POLARIS: Ventcrawling assistance

code/_onclick/hud/hud.dm

@@ -9,6 +9,7 @@ var/list/global_huds = list(
 		global_hud.whitense,
 		global_hud.vimpaired,
 		global_hud.darkMask,
+		global_hud.centermarker,
 		global_hud.nvg,
 		global_hud.thermal,
 		global_hud.meson,
@@ -27,6 +28,7 @@ var/list/global_huds = list(
 	var/obj/screen/whitense
 	var/list/vimpaired
 	var/list/darkMask
+	var/obj/screen/centermarker
 	var/obj/screen/darksight
 	var/obj/screen/nvg
 	var/obj/screen/thermal
@@ -72,6 +74,12 @@ var/list/global_huds = list(
 	darksight.plane = PLANE_LIGHTING
 	darksight.plane = LIGHTING_LAYER + 0.1
 
+	//Marks the center of the screen, for things like ventcrawl
+	centermarker = new /obj/screen()
+	centermarker.icon = 'icons/mob/screen1.dmi'
+	centermarker.icon_state = "centermarker"
+	centermarker.screen_loc = "CENTER,CENTER"
+
 	nvg = setup_overlay("nvg_hud")
 	thermal = setup_overlay("thermal_hud")
 	meson = setup_overlay("meson_hud")

code/modules/ventcrawl/ventcrawl.dm

@@ -35,6 +35,7 @@ var/list/ventcrawl_machinery = list(
 	if(is_ventcrawling && istype(loc, /obj/machinery/atmospherics)) //attach us back into the pipes
 		remove_ventcrawl()
 		add_ventcrawl(loc)
+		client.screen += global_hud.centermarker
 
 /mob/living/simple_animal/slime/can_ventcrawl()
 	if(victim)
@@ -182,6 +183,8 @@ var/list/ventcrawl_machinery = list(
 				A.pipe_image = image(A, A.loc, layer = 20, dir = A.dir)
 			pipes_shown += A.pipe_image
 			client.images += A.pipe_image
+	if(client)
+		client.screen += global_hud.centermarker
 
 /mob/living/proc/remove_ventcrawl()
 	is_ventcrawling = 0
@@ -189,6 +192,7 @@ var/list/ventcrawl_machinery = list(
 	if(client)
 		for(var/image/current_image in pipes_shown)
 			client.images -= current_image
+		client.screen -= global_hud.centermarker
 		client.eye = src
 
 	pipes_shown.len = 0