@awayjs/core/lib/utils/RequestAnimationFrame.ts

AwayJS core classes

import { getTimer } from './getTimer';

export class RequestAnimationFrame {
	private _callback: Function;
	private _callbackContext: Object;
	private _active: boolean = false;
	private _rafUpdateFunction: any;
	private _prevTime: number;
	private _dt: number;
	private _currentTime: number;
	private _argsArray: Array<any> = new Array();
	private _getTimer: Function;

	constructor(callback: Function, callbackContext: Object) {
		this._getTimer = getTimer;

		this.setCallback(callback, callbackContext);

		this._rafUpdateFunction = () => {
			if (this._active)
				this._tick();
		};

		this._argsArray.push(this._dt);
	}

	// Public

	/**
	 *
	 * @param callback
	 * @param callbackContext
	 */
	public setCallback(callback: Function, callbackContext: Object): void {
		this._callback = callback;
		this._callbackContext = callbackContext;
	}

	/**
	 *
	 */
	public start(): void {
		this._prevTime = this._getTimer();
		this._active = true;

		if (window) {
			if (window.requestAnimationFrame) {
				window.requestAnimationFrame(this._rafUpdateFunction);
			} else {
				if (window['mozRequestAnimationFrame'])
					window.requestAnimationFrame = window['mozRequestAnimationFrame'];
				else if (window['webkitRequestAnimationFrame'])
					window.requestAnimationFrame = window['webkitRequestAnimationFrame'];
				else if (window['oRequestAnimationFrame'])
					window.requestAnimationFrame = window['oRequestAnimationFrame'];
			}
		}
	}

	/**
	 *
	 */
	public stop(): void {
		this._active = false;
	}

	// Get / Set

	/**
	 *
	 * @returns {boolean}
	 */
	public get active(): boolean {
		return this._active;
	}

	// Private

	/**
	 *
	 * @private
	 */
	private _tick(): void {
		this._currentTime = this._getTimer();
		this._dt = this._currentTime - this._prevTime;
		this._argsArray[0] = this._dt;
		this._callback.apply(this._callbackContext, this._argsArray);

		//check to see if callback has stopped RAF
		if (this._active) {
			window.requestAnimationFrame(this._rafUpdateFunction);

			this._prevTime = this._currentTime;
		}
	}

}