[fixed] issue 822: simplified statement to calculate interpolated alp…

…ha value

git-svn-id: http://libgdx.googlecode.com/svn/trunk@3905 6c4fd544-2939-11df-bb46-9574ba5d0bfa

gdx/src/com/badlogic/gdx/scenes/scene2d/AnimationAction.java

@@ -61,8 +61,7 @@ protected float createInterpolatedAlpha (float delta) {
 		} else if (interpolator == null) {
 			return taken * invDuration;
 		} else {
-			float interpolatedTime = interpolator.getInterpolation(taken / duration) * duration;
-			return interpolatedTime * invDuration;
+			return interpolator.getInterpolation(taken * invDuration);
 		}
 	}