public float getMix(Animation from, Animation to) {
tempKey.a1 = from;
tempKey.a2 = to;
Float time = animationToMixTime.get(tempKey);
if (time == null) return 0;
return time;
}
public void setMix(Animation from, Animation to, float duration) {
if (from == null) throw new IllegalArgumentException("from cannot be null.");
if (to == null) throw new IllegalArgumentException("to cannot be null.");
Key key = new Key();
key.a1 = from;
key.a2 = to;
animationToMixTime.put(key, duration);
}