thanks for taking the time to read my question.
I'm writing a 2d top-down shooter game. It is currently using Box2d as a physics engine. The thing is, it isn't really using Box2d to it's fullest potential, just for collision detection and the underlying velocity/rotation update loop. Any plans to add real physics would simply be eye-candy, not a game changer.
Now I chose Box2d because I went through 2 other physics engines, and they just couldn't handle the types of collisions I'm detecting. I'm creating several 'bullets' with very high velocities, and I do not want them to be instant hits on their targets. JigLib and Flixel both had the same problem - bullets were not overlapping enemies at the time of the frame update, and thus were not detected as collisions (i.e. the bullets passed through enemies because they moved to fast).
I moved to Box2d because of it's iterative collision sampling, as well as the SetAsBullet method on bodies. And it works great! But now Box2d is giving me troubles too - generating several bullets per second, or at the same time, is severely lowering my fps.
So I removed Box2d to confirm that it was not a rendering limitation... added my own velocity/rotation system, and I can fire hundreds of bullets per second. Great! But its lacking any sort of collision detection.
So the questions:
1) Should I write my own iterative collision engine?
2) Should I give Box2d a try again, perhaps with some tweaks to make adding new bodies faster?
3) Is there some other alternative, maybe a lightweight physics engine that specializes in this?
4) Do you know of any other techniques or design patterns that could be of use?
Thanks so much for your help!
Edit: I should note, there are not just bullets, but larger, slower projectiles as well. I considered ray casting a line segment to the projectile's previous position, and catching intersections, but that won't work for the larger objects :(
