Box2D Forums

Hello. I'm new to the forum.

[spelling edited here]
I'm going to start the story....
I'm building a simple 2D OpenGL Game Engine to the college dissertation.

A part of this Engine is an integration with an Physics Lib/Engine. Steps:

- I have built a class that holds and initialize the b2World:

- This class have a method to simple create box fixture


- I have simple compiled Box2D 2.2.1 as static library with Eclipse Indigo (CDT -> GNU GCC) on MacOSX Leopard 10.5 [<- its Leopard not Lion that makes all difference].
And then compiled the engine and test app projects (Success).

- The engine test application is very simple:
A Rocket as body with type 'b2_dynamicBody' and box shape on fixture
and 2 more bodies with 'b2_staticBody' body type.
One fixture per body.

- The engine is cross and then compiled on windows (Eclipse Indigo -> MinGW).
And there no problems at all. Only MacOSX Lion problems related.

- The problem is occurring during the execution process:
Assertion failed: (s_initialized == true), function Destroy, file ../Box2D/Dynamics/Contacts/b2Contact.cpp, line 103.

When the rocket collides with static bodies everything is ok and work. But when he leaves the collision the problem reaches.
This means that b2Contact wasn't initialized or 's_initialized' flag !? And then don't know why it occurs only on Mac.

It looks a simple problem, maybe a mistake.
Any light ?
Thanks everything.

Guys, i'm here to feedback about the problem.

After aloooooooooootttt of tests, i've found a way to cause and fix the problem. So.. I think i found the solution.

My Game uses my engine called HGEngine that helps me to manage the Box2D elements (initialize, convert values, add fixtures, process steps)

The engine is an Shared Library that compiles using Box2D static library.

The Game need to compile referencing the engine -lHGEngine and Box2D.

The problem is caused when Box2D is referenced before the engine on game compilation. I've changed the order of library references compile and execute, so everything goes fine.

I've saw Box2D works with static values, like this s_initialize. So maybe the compiler was creating a reference for s_initialize to the Engine different than s_initialize reference to the game, so it has no effect to the execution.

Thanks. Sorry for the bad english.

I would really like to know how you got Box2D to build and work under Eclipse in Mac OSX 10.6.8. I am not that experienced with CMake and I cant use Xcode 4. A short tutorial would really help.