Method addKeyboardHandler

src/main/java/field/graphics/Window.java:680–683

A keyboard handler is a Function , Boolean>>, that is a function that takes a transition between two KeyboardStates and returns a boolean, whether or not it ever wants to be called again

(Function<Event<KeyboardState>, Boolean> h)

     */
    @HiddenInAutocomplete
    public void fireMouseTransition(MouseState before, MouseState after) {
        after.keyboardState = keyboardState;

        if ((after.mods & GLFW_MOD_SHIFT) != 0)
            after.keyboardState = after.keyboardState.withKey(GLFW_KEY_LEFT_SHIFT, true);
        else after.keyboardState = after.keyboardState.withKey(GLFW_KEY_LEFT_SHIFT, false)
                .withKey(GLFW_KEY_RIGHT_SHIFT, false);