API Docs for: 0.6.1
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File: src/objects/WheelInfo.js

var Vec3 = require('../math/Vec3');
var Transform = require('../math/Transform');
var RaycastResult = require('../collision/RaycastResult');
var Utils = require('../utils/Utils');

module.exports = WheelInfo;

/**
 * @class WheelInfo
 * @constructor
 * @param {Object} [options]
 *
 * @param {Vec3} [options.chassisConnectionPointLocal]
 * @param {Vec3} [options.chassisConnectionPointWorld]
 * @param {Vec3} [options.directionLocal]
 * @param {Vec3} [options.directionWorld]
 * @param {Vec3} [options.axleLocal]
 * @param {Vec3} [options.axleWorld]
 * @param {number} [options.suspensionRestLength=1]
 * @param {number} [options.suspensionMaxLength=2]
 * @param {number} [options.radius=1]
 * @param {number} [options.suspensionStiffness=100]
 * @param {number} [options.dampingCompression=10]
 * @param {number} [options.dampingRelaxation=10]
 * @param {number} [options.frictionSlip=10000]
 * @param {number} [options.steering=0]
 * @param {number} [options.rotation=0]
 * @param {number} [options.deltaRotation=0]
 * @param {number} [options.rollInfluence=0.01]
 * @param {number} [options.maxSuspensionForce]
 * @param {boolean} [options.isFrontWheel=true]
 * @param {number} [options.clippedInvContactDotSuspension=1]
 * @param {number} [options.suspensionRelativeVelocity=0]
 * @param {number} [options.suspensionForce=0]
 * @param {number} [options.skidInfo=0]
 * @param {number} [options.suspensionLength=0]
 * @param {number} [options.maxSuspensionTravel=1]
 * @param {boolean} [options.useCustomSlidingRotationalSpeed=false]
 * @param {number} [options.customSlidingRotationalSpeed=-0.1]
 */
function WheelInfo(options){
    options = Utils.defaults(options, {
        chassisConnectionPointLocal: new Vec3(),
        chassisConnectionPointWorld: new Vec3(),
        directionLocal: new Vec3(),
        directionWorld: new Vec3(),
        axleLocal: new Vec3(),
        axleWorld: new Vec3(),
        suspensionRestLength: 1,
        suspensionMaxLength: 2,
        radius: 1,
        suspensionStiffness: 100,
        dampingCompression: 10,
        dampingRelaxation: 10,
        frictionSlip: 10000,
        steering: 0,
        rotation: 0,
        deltaRotation: 0,
        rollInfluence: 0.01,
        maxSuspensionForce: Number.MAX_VALUE,
        isFrontWheel: true,
        clippedInvContactDotSuspension: 1,
        suspensionRelativeVelocity: 0,
        suspensionForce: 0,
        skidInfo: 0,
        suspensionLength: 0,
        maxSuspensionTravel: 1,
        useCustomSlidingRotationalSpeed: false,
        customSlidingRotationalSpeed: -0.1
    });

    /**
     * Max travel distance of the suspension, in meters.
     * @property {number} maxSuspensionTravel
     */
    this.maxSuspensionTravel = options.maxSuspensionTravel;

    /**
     * Speed to apply to the wheel rotation when the wheel is sliding.
     * @property {number} customSlidingRotationalSpeed
     */
    this.customSlidingRotationalSpeed = options.customSlidingRotationalSpeed;

    /**
     * If the customSlidingRotationalSpeed should be used.
     * @property {Boolean} useCustomSlidingRotationalSpeed
     */
    this.useCustomSlidingRotationalSpeed = options.useCustomSlidingRotationalSpeed;

    /**
     * @property {Boolean} sliding
     */
    this.sliding = false;

    /**
     * Connection point, defined locally in the chassis body frame.
     * @property {Vec3} chassisConnectionPointLocal
     */
    this.chassisConnectionPointLocal = options.chassisConnectionPointLocal.clone();

    /**
     * @property {Vec3} chassisConnectionPointWorld
     */
    this.chassisConnectionPointWorld = options.chassisConnectionPointWorld.clone();

    /**
     * @property {Vec3} directionLocal
     */
    this.directionLocal = options.directionLocal.clone();

    /**
     * @property {Vec3} directionWorld
     */
    this.directionWorld = options.directionWorld.clone();

    /**
     * @property {Vec3} axleLocal
     */
    this.axleLocal = options.axleLocal.clone();

    /**
     * @property {Vec3} axleWorld
     */
    this.axleWorld = options.axleWorld.clone();

    /**
     * @property {number} suspensionRestLength
     */
    this.suspensionRestLength = options.suspensionRestLength;

    /**
     * @property {number} suspensionMaxLength
     */
    this.suspensionMaxLength = options.suspensionMaxLength;

    /**
     * @property {number} radius
     */
    this.radius = options.radius;

    /**
     * @property {number} suspensionStiffness
     */
    this.suspensionStiffness = options.suspensionStiffness;

    /**
     * @property {number} dampingCompression
     */
    this.dampingCompression = options.dampingCompression;

    /**
     * @property {number} dampingRelaxation
     */
    this.dampingRelaxation = options.dampingRelaxation;

    /**
     * @property {number} frictionSlip
     */
    this.frictionSlip = options.frictionSlip;

    /**
     * @property {number} steering
     */
    this.steering = 0;

    /**
     * Rotation value, in radians.
     * @property {number} rotation
     */
    this.rotation = 0;

    /**
     * @property {number} deltaRotation
     */
    this.deltaRotation = 0;

    /**
     * @property {number} rollInfluence
     */
    this.rollInfluence = options.rollInfluence;

    /**
     * @property {number} maxSuspensionForce
     */
    this.maxSuspensionForce = options.maxSuspensionForce;

    /**
     * @property {number} engineForce
     */
    this.engineForce = 0;

    /**
     * @property {number} brake
     */
    this.brake = 0;

    /**
     * @property {number} isFrontWheel
     */
    this.isFrontWheel = options.isFrontWheel;

    /**
     * @property {number} clippedInvContactDotSuspension
     */
    this.clippedInvContactDotSuspension = 1;

    /**
     * @property {number} suspensionRelativeVelocity
     */
    this.suspensionRelativeVelocity = 0;

    /**
     * @property {number} suspensionForce
     */
    this.suspensionForce = 0;

    /**
     * @property {number} skidInfo
     */
    this.skidInfo = 0;

    /**
     * @property {number} suspensionLength
     */
    this.suspensionLength = 0;

    /**
     * @property {number} sideImpulse
     */
    this.sideImpulse = 0;

    /**
     * @property {number} forwardImpulse
     */
    this.forwardImpulse = 0;

    /**
     * The result from raycasting
     * @property {RaycastResult} raycastResult
     */
    this.raycastResult = new RaycastResult();

    /**
     * Wheel world transform
     * @property {Transform} worldTransform
     */
    this.worldTransform = new Transform();

    /**
     * @property {boolean} isInContact
     */
    this.isInContact = false;
}

var chassis_velocity_at_contactPoint = new Vec3();
var relpos = new Vec3();
var chassis_velocity_at_contactPoint = new Vec3();
WheelInfo.prototype.updateWheel = function(chassis){
    var raycastResult = this.raycastResult;

    if (this.isInContact){
        var project= raycastResult.hitNormalWorld.dot(raycastResult.directionWorld);
        raycastResult.hitPointWorld.vsub(chassis.position, relpos);
        chassis.getVelocityAtWorldPoint(relpos, chassis_velocity_at_contactPoint);
        var projVel = raycastResult.hitNormalWorld.dot( chassis_velocity_at_contactPoint );
        if (project >= -0.1) {
            this.suspensionRelativeVelocity = 0.0;
            this.clippedInvContactDotSuspension = 1.0 / 0.1;
        } else {
            var inv = -1 / project;
            this.suspensionRelativeVelocity = projVel * inv;
            this.clippedInvContactDotSuspension = inv;
        }

    } else {
        // Not in contact : position wheel in a nice (rest length) position
        raycastResult.suspensionLength = this.suspensionRestLength;
        this.suspensionRelativeVelocity = 0.0;
        raycastResult.directionWorld.scale(-1, raycastResult.hitNormalWorld);
        this.clippedInvContactDotSuspension = 1.0;
    }
};