three.js testbed

with orbitControls, XZgrid, info

by omgazero

HTML

<div id="info">hw2 helper
</div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/84/three.min.js"></script>
<script src="https://threejs.org/examples/js/controls/OrbitControls.js">


</script>
<script src="https://jyunming-chen.github.io/tutsplus/js/KeyboardState.js"></script>

CSS

#info {
  position: absolute;
  top: 0px;
  width: 100%;
  padding: 10px;
  text-align: center;
  color: #ffff00
}

body {
  overflow: hidden;
}

JavaScript

class Ball {
	constructor (mesh, rad = 2, color) {
  
  	this.pos = new THREE.Vector3()
    this.vel = new THREE.Vector3()
    this.force = new THREE.Vector3()
    this.mesh = mesh;
    this.radius = rad;
    this.light = new THREE.PointLight (color, 1, 50);
    scene.add (this.light)
    scene.add (this.mesh)   // add to scene when particle is created

console.log (color)
		this.mesh.material.color.copy ( color.clone() );
  }
  update (dt) {
		this.vel.add (this.force.clone().multiplyScalar (dt))
  	this.pos.add (this.vel.clone().multiplyScalar(dt))
    
		this.collidingPlanes (planes)
    
    // simple collision
  /*
  if (this.pos.z > 100 - this.radius) {
    	const CR = 0.9
    	this.pos.z = 100 - this.radius
      this.vel.z = - CR * this.vel.z;
    }
  */  
		this.mesh.position.copy (this.pos)
    this.light.position.copy (this.pos)
    this.light.position.y += 20
  }

	collidingPlanes (planes) {
    const EPS = 1e-3
    const CR = 0.96
  	for (let i = 0; i < planes.length; i++) {
			let plane = planes[i]
			let point = this.pos.clone().sub (plane.ptOnPl)
      if ( point.dot(plane.normal) < EPS + this.radius) {
				// position correction
      	this.pos.copy (plane.ptOnPl.clone().add (point.projectOnPlane(plane.normal)) )
        this.pos.add (plane.normal.clone().multiplyScalar(this.radius))
      	// velocity update
      	this.vel.sub (plane.normal.clone().multiplyScalar ((1+CR)*this.vel.dot(plane.normal)))
      	//return;  // assume particle collides with AT MOST one plane
      }
  	}
  }

}

class Plane {
	constructor (localPointOnPlane, localNormal, mesh) {
    this.localPtOnPl = localPointOnPlane.clone();
		this.localNormal = localNormal.clone();
    this.mesh = mesh;  // the graphics representation
    scene.add (mesh)
  }
  update () {
  	this.mesh.updateMatrixWorld() // important!
  	this.ptOnPl = this.mesh.localToWorld (this.localPtOnPl.clone());
    let normalMat = new THREE.Matrix3().getNormalMatrix (this.mesh.matrixWorld);  
   ...