/wsr/ - Worksafe Requests » Thread #1489709

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Anonymous Mon 16 Sep 2024 23:30:25 No.1489709 View View Reply Original Report

Idiot here. Any help on how to improve this for my game loop? I'm a /noprogrammer/ and trying to do a 2D game learning project. Would appreciate any optimization help :)

Anonymous

Anonymous Tue 17 Sep 2024 02:04:46 No.1489725 Report

Quoted By: >>1489799

I'm going to be handholdy as fuck, but I don't know how much of that was written by you and how much was copypasted so I'll cover my bases.
It's premature to optimise this early, but something you'll want to do is get the time between the current frame and the previous frame and pass it into your update function:
Underneath the
>double nextDrawTime = System.nanoTime() + drawInterval;
add
>double deltaTime = 0;
>double prevFrame = System.nanoTime();
The top variable is going to be the difference in time between the previous frame and the current frame. Right now it's zero just so nothing crazy happens. The prevFrame variable will be used to calculate it further down (it'll be 0 anyway).
Inside the while loop, before update(), add
>prevFrame = System.nanoTime();
and change the update() to
>update(deltaTime);
Remembering to change its definition elsewhere to update(double deltaTime) or something so you can actually make use of the argument in your update loop (some people would shorten it to dt)
Finally, at the very end of your while loop, add
>deltaTime = System.nanoTime() - prevFrame;
Delta time is how to make your game logic framerate-independent. Instead of moving a player by doing something like
>player.x += 150
you would then do
>player.x += 150 * deltaTime
which works out to be 150 per second no matter what instead of 150 per frame, which might happen 6 times per second or 1200 times per second depending on vsync or stuttering.

A pointlessly minor optimisation in your code that I'll point out just so you can learn, is that the line
>remainingTime = remainingTime / 1000000;
should go into an else{} after you check that it's <0, since if it's negative it doesn't matter if it's divide beforehand or not. I'll say again though, in this situation it's a pointless as fuck optimisation, but maybe next time it won't be a single division that could be moved into an else{}

Anonymous

Anonymous Tue 17 Sep 2024 15:31:45 No.1489799 Report

Quoted By:

>>1489725
Hey, thanks for responding.
>but I don't know how much of that was written by you and how much was copypasted so I'll cover my bases
Definitely got my fair share of help from Stackoverflow on the steps to construct a simple game loop. Didn't know where to begin, honestly.
>which works out to be 150 per second no matter what instead of 150 per frame
Ahh, thank you for explaining delta time for me. I did read about that but didn't understand the purpose of it.
So it just smooths out the gameplay so a player entity (for instance) doesn't slow down or speed up depending on framerate?

>should go into an else{} after you check that it's <0
if (remainingTime < 0) {
remainingTime = 0;
} else {
remainingTime = remainingTime / 1000000;
}
Like this, right? Agreed that saving this computation doesn't make or break any modern CPU, but hey, best practises.
Just doing this stuff on my freetime because I want to get better at Java. Only had Python in college mostly for math.

Anonymous

Anonymous Wed 18 Sep 2024 15:34:31 No.1489970 Report

Quoted By:

>>1489709
you will probably have more success posting this on /g/

Anonymous

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Anonymous Thu 19 Sep 2024 07:46:55 No.1490095 Report

Quoted By: >>1490106

i dont think there's any point in having the try/catch block there. all you're doing is arithmetic and pausing the thread-- there's nothing that could possibly fail if you wrote code that works

this code is the same as what you have but with fewer operations and fewer lines

any time you have a variable that you're modifying in a loop (nextDrawTime) and also modifying before the first iteration of the loop, you can usually just rearrange some stuff and you'll have much neater code

Anonymous

Anonymous Thu 19 Sep 2024 09:42:55 No.1490106 Report

Quoted By:

>>1490095
I tried implementing your code without try/catch but unforunately I got the same error that forced me to use it, which was InterruptedException. My IDE had the "surround with try/catch" marker so I used that which fixed it. If you have any ideas why this is, I'd be interested to hear it. Just based on the documentation it says that sleep() throws InterruptedException when another thread interrupts the sleeping thread.

>any time you have a variable that you're modifying in a loop (nextDrawTime) and also modifying before the first iteration of the loop, you can usually just rearrange some stuff and you'll have much neater code
Good point. I've changed it in my code, thanks for the tip :)

Anonymous

Anonymous Fri 20 Sep 2024 21:52:30 No.1490381 Report

Quoted By:

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