javascript
/
three.js
mirror of https://github.com/tazdij/three.js.git


			
				
					
						
						
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							<body>
  <canvas id="c"></canvas>
</body>
<script type="module">
import * as THREE from '../../build/three.module.js';
import {OrbitControls} from '../../examples/jsm/controls/OrbitControls.js';

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

  const fov = 45;
  const aspect = 2;  // the canvas default
  const near = 0.1;
  const far = 10000;
  const camera = new THREE.PerspectiveCamera(fov, aspect, near, far);
  camera.position.set(0, 1000, 2000);

  const controls = new OrbitControls(camera, canvas);
  controls.target.set(0, 5, 0);
  controls.update();

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

  scene.add(new THREE.GridHelper(5000, 10));

  let curve;
  let curveObject;
  {
    const controlPoints = [
      [1.118281, 5.115846, -3.681386],
      [3.948875, 5.115846, -3.641834],
      [3.960072, 5.115846, -0.240352],
      [3.985447, 5.115846, 4.585005],
      [-3.793631, 5.115846, 4.585006],
      [-3.826839, 5.115846, -14.736200],
      [-14.542292, 5.115846, -14.765865],
      [-14.520929, 5.115846, -3.627002],
      [-5.452815, 5.115846, -3.634418],
      [-5.467251, 5.115846, 4.549161],
      [-13.266233, 5.115846, 4.567083],
      [-13.250067, 5.115846, -13.499271],
      [4.081842, 5.115846, -13.435463],
      [4.125436, 5.115846, -5.334928],
      [-14.521364, 5.115846, -5.239871],
      [-14.510466, 5.115846, 5.486727],
      [5.745666, 5.115846, 5.510492],
      [5.787942, 5.115846, -14.728308],
      [-5.423720, 5.115846, -14.761919],
      [-5.373599, 5.115846, -3.704133],
      [1.004861, 5.115846, -3.641834],
    ];
    const p0 = new THREE.Vector3();
    const p1 = new THREE.Vector3();
    curve = new THREE.CatmullRomCurve3(
      controlPoints.map((p, ndx) => {
        p0.set(...p);
        p1.set(...controlPoints[(ndx + 1) % controlPoints.length]);
        return [
          (new THREE.Vector3()).copy(p0),
          (new THREE.Vector3()).lerpVectors(p0, p1, 0.1),
          (new THREE.Vector3()).lerpVectors(p0, p1, 0.9),
        ];
      }).flat(),
      true,
    );
    {
      const points = curve.getPoints(250);
      const geometry = new THREE.BufferGeometry().setFromPoints(points);
      const material = new THREE.LineBasicMaterial({color: 0xff0000});
      curveObject = new THREE.Line(geometry, material);
      curveObject.scale.set(100, 100, 100);
      curveObject.position.y = -621;
      material.depthTest = false;
      curveObject.renderOrder = 1;
      scene.add(curveObject);
    }
  }

  const geometry = new THREE.BoxGeometry(100, 100, 300);
  const material = new THREE.MeshBasicMaterial({color: 'cyan'});
  const cars = [];
  for (let i = 0; i < 10; ++i) {
    const mesh = new THREE.Mesh(geometry, material);
    scene.add(mesh);
    cars.push(mesh);
  }

  // create 2 Vector3s we can use for path calculations
  const carPosition = new THREE.Vector3();
  const carTarget = new THREE.Vector3();

  function render(time) {
    time *= 0.001;  // convert to seconds

    {
      const pathTime = time * .01;
      const targetOffset = 0.01;
      cars.forEach((car, ndx) => {
        // a number between 0 and 1 to evenly space the cars
        const u = pathTime + ndx / cars.length;

        // get the first point
        curve.getPointAt(u % 1, carPosition);
        carPosition.applyMatrix4(curveObject.matrixWorld);

        // get a second point slightly further down the curve
        curve.getPointAt((u + targetOffset) % 1, carTarget);
        carTarget.applyMatrix4(curveObject.matrixWorld);

        // put the car at the first point (temporarily)
        car.position.copy(carPosition);
        // point the car the second point
        car.lookAt(carTarget);

        // put the car between the 2 points
        car.position.lerpVectors(carPosition, carTarget, 0.5);
      });
    }

    renderer.render(scene, camera);

    requestAnimationFrame(render);
  }

  requestAnimationFrame(render);
}

main();
</script>