# Slick and Timers?

I'm making a game where I need events to happen in a precise amount of time. Explanation : I want that event A happens at 12000ms, and event B happens every 10000ms.

So "if"s should looks like this.

//event A
if(Ticks == 12000) //do things
//even B
if(Ticks % 10000 == 0) //do stuff


But now how can I have this "Ticks" value ? I tried to declare an int and then increasing it in the update method, I tried 2 ways of increasing it :

Ticks++;


It doesn't works because the update method is not always called every microseconds.

Ticks += delta;


It's kinda good but the delta is not always equals to 1, so I can miss the precise values I need in the if statements

So if you know how can I do events in a precise amount of time please tell me how can I do this

• stackoverflow.com/questions/1770010/… maybe this can help – Heckel May 26 '14 at 19:52
• I saw that I should use something like ticks = System.nanoTime() but when I start the game and I look at the value its already a very big value – user3491043 May 26 '14 at 20:19

It's a simple change to logic really, simply use a >= test instead. If Ticks is greater than or equal to your trigger amount, you should fire the trigger. Then you use the Ticks += delta; to increment it. Additionally, you can create a more generic object to hold information for a single event.

class EventObject {
float TimeSinceTrigger = 0;
float TriggerInterval;
boolean FireOnce;
boolean Fired;

public EventObject(float triggerInterval, boolean fireOnce) {
TriggerInterval = triggerInterval;
FireOnce = fireOnce;
}

public void update(float delta) {
TimeSinceTrigger += delta;
}

if(FireOnce && Fired)
return false;

if(TimeSinceTrigger >= TriggerInterval) {
//We're ready, if we fire only once, set our flag for that
// otherwise, reset our time since trigger to fire again later.

if(FireOnce)
Fired = true;
else
TimeSinceTrigger = 0;

return true;
}
return false;
}

}


Then you can use that object like:

//Instantiate the objects
EventObject repeatingEvent = new EventObject(1000, false);
EventObject singleFireEvent = new EventObject(1000, true);

//At the beginning of your update loop:
repeatingEvent.update(delta);
singleFireEvent.update(delta);

//Wherever else in your update loop

RunRepeatingEventCode();
}

FireSingleEventCode();
}


With that, you're on your way to a robust event system. It could certainly use a lot of improvement. For example, keeping the event objects in a list, so you can stop updating them if they're done.

As for getting accurate delta time, you're on the right path. You System.nanoTime() would be used like:

long lastUpdate = System.nanoTime();

//In the update method

long currentTime = System.nanoTime();
long delta = currentTime - lastUpdate;
lastUpdate = currentTime;