pcx and pcy
These variables track the true center of the mob based on its bounding box. pcx and pcy stand for "Pixel Center X" and "Pixel Center Y" respectively.
//current workaround to make it work
set_pos(nx, ny, map_z = -1)
This makes it much less time consuming when handling cases which are calculated from the center of mobs instead of their positions on the map.
camera.offset_x and camera.offset_y
This is used to modify the camera position after all automated camera positioning via SLIDE or FOLLOW camera types.
This is useful for moments when you want to momentarily change the players bounding box without jiggling the camera about, or while the mod is in a cinematic. It can also be used to shake the screen to display rumbling or damage.