Comments for Entropy Interactive

Comment on Game Engine Design – The Game Loop by How can I tell OpenGL how often to draw stuff? - Programmers Goodies

How can I tell OpenGL how often to draw stuff? - Programmers Goodies — Thu, 18 Aug 2011 20:17:52 +0000

[...] http://entropyinteractive.com/2011/02/game-engine-design-the-game-loop/ is a good resource to get you started. [...]

Comment on Game Engine Design – A Simple Game by Jeff

Jeff — Sun, 03 Apr 2011 20:33:39 +0000

Ya I totally understand about being busy with life. To be honest, the main things that I’m looking for out of this tutorial series is a finished Asteroids-type game b/c I am going to use this engine as the basis for a game that would be similar to the Call of Duty Dead Ops arcade game. So, in addition to the things you are already planning on going over, it would be cool to see a tutorial about implementing powerups into the game. Thanks again for writing these and I’ll definitely keep checking back for more tutorials.

Comment on Game Engine Design – A Simple Game by Eric

Eric — Sun, 03 Apr 2011 14:27:09 +0000

Thanks. Unfortunately, my life is kind of busy right now. I will have a lot more free time in a month, and I intend to devote quite a bit of that to this site. If you have any topics that you are interested in, let me know and I’ll try and right a tutorial for it.

Comment on Game Engine Design – A Simple Game by Jeff

Jeff — Sun, 03 Apr 2011 06:50:44 +0000

Hey thanks a lot for making these tutorials! I really appreciate the hard work you have put into them and look forward to seeing more of them in the future!

- Jeff

Comment on Game Engine Design – Logging by Eric

Eric — Thu, 17 Mar 2011 03:29:04 +0000

Yes. The Java logging classes are a bit of overkill for most applications. Also, the tutorials are meant to be as general as possible so I try and stay away from things that are too Java specific.

Comment on Game Engine Design – Logging by Bobby

Bobby — Thu, 17 Mar 2011 03:22:06 +0000

Is there any reason to roll your own vs. using java.util.logging? Seems like the latter would be better; you won’t be re-inventing the wheel, and would keep your payload smaller (important for applets, for example).

Comment on Game Engine Design – The Game Loop by Eric

Eric — Thu, 17 Feb 2011 04:41:08 +0000

I did some more research. Delta time game loops are more common than a had previously thought. I rewrote the game loop to allow for either delta time of fixed time game loops. I don’t think I will modify this tutorial, but I will post a new one soon with the expanded game loop. Thanks for the feedback.

Comment on Game Engine Design – The Game Loop by Beernutts

Beernutts — Fri, 11 Feb 2011 16:49:44 +0000

FWIW, my game uses variable step sizes, and I also have a replay system that just records position of sprites on the screen every 30 ms (or is it 60? I forget) and replays it that way.

I had trouble if I used a fixed time for some really slow machines, so I just use variable time.

Comment on Game Engine Design – The Game Loop by Eric

Eric — Fri, 11 Feb 2011 15:45:52 +0000

I do mention that as an option, but I am not a huge fan of it. One issue that can come up is that the game is not consistent on different systems. The place where this is most obvious is physics. Most physics engines will break down if the step size is to big, and less commonly, to small. Also, is you want any sort of replay system, variable step sizes would be a nightmare.

It is completely possible to make a game loop like that. You just need to be aware of the issues. I feel it is simpler (particularly for beginners) to have every game loop step the same amount of time.

Comment on Game Engine Design – The Game Loop by Beernutts

Beernutts — Fri, 11 Feb 2011 15:34:40 +0000

I don’t think the method you describing is the best way at all. You SHOULD be drawing every frame, but where the objects are you draw should be dependent on the time between frames. So, moving objects need to have a velocity associated with them based on pixels/second (or a similar speed). That way, on slow computers, the objects will be updated less often, but they will have moved the same distance as fast computers, which update more often.

For example, you’re game loop should be:
while(bPlaying)
{
// DeltaTimeInMs is the time since the last frame was drawn, in milliseconds
DeltaTimeInMs = GetDeltaTimeInMs();

// pass the time since the last update, and have the objects that are moving be updated based on how long it’s been since the last update.
bPlaying = update(DeltaTimeInMs();

draw();
}