Quart.java

package aurelienribon.tweenengine.equations;

import aurelienribon.tweenengine.TweenEquation;

/**
 * Easing equation based on Robert Penner's work:
 * http://robertpenner.com/easing/
 * @author Aurelien Ribon | http://www.aurelienribon.com/
 */
public abstract class Quart extends TweenEquation {
	public static final Quart IN = new Quart() {
		@Override
		public final float compute(float t) {
			return t*t*t*t;
		}

		@Override
		public String toString() {
			return "Quart.IN";
		}
	};

	public static final Quart OUT = new Quart() {
		@Override
		public final float compute(float t) {
			return -((t-=1)*t*t*t - 1);
		}

		@Override
		public String toString() {
			return "Quart.OUT";
		}
	};

	public static final Quart INOUT = new Quart() {
		@Override
		public final float compute(float t) {
			if ((t*=2) < 1) return 0.5f*t*t*t*t;
			return -0.5f * ((t-=2)*t*t*t - 2);
		}

		@Override
		public String toString() {
			return "Quart.INOUT";
		}
	};
}