public static int mouseAxisHash(int mouseAxis, boolean negative){
        assert mouseAxis >= 0 && mouseAxis <= 255;
        return (negative ? 768 : 512) | (mouseAxis & 0xff);
    }
Create a new <code>MouseAxisTrigger</code>.
<p>
@param mouseAxis Mouse axis. See AXIS_*** constants in {@link MouseInput}
@param negative True if listen to negative axis events, false if
listen to positive axis events.
jme3-core/src/main/java/com/jme3/input/controls/MouseAxisTrigger.java