Defrag: Collision issues affecting overbounces

[chovelyoukai]

Describe the bug

When investigating #2034 it was found that some overbounce heights don't work in the test map. #2132 also reports that some ceiling OBs don't work. There could be multiple problems here but at least one issue is that collision detection in defrag allows the player to get too close to surfaces (within the distance epsilon) compared to other modes and to q3df. Possibly related to #2142

How To Reproduce

Try to OB in the defrag test map at the heights listed in #2034

Issue Map

df_tests

Expected Behavior

An overbounce should happen when the overbounce fix is disabled.

Operating System

N/A