phaser/Phaser/tweens/Tween.ts

/// <reference path="../_definitions.ts" />

/**
* Phaser - Tween
*
* Based heavily on tween.js by sole (https://github.com/sole/tween.js) converted to TypeScript and integrated into Phaser
*/

module Phaser {

    export class Tween {

        /**
         * Tween constructor
         * Create a new <code>Tween</code>.
         *
         * @param object {object} Target object will be affected by this tween.
         * @param game {Phaser.Game} Current game instance.
         */
        constructor(object, game: Phaser.Game) {

            this._object = object;

            this.game = game;
            this._manager = this.game.tweens;
            this._interpolationFunction = this.game.math.linearInterpolation;
            this._easingFunction = Phaser.Easing.Linear.None;

            this._chainedTweens = [];
            this.onStart = new Phaser.Signal;
            this.onUpdate = new Phaser.Signal;
            this.onComplete = new Phaser.Signal;

        }

        /**
         * Local reference to Game.
         */
        public game: Phaser.Game;

        /**
         * Manager of this tween.
         * @type {Phaser.TweenManager}
         */
        private _manager: Phaser.TweenManager;

        /**
         * Reference to the target object.
         * @type {object}
         */
        private _object = null;

        private _pausedTime: number = 0;

        /**
         * Start values container.
         * @type {object}
         */
        private _valuesStart = {};

        /**
         * End values container.
         * @type {object}
         */
        private _valuesEnd = {};

        /**
         * How long this tween will perform.
         * @type {number}
         */
        private _duration: number = 1000;
        private _delayTime: number = 0;
        private _startTime: number = null;

        //  Temp vars to avoid gc spikes
        private _tempElapsed: number;
        private _tempValue;

        /**
         * Will this tween automatically restart when it completes?
         * @type {bool}
         */
        private _loop: bool = false;

        /**
         * A yoyo tween is one that plays once fully, then reverses back to the original tween values before completing.
         * @type {bool}
         */
        private _yoyo: bool = false;
        private _yoyoCount: number = 0;

        /**
         * Easing function which actually updating this tween.
         * @type {function}
         */
        private _easingFunction;
        private _interpolationFunction;

        /**
         * Contains chained tweens.
         * @type {Tweens[]}
         */
        private _chainedTweens = [];

        /**
         * Signal to be dispatched when this tween start.
         * @type {Phaser.Signal}
         */
        public onStart: Phaser.Signal;

        /**
         * Signal to be dispatched when this tween updating.
         * @type {Phaser.Signal}
         */
        public onUpdate: Phaser.Signal;

        /**
         * Signal to be dispatched when this tween completed.
         * @type {Phaser.Signal}
         */
        public onComplete: Phaser.Signal;

        /**
         * Configure the Tween
         * @param properties {object} Propertis you want to tween.
         * @param [duration] {number} duration of this tween.
         * @param [ease] {any} Easing function.
         * @param [autoStart] {bool} Whether this tween will start automatically or not.
         * @param [delay] {number} delay before this tween will start, defaults to 0 (no delay)
         * @param [loop] {bool} Should the tween automatically restart once complete? (ignores any chained tweens)
         * @return {Tween} Itself.
         */
        public to(properties, duration: number = 1000, ease: any = null, autoStart: bool = false, delay: number = 0, loop: bool = false, yoyo: bool = false): Phaser.Tween {

            this._duration = duration;

            //  If properties isn't an object this will fail, sanity check it here somehow?
            this._valuesEnd = properties;

            if (ease !== null)
            {
                this._easingFunction = ease;
            }

            if (delay > 0)
            {
                this._delayTime = delay;
            }

            this._loop = loop;
            this._yoyo = yoyo;
            this._yoyoCount = 0;

            if (autoStart === true)
            {
                return this.start();
            }
            else
            {
                return this;
            }

        }

        public loop(value: bool): Phaser.Tween {

            this._loop = value;
            return this;

        }

        public yoyo(value: bool): Phaser.Tween {

            this._yoyo = value;
            this._yoyoCount = 0;
            return this;

        }

        public isRunning: bool = false;

        /**
         * Start to tween.
         */
        public start(looped: bool = false): Phaser.Tween {

            if (this.game === null || this._object === null)
            {
                return;
            }

            if (looped == false)
            {
                this._manager.add(this);

                this.onStart.dispatch(this._object);
            }

            this._startTime = this.game.time.now + this._delayTime;
            this.isRunning = true;

            for (var property in this._valuesEnd)
            {
                // This prevents the interpolation of null values or of non-existing properties
                if (this._object[property] === null || !(property in this._object))
                {
                    throw Error('Phaser.Tween interpolation of null value of non-existing property');
                    continue;
                }

                // check if an Array was provided as property value
                if (this._valuesEnd[property] instanceof Array)
                {
                    if (this._valuesEnd[property].length === 0)
                    {
                        continue;
                    }

                    // create a local copy of the Array with the start value at the front
                    this._valuesEnd[property] = [this._object[property]].concat(this._valuesEnd[property]);
                }

                if (looped == false)
                {
                    this._valuesStart[property] = this._object[property];
                }

            }

            return this;

        }

        public reverse() {

            var tempObj = {};

            for (var property in this._valuesStart)
            {
                tempObj[property] = this._valuesStart[property];
                this._valuesStart[property] = this._valuesEnd[property];
                this._valuesEnd[property] = tempObj[property];
            }

            this._yoyoCount++;

            return this.start(true);

        }

        public reset(): Phaser.Tween {

            //  Reset the properties back to what they were before
            for (var property in this._valuesStart)
            {
                this._object[property] = this._valuesStart[property];
            }

            return this.start(true);

        }

        public clear(): Phaser.Tween {

            this._chainedTweens = [];

            this.onStart.removeAll();
            this.onUpdate.removeAll();
            this.onComplete.removeAll();

            return this;

        }

        /**
         * Stop tweening.
         */
        public stop(): Phaser.Tween {

            if (this._manager !== null)
            {
                this._manager.remove(this);
            }

            this.isRunning = false;

            this.onComplete.dispose();

            return this;

        }

        public set parent(value: Phaser.Game) {

            this.game = value;
            this._manager = this.game.tweens;

        }

        public set delay(amount: number) {
            this._delayTime = amount;
        }

        public get delay(): number {
            return this._delayTime;
        }

        public set easing(easing) {
            this._easingFunction = easing;
        }

        public get easing() {
            return this._easingFunction;
        }

        public set interpolation(interpolation) {
            this._interpolationFunction = interpolation;
        }

        public get interpolation() {
            return this._interpolationFunction;
        }

        /**
         * Add another chained tween, which will start automatically when the one before it completes.
         * @param tween {Phaser.Tween} Tween object you want to chain with this.
         * @return {Phaser.Tween} Itselfe.
         */
        public chain(tween: Phaser.Tween): Phaser.Tween {

            this._chainedTweens.push(tween);

            return this;

        }

        public pause() {
            this._paused = true;
        }

        public resume() {

            this._paused = false;
            this._startTime += this.game.time.pauseDuration;

        }

        private _paused: bool;

        /**
         * Update tweening.
         * @param time {number} Current time from game clock.
         * @return {bool} Return false if this completed and no need to update, otherwise return true.
         */
        public update(time: number) {

            if (this._paused || time < this._startTime)
            {
                return true;
            }

            this._tempElapsed = (time - this._startTime) / this._duration;
            this._tempElapsed = this._tempElapsed > 1 ? 1 : this._tempElapsed;

            this._tempValue = this._easingFunction(this._tempElapsed);

            for (var property in this._valuesStart)
            {
                //  Add checks for object, array, numeric up front
                if (this._valuesEnd[property] instanceof Array)
                {
                    this._object[property] = this._interpolationFunction(this._valuesEnd[property], this._tempValue);
                }
                else
                {
                    this._object[property] = this._valuesStart[property] + (this._valuesEnd[property] - this._valuesStart[property]) * this._tempValue;
                }
            }

            this.onUpdate.dispatch(this._object, this._tempValue);

            if (this._tempElapsed == 1)
            {
                //  Yoyo?
                if (this._yoyo)
                {
                    if (this._yoyoCount == 0)
                    {
                        //  Reverse the tween
                        this.reverse();
                        return true;
                    }
                    else
                    {
                        //  We've yoyo'd once already, quit?
                        if (this._loop == false)
                        {
                            this.onComplete.dispatch(this._object);

                            for (var i = 0; i < this._chainedTweens.length; i++)
                            {
                                this._chainedTweens[i].start();
                            }

                            return false;
                        }
                        else
                        {
                            //  YoYo and Loop are both on
                            this._yoyoCount = 0;
                            this.reverse();
                            return true;
                        }
                    }
                }

                //  Loop?
                if (this._loop)
                {
                    this._yoyoCount = 0;
                    this.reset();
                    return true;
                }
                else
                {
                    this.onComplete.dispatch(this._object);

                    for (var i = 0; i < this._chainedTweens.length; i++)
                    {
                        this._chainedTweens[i].start();
                    }

                    if (this._chainedTweens.length == 0)
                    {
                        this.isRunning = false;
                    }

                    return false;
                }

            }

            return true;

        }

    }
}