| 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 Elastic extends TweenEquation { |
| private static final float PI = 3.14159265f; |
| |
| public static final Elastic IN = new Elastic() { |
| @Override |
| public final float compute(float t) { |
| float a = param_a; |
| float p = param_p; |
| if (t==0) return 0; if (t==1) return 1; if (!setP) p=.3f; |
| float s; |
| if (!setA || a < 1) { a=1; s=p/4; } |
| else s = p/(2*PI) * (float)Math.asin(1/a); |
| return -(a*(float)Math.pow(2,10*(t-=1)) * (float)Math.sin( (t-s)*(2*PI)/p )); |
| } |
| |
| @Override |
| public String toString() { |
| return "Elastic.IN"; |
| } |
| }; |
| |
| public static final Elastic OUT = new Elastic() { |
| @Override |
| public final float compute(float t) { |
| float a = param_a; |
| float p = param_p; |
| if (t==0) return 0; if (t==1) return 1; if (!setP) p=.3f; |
| float s; |
| if (!setA || a < 1) { a=1; s=p/4; } |
| else s = p/(2*PI) * (float)Math.asin(1/a); |
| return a*(float)Math.pow(2,-10*t) * (float)Math.sin( (t-s)*(2*PI)/p ) + 1; |
| } |
| |
| @Override |
| public String toString() { |
| return "Elastic.OUT"; |
| } |
| }; |
| |
| public static final Elastic INOUT = new Elastic() { |
| @Override |
| public final float compute(float t) { |
| float a = param_a; |
| float p = param_p; |
| if (t==0) return 0; if ((t*=2)==2) return 1; if (!setP) p=.3f*1.5f; |
| float s; |
| if (!setA || a < 1) { a=1; s=p/4; } |
| else s = p/(2*PI) * (float)Math.asin(1/a); |
| if (t < 1) return -.5f*(a*(float)Math.pow(2,10*(t-=1)) * (float)Math.sin( (t-s)*(2*PI)/p )); |
| return a*(float)Math.pow(2,-10*(t-=1)) * (float)Math.sin( (t-s)*(2*PI)/p )*.5f + 1; |
| } |
| |
| @Override |
| public String toString() { |
| return "Elastic.INOUT"; |
| } |
| }; |
| |
| // ------------------------------------------------------------------------- |
| |
| protected float param_a; |
| protected float param_p; |
| protected boolean setA = false; |
| protected boolean setP = false; |
| |
| public Elastic a(float a) { |
| param_a = a; |
| this.setA = true; |
| return this; |
| } |
| |
| public Elastic p(float p) { |
| param_p = p; |
| this.setP = true; |
| return this; |
| } |
| } |