cannon/src/constraints/Constraint.js

A lightweight 3D physics engine written in JavaScript.

module.exports = Constraint;

var Utils = require('../utils/Utils');

/**
 * Constraint base class
 * @class Constraint
 * @author schteppe
 * @constructor
 * @param {Body} bodyA
 * @param {Body} bodyB
 * @param {object} [options]
 * @param {boolean} [options.collideConnected=true]
 * @param {boolean} [options.wakeUpBodies=true]
 */
function Constraint(bodyA, bodyB, options){
    options = Utils.defaults(options,{
        collideConnected : true,
        wakeUpBodies : true,
    });

    /**
     * Equations to be solved in this constraint
     * @property equations
     * @type {Array}
     */
    this.equations = [];

    /**
     * @property {Body} bodyA
     */
    this.bodyA = bodyA;

    /**
     * @property {Body} bodyB
     */
    this.bodyB = bodyB;

    /**
     * @property {Number} id
     */
    this.id = Constraint.idCounter++;

    /**
     * Set to true if you want the bodies to collide when they are connected.
     * @property collideConnected
     * @type {boolean}
     */
    this.collideConnected = options.collideConnected;

    if(options.wakeUpBodies){
        if(bodyA){
            bodyA.wakeUp();
        }
        if(bodyB){
            bodyB.wakeUp();
        }
    }
}

/**
 * Update all the equations with data.
 * @method update
 */
Constraint.prototype.update = function(){
    throw new Error("method update() not implmemented in this Constraint subclass!");
};

/**
 * Enables all equations in the constraint.
 * @method enable
 */
Constraint.prototype.enable = function(){
    var eqs = this.equations;
    for(var i=0; i<eqs.length; i++){
        eqs[i].enabled = true;
    }
};

/**
 * Disables all equations in the constraint.
 * @method disable
 */
Constraint.prototype.disable = function(){
    var eqs = this.equations;
    for(var i=0; i<eqs.length; i++){
        eqs[i].enabled = false;
    }
};

Constraint.idCounter = 0;