cannon/src/math/Transform.js

A lightweight 3D physics engine written in JavaScript.

var Vec3 = require('./Vec3');
var Quaternion = require('./Quaternion');

module.exports = Transform;

/**
 * @class Transform
 * @constructor
 */
function Transform(options) {
    options = options || {};

	/**
	 * @property {Vec3} position
	 */
	this.position = new Vec3();
    if(options.position){
        this.position.copy(options.position);
    }

	/**
	 * @property {Quaternion} quaternion
	 */
	this.quaternion = new Quaternion();
    if(options.quaternion){
        this.quaternion.copy(options.quaternion);
    }
}

var tmpQuat = new Quaternion();

/**
 * @static
 * @method pointToLocaFrame
 * @param {Vec3} position
 * @param {Quaternion} quaternion
 * @param {Vec3} worldPoint
 * @param {Vec3} result
 */
Transform.pointToLocalFrame = function(position, quaternion, worldPoint, result){
    var result = result || new Vec3();
    worldPoint.vsub(position, result);
    quaternion.conjugate(tmpQuat);
    tmpQuat.vmult(result, result);
    return result;
};

/**
 * Get a global point in local transform coordinates.
 * @method pointToLocal
 * @param  {Vec3} point
 * @param  {Vec3} result
 * @return {Vec3} The "result" vector object
 */
Transform.prototype.pointToLocal = function(worldPoint, result){
    return Transform.pointToLocalFrame(this.position, this.quaternion, worldPoint, result);
};

/**
 * @static
 * @method pointToWorldFrame
 * @param {Vec3} position
 * @param {Vec3} quaternion
 * @param {Vec3} localPoint
 * @param {Vec3} result
 */
Transform.pointToWorldFrame = function(position, quaternion, localPoint, result){
    var result = result || new Vec3();
    quaternion.vmult(localPoint, result);
    result.vadd(position, result);
    return result;
};

/**
 * Get a local point in global transform coordinates.
 * @method pointToWorld
 * @param  {Vec3} point
 * @param  {Vec3} result
 * @return {Vec3} The "result" vector object
 */
Transform.prototype.pointToWorld = function(localPoint, result){
    return Transform.pointToWorldFrame(this.position, this.quaternion, localPoint, result);
};


Transform.prototype.vectorToWorldFrame = function(localVector, result){
    var result = result || new Vec3();
    this.quaternion.vmult(localVector, result);
    return result;
};

Transform.vectorToWorldFrame = function(quaternion, localVector, result){
    quaternion.vmult(localVector, result);
    return result;
};

Transform.vectorToLocalFrame = function(position, quaternion, worldVector, result){
    var result = result || new Vec3();
    quaternion.w *= -1;
    quaternion.vmult(worldVector, result);
    quaternion.w *= -1;
    return result;
};