cannon/src/shapes/Plane.js

A lightweight 3D physics engine written in JavaScript.

module.exports = Plane;

var Shape = require('./Shape');
var Vec3 = require('../math/Vec3');

/**
 * A plane, facing in the Z direction. The plane has its surface at z=0 and everything below z=0 is assumed to be solid plane. To make the plane face in some other direction than z, you must put it inside a RigidBody and rotate that body. See the demos.
 * @class Plane
 * @constructor
 * @extends Shape
 * @author schteppe
 */
function Plane(){
    Shape.call(this);
    this.type = Shape.types.PLANE;

    // World oriented normal
    this.worldNormal = new Vec3();
    this.worldNormalNeedsUpdate = true;

    this.boundingSphereRadius = Number.MAX_VALUE;
}
Plane.prototype = new Shape();
Plane.prototype.constructor = Plane;

Plane.prototype.computeWorldNormal = function(quat){
    var n = this.worldNormal;
    n.set(0,0,1);
    quat.vmult(n,n);
    this.worldNormalNeedsUpdate = false;
};

Plane.prototype.calculateLocalInertia = function(mass,target){
    target = target || new Vec3();
    return target;
};

Plane.prototype.volume = function(){
    return Number.MAX_VALUE; // The plane is infinite...
};

var tempNormal = new Vec3();
Plane.prototype.calculateWorldAABB = function(pos, quat, min, max){
    // The plane AABB is infinite, except if the normal is pointing along any axis
    tempNormal.set(0,0,1); // Default plane normal is z
    quat.vmult(tempNormal,tempNormal);
    var maxVal = Number.MAX_VALUE;
    min.set(-maxVal, -maxVal, -maxVal);
    max.set(maxVal, maxVal, maxVal);

    if(tempNormal.x === 1){ max.x = pos.x; }
    if(tempNormal.y === 1){ max.y = pos.y; }
    if(tempNormal.z === 1){ max.z = pos.z; }

    if(tempNormal.x === -1){ min.x = pos.x; }
    if(tempNormal.y === -1){ min.y = pos.y; }
    if(tempNormal.z === -1){ min.z = pos.z; }
};

Plane.prototype.updateBoundingSphereRadius = function(){
    this.boundingSphereRadius = Number.MAX_VALUE;
};