A_Fall is an action that changes the actor's flags. This action was originally used in Doom by the player and enemies to make them intangible when they died (removing the flag
MF_SOLID to do so). In SRB2, it is exclusively used by players who have died, additionally adding the flags
MF_NOGRAVITY to allow them to fall through the floor.
Code – A_Fall
// Function: A_Fall
// Description: Changes a dying object's flags to reflect its having fallen to the ground.
// var1 = unused
// var2 = unused
void A_Fall(mobj_t *actor)
if (LUA_CallAction("A_Fall", actor))
// actor is on ground, it can be walked over
actor->flags &= ~MF_SOLID;
// fall through the floor
actor->flags |= MF_NOCLIP|MF_NOCLIPHEIGHT|MF_NOGRAVITY;
// So change this if corpse objects
// are meant to be obstacles.