I just added crouching to my game, which obviously changes the bounding box of the player. For some reason, whenever the player crouches while moving up a slope, he's not able to move forward for a few seconds. I played around with this, and it's obvious that this has to do with the bounding box changing, but I can't seem to find anything in my code that would cause this, making me believe that this is simply how the engine works.

What happens when an entity has it's bounding box changed? Could this be the reason the player can not move upwards for a bit? Can I get around this?

i´m sure, that the bounding box is going inside the ground. make sure that this doesn´t happen.

If your bounding box is touching the slope then that could be it. The bounding box should only go down to about knee height. Use c_trace (with Use_box set) to add gravity and keep the feet on the ground.

I'm already using c_trace with USE_BOX to take care of all the slope walking and stair climbing, but the bounding box still goes to the feet because otherwise there are problems with getting stuck on ledges, and I would need another bounding box to make sure bullets could hit the player's feet. Anyway, wouldn't changing the bounding box change how USE_BOX affects the c_trace? This might be the problem.

I attempted to change the bounding box right before the main c_trace, and then change it back, but that just screwed it all up.

EDIT: Although, it seems that you're right. The bounding box is simply getting stuck, but that seems weird. I'm only changing the top of the bounding box, not the bottom.

Take a look at my website, there is a working crouching example, it might help.

Alright, fortunately I separated how vertical movement worked in to 2 "modes," depending on if you're on flat ground or a slope. So, it was very easy to add in the slope section that if the player is crouching, player.z should = on the slope (rather than a bit below it), making him unstuck. Thanks everyone!