2D physics engine

Guest · Post by **Guest** » Sun Apr 16, 2006 3:12 am

Well, I know that you guys know a lot about game programming because I used to come here a lot, anyways I got more interested in 2D game creation, which is more suitable for a 1 person amateur game designer. Anyways I migrated over too allegro, and I am completely fascinated with it. There is only one thing I am missing here... I am really no good at programming difficult things such as physics, and I was wondering if there was a 2D physics engine out there somewhere. I have searched everywhere.... Any help would be appreciated.

thanks....

Baal Cadar · Post by **Baal Cadar** » Sun Apr 16, 2006 11:16 am

In Newton, you can create custom joints. These can be used, to remove degrees of freedom. So if you use it to prevent movement over the z-Axis, then this is more or less 2D-Physics. I believe this already has been done, you could search their forum about it over at http://newtondynamics.com

Eternl Knight · Post by **Eternl Knight** » Mon Apr 17, 2006 12:12 am

Most physics engines come with a default (i.e. pre-coded) joint type called a "hinge joint". This is what you are after I believe.

Depending on your needs - you might not need a full-blown physics engine however just to solve this. If this is the case, I can dig up some 2d physics sites/info for you to help you with this.

--EK

Guest · Post by **Guest** » Mon Apr 17, 2006 12:50 am

well I have a pixel by pixel collision detection library that was specifically for allegro and SDL. However I can't find a physics engine for SDL or allegro. I mean it is probably easy but I wish i could find one it would save me a lot of time. Also I need a full-blown physics engine. I wan't to be able to set gravity and have solid blocks to keep the object from falling offscreen basic things to that affect. Reason so is because I would like to create a game almost identical to soldat. Only It won't be based on soldiers. It will have a wide range of different characters such a fat guy with a trucker hat, a house-wife, and etc. And they will have an extensive collection of arsenal, and a jetpack for easy getting around. Reason being because the soldat game is very popular and well-made but the physics just don't feel right. I would like to improve on that note.

So to get back to the point, Yeah a full blown 2d physics engine would be nice.
I'll keep searching unless anyone else knows different.

Thanks...

Eternl Knight · Post by **Eternl Knight** » Mon Apr 17, 2006 2:07 am

Well the source code to a "full-blown 2D physics engine" was made available by Erin Catto at this year's GDC. It also includes a presentation on the math used for it.

It is a very good engine (but it is 2D only) using impulses for everything (including friction). I think Gamasutra (.com) is ow the official cache of all things GDC - so have a look for Erin's presentation over in their archives - the source code is included with the PowerPoint presentation.

--EK

Guest · Post by **Guest** » Tue Apr 18, 2006 5:30 am

Baal Cadar wrote:In Newton, you can create custom joints.

some people do not like it, but it is actually truth you can make a 2d game with an engine based on real laws of physics (force, torque, and constraint forces)
http://www.pedestrianentertainment.com/ ... igade_main