As you might expect, we will update the HUD variables in the update section of our code. We will not, however, do so every frame. The reason for this is that it is unnecessary and it also slows our game loop down.

As an example, consider the scenario where the player kills a zombie and gets some more points. It doesn't matter whether the Text object that holds the score is updated in a thousandth, hundredth, or even tenth of a second. The player will discern no difference. This means there is no point rebuilding strings that we set to the Text objects every frame.

So we can time when and how often we update the HUD, add the following variables:

// When did we last update the HUD?
int framesSinceLastHUDUpdate = 0;

// How often (in frames) should we update the HUD
int fpsMeasurementFrameInterval = 1000; 
 
// The main game loop 
while (window.isOpen()) 

In the previous code, we have variables to track how many frames it has...