cannon/src/constraints/LockConstraint.js

A lightweight 3D physics engine written in JavaScript.

module.exports = LockConstraint;

var Constraint = require('./Constraint');
var PointToPointConstraint = require('./PointToPointConstraint');
var RotationalEquation = require('../equations/RotationalEquation');
var RotationalMotorEquation = require('../equations/RotationalMotorEquation');
var ContactEquation = require('../equations/ContactEquation');
var Vec3 = require('../math/Vec3');

/**
 * Lock constraint. Will remove all degrees of freedom between the bodies.
 * @class LockConstraint
 * @constructor
 * @author schteppe
 * @param {Body} bodyA
 * @param {Body} bodyB
 * @param {object} [options]
 * @param {Number} [options.maxForce=1e6]
 * @extends PointToPointConstraint
 */
function LockConstraint(bodyA, bodyB, options){
    options = options || {};
    var maxForce = typeof(options.maxForce) !== 'undefined' ? options.maxForce : 1e6;

    // Set pivot point in between
    var pivotA = new Vec3();
    var pivotB = new Vec3();
    var halfWay = new Vec3();
    bodyA.position.vadd(bodyB.position, halfWay);
    halfWay.scale(0.5, halfWay);
    bodyB.pointToLocalFrame(halfWay, pivotB);
    bodyA.pointToLocalFrame(halfWay, pivotA);
    PointToPointConstraint.call(this, bodyA, pivotA, bodyB, pivotB, maxForce);

    /**
     * @property {RotationalEquation} rotationalEquation1
     */
    var r1 = this.rotationalEquation1 = new RotationalEquation(bodyA,bodyB,options);

    /**
     * @property {RotationalEquation} rotationalEquation2
     */
    var r2 = this.rotationalEquation2 = new RotationalEquation(bodyA,bodyB,options);

    /**
     * @property {RotationalEquation} rotationalEquation3
     */
    var r3 = this.rotationalEquation3 = new RotationalEquation(bodyA,bodyB,options);

    this.equations.push(r1, r2, r3);
}
LockConstraint.prototype = new PointToPointConstraint();
LockConstraint.constructor = LockConstraint;

var LockConstraint_update_tmpVec1 = new Vec3();
var LockConstraint_update_tmpVec2 = new Vec3();

LockConstraint.prototype.update = function(){
    var bodyA = this.bodyA,
        bodyB = this.bodyB,
        motor = this.motorEquation,
        r1 = this.rotationalEquation1,
        r2 = this.rotationalEquation2,
        r3 = this.rotationalEquation3,
        worldAxisA = LockConstraint_update_tmpVec1,
        worldAxisB = LockConstraint_update_tmpVec2;

    PointToPointConstraint.prototype.update.call(this);

    bodyA.vectorToWorldFrame(Vec3.UNIT_X, r1.axisA);
    bodyB.vectorToWorldFrame(Vec3.UNIT_Y, r1.axisB);

    bodyA.vectorToWorldFrame(Vec3.UNIT_Y, r2.axisA);
    bodyB.vectorToWorldFrame(Vec3.UNIT_Z, r2.axisB);

    bodyA.vectorToWorldFrame(Vec3.UNIT_Z, r3.axisA);
    bodyB.vectorToWorldFrame(Vec3.UNIT_X, r3.axisB);
};