Monday, June 18, 2007

Collisions


Ember uses Opcode (coupled to Ogre through OgreOpcode) for mouse picking. Opcode is a generic collision detection library and could probably be useful for many different things, but currently it's only used for mouse picking. The version used is however many moons too old and also a WIP prerelease. I've been itching for some time to upgrade to a more modern and robust version. One of the things that I've missed is the ability to do raychecks without backface culling. Not being able to do that results in not being able to pick the market stalls from behind, since the fabric is a single face where the material has backface culling turned off.
This weekend I finally took care of this nagging issue by upgrading to the latest version of OgreOpcode. It took 2h to upgrade the code, and then 4h of hunting down why no symbols could be found after the update. It turned out that it's not a good idea to use "," as delimiter in Makefile.am files (instead of the preferred " " version). Ah, the joys of stupidity.
Opcode is however not actively developed, and uses some dodgy "optimization" techniques, resulting in the code being nigh unreadable. It's working for me right now though, but if we in the future get cramped by it it might be wise to pursue other options such as Bullet.
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