Merge branch 'dev' of https://github.com/Baystation12/Baystation12 into fluff2

code/game/objects/items/weapons/material/bats.dm

@@ -10,6 +10,7 @@
 	default_material = "wood"
 	force_divisor = 1.1           // 22 when wielded with weight 20 (steel)
 	unwielded_force_divisor = 0.7 // 15 when unwielded based on above.
+	slot_flags = SLOT_BACK
 
 //Predefined materials go here.
 /obj/item/weapon/material/twohanded/baseballbat/metal/New(var/newloc)

code/game/objects/items/weapons/tanks/jetpack.dm

@@ -4,6 +4,7 @@
 	name = "jetpack (empty)"
 	desc = "A tank of compressed gas for use as propulsion in zero-gravity areas. Use with caution."
 	icon_state = "jetpack"
+	gauge_icon = null
 	w_class = 4.0
 	item_state = "jetpack"
 	distribute_pressure = ONE_ATMOSPHERE*O2STANDARD

code/game/objects/items/weapons/tanks/tank_types.dm

@@ -85,6 +85,7 @@
 	name = "phoron tank"
 	desc = "Contains dangerous phoron. Do not inhale. Warning: extremely flammable."
 	icon_state = "phoron"
+	gauge_icon = null
 	flags = CONDUCT
 	slot_flags = null	//they have no straps!
 
@@ -114,6 +115,8 @@
 	name = "emergency oxygen tank"
 	desc = "Used for emergencies. Contains very little oxygen, so try to conserve it until you actually need it."
 	icon_state = "emergency"
+	gauge_icon = "indicator_emergency"
+	gauge_cap = 4
 	flags = CONDUCT
 	slot_flags = SLOT_BELT
 	w_class = 2.0
@@ -142,12 +145,15 @@
 /obj/item/weapon/tank/emergency_oxygen/double
 	name = "double emergency oxygen tank"
 	icon_state = "emergency_double"
+	gauge_icon = "indicator_emergency_double"
 	volume = 10
 
 /obj/item/weapon/tank/emergency_nitrogen
 	name = "emergency nitrogen tank"
 	desc = "An emergency air tank hastily painted red and issued to Vox crewmembers."
 	icon_state = "emergency_nitro"
+	gauge_icon = "indicator_emergency"
+	gauge_cap = 4
 	flags = CONDUCT
 	slot_flags = SLOT_BELT
 	w_class = 2.0

code/game/objects/items/weapons/tanks/tanks.dm

@@ -1,9 +1,17 @@
 #define TANK_MAX_RELEASE_PRESSURE (3*ONE_ATMOSPHERE)
 #define TANK_DEFAULT_RELEASE_PRESSURE 24
+#define TANK_IDEAL_PRESSURE 1015 //Arbitrary.
+
+var/list/global/tank_gauge_cache = list()
 
 /obj/item/weapon/tank
 	name = "tank"
 	icon = 'icons/obj/tank.dmi'
+
+	var/gauge_icon = "indicator_tank"
+	var/last_gauge_pressure
+	var/gauge_cap = 6
+
 	flags = CONDUCT
 	slot_flags = SLOT_BACK
 	w_class = 3
@@ -31,8 +39,8 @@
 	src.air_contents = new /datum/gas_mixture()
 	src.air_contents.volume = volume //liters
 	src.air_contents.temperature = T20C
-
 	processing_objects.Add(src)
+	update_gauge()
 	return
 
 /obj/item/weapon/tank/Destroy()
@@ -220,8 +228,28 @@
 /obj/item/weapon/tank/process()
 	//Allow for reactions
 	air_contents.react() //cooking up air tanks - add phoron and oxygen, then heat above PHORON_MINIMUM_BURN_TEMPERATURE
+	if(gauge_icon)
+		update_gauge()
 	check_status()
 
+/obj/item/weapon/tank/proc/update_gauge()
+	var/gauge_pressure = 0
+	if(air_contents)
+		gauge_pressure = air_contents.return_pressure()
+		if(gauge_pressure > TANK_IDEAL_PRESSURE)
+			gauge_pressure = -1
+		else
+			gauge_pressure = round((gauge_pressure/TANK_IDEAL_PRESSURE)*gauge_cap)
+
+	if(gauge_pressure == last_gauge_pressure)
+		return
+
+	last_gauge_pressure = gauge_pressure
+	overlays.Cut()
+	var/indicator = "[gauge_icon][(gauge_pressure == -1) ? "overload" : gauge_pressure]"
+	if(!tank_gauge_cache[indicator])
+		tank_gauge_cache[indicator] = image(icon, indicator)
+	overlays += tank_gauge_cache[indicator]
 
 /obj/item/weapon/tank/proc/check_status()
 	//Handle exploding, leaking, and rupturing of the tank