Mecha HUD hiding

Hides the user's inventory (as per F12) when they enter a mecha, since it is essentially unusable.  Pressing F12 will reveal it, as will exiting the mecha.  If your inventory is hidden before you enter the mech, it will remain hidden when you leave.

code/_onclick/hud/hud.dm

@@ -186,52 +186,70 @@ datum/hud/New(mob/owner)
 	else if(isovermind(mymob))
 		blob_hud()
 
+	if(istype(mymob.loc,/obj/mecha))
+		hide_hud()
+
+
+/datum/hud/proc/hide_hud() // hide hands is not currently used by anything but could be
+	if(!ismob(mymob))
+		return 0
+	if(!mymob.client)
+		return 0
+	if(hud_shown)
+		hud_shown = 0
+		if(adding)
+			mymob.client.screen -= adding
+		if(other)
+			mymob.client.screen -= other
+		if(hotkeybuttons)
+			mymob.client.screen -= hotkeybuttons
+		if(item_action_list)
+			mymob.client.screen -= item_action_list
+
+		//These ones are not a part of 'adding', 'other' or 'hotkeybuttons' but we want them gone.
+		mymob.client.screen -= mymob.zone_sel	//zone_sel is a mob variable for some reason.
+
+		//These ones are a part of 'adding', 'other' or 'hotkeybuttons' but we want them to stay
+		mymob.client.screen += l_hand_hud_object	//we want the hands to be visible
+		mymob.client.screen += r_hand_hud_object	//we want the hands to be visible
+		mymob.client.screen += action_intent		//we want the intent swticher visible
+		action_intent.screen_loc = ui_acti_alt	//move this to the alternative position, where zone_select usually is.
+
+		hidden_inventory_update()
+		persistant_inventory_update()
+		mymob.update_action_buttons()
+
+/datum/hud/proc/show_hud()
+	if(!ismob(mymob))
+		return 0
+	if(!mymob.client)
+		return 0
+	if(!hud_shown)
+		hud_shown = 1
+		if(adding)
+			mymob.client.screen += adding
+		if(other && inventory_shown)
+			mymob.client.screen += other
+		if(hotkeybuttons && !hotkey_ui_hidden)
+			mymob.client.screen += hotkeybuttons
+
+		action_intent.screen_loc = ui_acti //Restore intent selection to the original position
+		mymob.client.screen += mymob.zone_sel				//This one is a special snowflake
+		hidden_inventory_update()
+		persistant_inventory_update()
+		mymob.update_action_buttons()
+
 //Triggered when F12 is pressed (Unless someone changed something in the DMF)
 /mob/verb/button_pressed_F12()
 	set name = "F12"
 	set hidden = 1
 
-	if(hud_used)
+	if(hud_used && client)
 		if(ishuman(src))
-			if(!src.client) return
-
 			if(hud_used.hud_shown)
-				hud_used.hud_shown = 0
-				if(src.hud_used.adding)
-					src.client.screen -= src.hud_used.adding
-				if(src.hud_used.other)
-					src.client.screen -= src.hud_used.other
-				if(src.hud_used.hotkeybuttons)
-					src.client.screen -= src.hud_used.hotkeybuttons
-				if(src.hud_used.item_action_list)
-					src.client.screen -= src.hud_used.item_action_list
-
-				//Due to some poor coding some things need special treatment:
-				//These ones are a part of 'adding', 'other' or 'hotkeybuttons' but we want them to stay
-				src.client.screen += src.hud_used.l_hand_hud_object	//we want the hands to be visible
-				src.client.screen += src.hud_used.r_hand_hud_object	//we want the hands to be visible
-				src.client.screen += src.hud_used.action_intent		//we want the intent swticher visible
-				src.hud_used.action_intent.screen_loc = ui_acti_alt	//move this to the alternative position, where zone_select usually is.
-
-				//These ones are not a part of 'adding', 'other' or 'hotkeybuttons' but we want them gone.
-				src.client.screen -= src.zone_sel	//zone_sel is a mob variable for some reason.
-
+				hud_used.hide_hud()
 			else
-				hud_used.hud_shown = 1
-				if(src.hud_used.adding)
-					src.client.screen += src.hud_used.adding
-				if(src.hud_used.other && src.hud_used.inventory_shown)
-					src.client.screen += src.hud_used.other
-				if(src.hud_used.hotkeybuttons && !src.hud_used.hotkey_ui_hidden)
-					src.client.screen += src.hud_used.hotkeybuttons
-
-
-				src.hud_used.action_intent.screen_loc = ui_acti //Restore intent selection to the original position
-				src.client.screen += src.zone_sel				//This one is a special snowflake
-
-			hud_used.hidden_inventory_update()
-			hud_used.persistant_inventory_update()
-			update_action_buttons()
+				hud_used.show_hud()
 		else
 			usr << "\red Inventory hiding is currently only supported for human mobs, sorry."
 	else

code/game/mecha/mecha.dm

@@ -38,6 +38,7 @@
 	var/datum/effect/effect/system/spark_spread/spark_system = new
 	var/lights = 0
 	var/lights_power = 6
+	var/last_user_hud = 1 // used to show/hide the mecha hud while preserving previous preference
 
 	//inner atmos
 	var/use_internal_tank = 0
@@ -1000,6 +1001,10 @@
 		*/
 		H.stop_pulling()
 		H.forceMove(src)
+		if(H.hud_used)
+			last_user_hud = H.hud_used.hud_shown
+			H.hud_used.hide_hud()
+
 		src.occupant = H
 		src.add_fingerprint(H)
 		src.forceMove(src.loc)
@@ -1145,6 +1150,9 @@
 			src.occupant.client.perspective = MOB_PERSPECTIVE
 		*/
 		src.occupant << browse(null, "window=exosuit")
+		if(src.occupant.hud_used && src.last_user_hud)
+			src.occupant.hud_used.show_hud()
+
 		if(istype(mob_container, /obj/item/device/mmi))
 			var/obj/item/device/mmi/mmi = mob_container
 			if(mmi.brainmob)