The great rock update.

code/game/objects/structures/ledges.dm

@@ -0,0 +1,85 @@
+/obj/structure/ledge
+	name = "rock ledge"
+	desc = "An easily scaleable rocky ledge."
+	icon = 'icons/obj/ledges.dmi'
+	density = 1
+	throwpass = 1
+	climbable = 1
+	anchored = 1
+	var/solidledge = 1
+	flags = ON_BORDER
+	layer = STAIRS_LAYER
+	icon_state = "ledge"
+
+/obj/structure/ledge_corner
+	icon_state = "ledge-corner"
+	flags = 0
+	name = "rock ledge"
+	desc = "An easily scaleable rocky ledge."
+	icon = 'icons/obj/ledges.dmi'
+	density = 1
+	throwpass = 1
+	climbable = 1
+	anchored = 1
+	layer = STAIRS_LAYER
+
+/obj/structure/ledge/ledge_nub
+	desc = "Part of a rocky ledge."
+	icon_state = "ledge-nub"
+	density = 0
+	solidledge = 0
+
+/obj/structure/ledge/ledge_stairs
+	name = "rock stairs"
+	desc = "A colorful set of rocky stairs"
+	icon_state = "ledge-stairs"
+	density = 0
+	solidledge = 0
+
+/obj/structure/ledge/CanPass(atom/movable/mover, turf/target)
+	if(istype(mover) && mover.checkpass(PASSTABLE))
+		return TRUE
+	if(solidledge && get_dir(mover, target) == turn(dir, 180))
+		return !density
+	return TRUE
+
+/obj/structure/ledge/CheckExit(atom/movable/O as mob|obj, target as turf)
+	if(istype(O) && O.checkpass(PASSTABLE))
+		return 1
+	if(solidledge && get_dir(O.loc, target) == dir)
+		return 0
+	return 1
+
+/obj/structure/ledge/do_climb(var/mob/living/user)
+	if(!can_climb(user))
+		return
+
+	usr.visible_message("<span class='warning'>[user] starts climbing onto \the [src]!</span>")
+	climbers |= user
+
+	if(!do_after(user,(issmall(user) ? 20 : 34)))
+		climbers -= user
+		return
+
+	if(!can_climb(user, post_climb_check=1))
+		climbers -= user
+		return
+
+	if(get_turf(user) == get_turf(src))
+		usr.forceMove(get_step(src, src.dir))
+	else
+		usr.forceMove(get_turf(src))
+
+	usr.visible_message("<span class='warning'>[user] climbed over \the [src]!</span>")
+	climbers -= user
+
+/obj/structure/ledge/can_climb(var/mob/living/user, post_climb_check=0)
+	if(!..())
+		return 0
+
+	if(get_turf(user) == get_turf(src))
+		var/obj/occupied = neighbor_turf_impassable()
+		if(occupied)
+			to_chat(user, "<span class='danger'>You can't climb there, there's \a [occupied] in the way.</span>")
+			return 0
+	return 1