when I run the code. I know its not my host, because ct8.pl supports three.js

<head>
  <style>
    html, body {
  height: 100%;
  margin: 0;
}
#c {
  width: 100%;
  height: 100%;
  display: block;
}

 </style>
  </head>
<canvas id="c"></canvas>
  <script  type="importmap">{
  "imports": {
    "three": "https://threejs.org/build/three.module.js",
    "three/addons/": "https://threejs.org/examples/jsm/"
  }
}</script><!-- Remove this when import maps will be widely supported -->
<script async src="https://unpkg.com/es-module-shims@1.3.6/dist/es-module-shims.js"></script>
<script>
import * as THREE from 'three';
import {OrbitControls} from 'three/addons/controls/OrbitControls.js';

function main() {
  const canvas = document.querySelector('#c');
  const renderer = new THREE.WebGLRenderer({canvas});

  const cellSize = 256;

  const fov = 75;
  const aspect = 2;  // the canvas default
  const near = 0.1;
  const far = 1000;
  const camera = new THREE.PerspectiveCamera(fov, aspect, near, far);
  camera.position.set(-cellSize * .3, cellSize * .8, -cellSize * .3);

  const controls = new OrbitControls(camera, canvas);
  controls.target.set(cellSize / 2, cellSize / 3, cellSize / 2);
  controls.update();

  const scene = new THREE.Scene();
  scene.background = new THREE.Color('lightblue');

  {
    const color = 0xFFFFFF;
    const intensity = 1;
    const light = new THREE.DirectionalLight(color, intensity);
    light.position.set(-1, 2, 4);
    scene.add(light);
  }

  const cell = new Uint8Array(cellSize * cellSize * cellSize);
  for (let y = 0; y < cellSize; ++y) {
    for (let z = 0; z < cellSize; ++z) {
      for (let x = 0; x < cellSize; ++x) {
        const height = (Math.sin(x / cellSize * Math.PI * 4) + Math.sin(z / cellSize * Math.PI * 6)) * 20 + cellSize / 2;
        if (height > y && height < y + 1) {
          const offset = y * cellSize * cellSize +
                       z * cellSize +
                       x;
          cell[offset] = 1;
        }
      }
    }
  }

  const geometry = new THREE.BoxGeometry(1, 1, 1);
  const material = new THREE.MeshPhongMaterial({color: 'green'});

  for (let y = 0; y < cellSize; ++y) {
    for (let z = 0; z < cellSize; ++z) {
      for (let x = 0; x < cellSize; ++x) {
        const offset = y * cellSize * cellSize +
                       z * cellSize +
                       x;
        const block = cell[offset];
        if (block) {
          const mesh = new THREE.Mesh(geometry, material);
          mesh.position.set(x, y, z);
          scene.add(mesh);
        }
      }
    }
  }

  function resizeRendererToDisplaySize(renderer) {
    const canvas = renderer.domElement;
    const width = canvas.clientWidth;
    const height = canvas.clientHeight;
    const needResize = canvas.width !== width || canvas.height !== height;
    if (needResize) {
      renderer.setSize(width, height, false);
    }
    return needResize;
  }

  let renderRequested = false;

  function render() {
    renderRequested = undefined;

    if (resizeRendererToDisplaySize(renderer)) {
      const canvas = renderer.domElement;
      camera.aspect = canvas.clientWidth / canvas.clientHeight;
      camera.updateProjectionMatrix();
    }

    controls.update();
    renderer.render(scene, camera);
  }
  render();

  function requestRenderIfNotRequested() {
    if (!renderRequested) {
      renderRequested = true;
      requestAnimationFrame(render);
    }
  }

  controls.addEventListener('change', requestRenderIfNotRequested);
  window.addEventListener('resize', requestRenderIfNotRequested);
}

main();
</script>

Thanks, 4fr

2

Try to add type module to the script tag, like so:

<script type="module">
import * as THREE from 'three'

instead of

<script>
import * as THREE from 'three';

otherwise your code works for me

image

it will also be better if you put your html content inside body tag:

...
</head>
<body>
<canvas id="c"></canvas>
...
main();
</script>
</body>
1 Like
3 
<html>
  <head>
    <title>cube.playground</title>
  <style>
    html, body {
  height: 100%;
  margin: 0;
}
#c {
  width: 100%;
  height: 100%;
  display: block;
}

 </style>
  </head>
  <body>
    <canvas id="c"></canvas>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/87/three.min.js"></script>
    <script async src="https://unpkg.com/es-module-shims@1.3.6/dist/es-module-shims.js"></script>
    <script type="module">
    import * as THREE from 'three';
import {OrbitControls} from 'three/addons/controls/OrbitControls.js';

function main() {
  const canvas = document.querySelector('#c');
  const renderer = new THREE.WebGLRenderer({canvas});

  const cellSize = 256;

  const fov = 75;
  const aspect = 2;  // the canvas default
  const near = 0.1;
  const far = 1000;
  const camera = new THREE.PerspectiveCamera(fov, aspect, near, far);
  camera.position.set(-cellSize * .3, cellSize * .8, -cellSize * .3);

  const controls = new OrbitControls(camera, canvas);
  controls.target.set(cellSize / 2, cellSize / 3, cellSize / 2);
  controls.update();

  const scene = new THREE.Scene();
  scene.background = new THREE.Color('lightblue');

  {
    const color = 0xFFFFFF;
    const intensity = 1;
    const light = new THREE.DirectionalLight(color, intensity);
    light.position.set(-1, 2, 4);
    scene.add(light);
  }

  const cell = new Uint8Array(cellSize * cellSize * cellSize);
  for (let y = 0; y < cellSize; ++y) {
    for (let z = 0; z < cellSize; ++z) {
      for (let x = 0; x < cellSize; ++x) {
        const height = (Math.sin(x / cellSize * Math.PI * 4) + Math.sin(z / cellSize * Math.PI * 6)) * 20 + cellSize / 2;
        if (height > y && height < y + 1) {
          const offset = y * cellSize * cellSize +
                       z * cellSize +
                       x;
          cell[offset] = 1;
        }
      }
    }
  }

  const geometry = new THREE.BoxGeometry(1, 1, 1);
  const material = new THREE.MeshPhongMaterial({color: 'green'});

  for (let y = 0; y < cellSize; ++y) {
    for (let z = 0; z < cellSize; ++z) {
      for (let x = 0; x < cellSize; ++x) {
        const offset = y * cellSize * cellSize +
                       z * cellSize +
                       x;
        const block = cell[offset];
        if (block) {
          const mesh = new THREE.Mesh(geometry, material);
          mesh.position.set(x, y, z);
          scene.add(mesh);
        }
      }
    }
  }

  function resizeRendererToDisplaySize(renderer) {
    const canvas = renderer.domElement;
    const width = canvas.clientWidth;
    const height = canvas.clientHeight;
    const needResize = canvas.width !== width || canvas.height !== height;
    if (needResize) {
      renderer.setSize(width, height, false);
    }
    return needResize;
  }

  let renderRequested = false;

  function render() {
    renderRequested = undefined;

    if (resizeRendererToDisplaySize(renderer)) {
      const canvas = renderer.domElement;
      camera.aspect = canvas.clientWidth / canvas.clientHeight;
      camera.updateProjectionMatrix();
    }

    controls.update();
    renderer.render(scene, camera);
  }
  render();

  function requestRenderIfNotRequested() {
    if (!renderRequested) {
      renderRequested = true;
      requestAnimationFrame(render);
    }
  }

  controls.addEventListener('change', requestRenderIfNotRequested);
  window.addEventListener('resize', requestRenderIfNotRequested);
}

main();
    </script>
  </body>
</html>

this is my code, and for some reason it still doesn’t work. i added the module thing, and put it inside a body tag.

4

you can test it out here, which doesnt work

5

On the page you mentioned, I see this piece is missing, which is present in your original post:

<script  type="importmap">{
  "imports": {
    "three": "https://threejs.org/build/three.module.js",
    "three/addons/": "https://threejs.org/examples/jsm/"
  }
}</script><!-- Remove this when import maps will be widely supported -->
<script async src="https://unpkg.com/es-module-shims@1.3.6/dist/es-module-shims.js"></script>

instead I see this

<script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/87/three.min.js"></script>

if you want to use import map and
import * as THREE from 'three';
then you need to include the map into your page

or don’t use the map but then all imports should mention absolute/relative paths (library “addons” like OrbitControls will not work in this case because they were redesigned to use import maps).

1 Like
6

Thank you!