Method flicker

packages/melonjs/src/renderable/sprite.js:475–487

* make the object flicker * @param {number} duration - expressed in milliseconds * @param {Function} [callback] - Function to call when flickering ends * @returns {Sprite} Reference to this object for method chaining * @example * // make the object flicker for 1 second * // and then remo

(duration, callback = undefined)

	 * });
	 */
	flicker(duration, callback = undefined) {
		this._flicker.duration = duration;
		if (this._flicker.duration <= 0) {
			this._flicker.isFlickering = false;
			this._flicker.callback = undefined;
			this._flicker.elapsed = 0;
		} else {
			this._flicker.callback = callback;
			this._flicker.elapsed = 0;
			this._flicker.isFlickering = true;
		}
		return this;
	}

	/**
	 * add an animation <br>