Returns Darksight Functionality

Returns the ability to see in the dark. see_in_dark determines how far you can see into absolute darkness, both for examining tile contents and visuals.

code/modules/mob/living/carbon/alien/alien.dm

@@ -301,4 +301,5 @@ Des: Removes all infected images from the alien.
 			lighting_alpha = min(lighting_alpha, E.lighting_alpha)
 
 	SEND_SIGNAL(src, COMSIG_MOB_UPDATE_SIGHT)
-	sync_lighting_plane_alpha()
+	sync_lighting_plane_alpha()
+	sync_nightvision_screen()

code/modules/mob/living/carbon/carbon.dm

@@ -1165,3 +1165,4 @@ so that different stomachs can handle things in different ways VB*/
 
 	SEND_SIGNAL(src, COMSIG_MOB_UPDATE_SIGHT)
 	sync_lighting_plane_alpha()
+	sync_nightvision_screen()

code/modules/mob/living/carbon/human/human.dm

@@ -567,6 +567,7 @@
 	dna.species.update_sight(src)
 	SEND_SIGNAL(src, COMSIG_MOB_UPDATE_SIGHT)
 	sync_lighting_plane_alpha()
+	sync_nightvision_screen()
 
 //Added a safety check in case you want to shock a human mob directly through electrocute_act.
 /mob/living/carbon/human/electrocute_act(shock_damage, obj/source, siemens_coeff = 1, safety = FALSE, override = FALSE, tesla_shock = FALSE, illusion = FALSE, stun = TRUE)

code/modules/mob/living/carbon/human/species/_species.dm

@@ -717,6 +717,7 @@ It'll return null if the organ doesn't correspond, so include null checks when u
 		H.sight |= (SEE_TURFS|SEE_MOBS|SEE_OBJS)
 
 	H.sync_lighting_plane_alpha()
+	H.sync_nightvision_screen()
 
 /datum/species/proc/water_act(mob/living/carbon/human/M, volume, temperature, source)
 	if(abs(temperature - M.bodytemperature) > 10) //If our water and mob temperature varies by more than 10K, cool or/ heat them appropriately

code/modules/mob/living/life.dm

@@ -215,6 +215,7 @@
 	see_in_dark = 8
 	see_invisible = SEE_INVISIBLE_OBSERVER
 	sync_lighting_plane_alpha()
+	sync_nightvision_screen()
 
 /mob/living/proc/handle_hud_icons()
 	handle_hud_icons_health()

code/modules/mob/living/silicon/ai/ai.dm

@@ -1314,3 +1314,4 @@ var/list/ai_verbs_default = list(
 
 	SEND_SIGNAL(src, COMSIG_MOB_UPDATE_SIGHT)
 	sync_lighting_plane_alpha()
+	sync_nightvision_screen()

code/modules/mob/living/silicon/robot/robot.dm

@@ -1453,4 +1453,5 @@ var/list/robot_verbs_default = list(
 
 	SEND_SIGNAL(src, COMSIG_MOB_UPDATE_SIGHT)
 	sync_lighting_plane_alpha()
+	sync_nightvision_screen()
 	

code/modules/mob/mob.dm

@@ -1357,9 +1357,22 @@ var/list/slot_equipment_priority = list( \
 /mob/proc/update_sight()
 	SEND_SIGNAL(src, COMSIG_MOB_UPDATE_SIGHT)
 	sync_lighting_plane_alpha()
+	sync_nightvision_screen()
 
 /mob/proc/sync_lighting_plane_alpha()
 	if(hud_used)
 		var/obj/screen/plane_master/lighting/L = hud_used.plane_masters["[LIGHTING_PLANE]"]
-		if (L)
+		if(L)
 			L.alpha = lighting_alpha
+
+/mob/proc/sync_nightvision_screen()
+	var/obj/screen/fullscreen/see_through_darkness/S = screens["see_through_darkness"]
+	if(S)
+		var/suffix = ""
+		switch(see_in_dark)
+			if(3 to 8)
+				suffix = "_[see_in_dark]"
+			if(8 to INFINITY)
+				suffix = "_8"
+
+		S.icon_state = "[initial(S.icon_state)][suffix]"