adds a visible line when using iv drips / bloodpacks (#3645)

# About the pull request

https://forum.cm-ss13.com/t/giving-blood-shows-visible-line/2610
adds a line between the person receiving blood and where the blood is
coming from, similar to the phone cable

# Explain why it's good for the game

soul :]


# Testing Photographs and Procedure


https://github.com/cmss13-devs/cmss13/assets/54692343/e023add2-7172-4641-a64e-e60a313a9e1a


# Changelog
:cl:Khadd
add: added a iv tube between the user and the bloodpack / iv drip
imageadd: sprites for the iv tube
/:cl:

---------

Co-authored-by: harryob <[email protected]>
Co-authored-by: Drathek <[email protected]>

code/game/machinery/iv_drip.dm

@@ -4,13 +4,16 @@
 	anchored = FALSE
 	density = FALSE
 	drag_delay = 1
+	base_pixel_x = 15
+	base_pixel_y = -2
 
 	var/mob/living/carbon/attached = null
 	var/mode = 1 // 1 is injecting, 0 is taking blood.
 	var/obj/item/reagent_container/beaker = null
+	var/datum/beam/current_beam
 
 /obj/structure/machinery/iv_drip/update_icon()
-	if(src.attached)
+	if(attached)
 		icon_state = "hooked"
 	else
 		icon_state = ""
@@ -35,8 +38,31 @@
 			filling.color = mix_color_from_reagents(reagents.reagent_list)
 			overlays += filling
 
+/obj/structure/machinery/iv_drip/proc/update_beam()
+	if(current_beam)
+		QDEL_NULL(current_beam)
+	else if(!QDELETED(src) && attached)
+		current_beam = beam(attached, "iv_tube")
+
+/obj/structure/machinery/iv_drip/power_change()
+	. = ..()
+	if(stat & NOPOWER && attached)
+		visible_message("\The [src] retracts its IV tube and shuts down.")
+		attached.active_transfusions -= src
+		attached = null
+		update_beam()
+		update_icon()
+
+/obj/structure/machinery/iv_drip/Destroy()
+	attached?.active_transfusions -= src
+	update_beam()
+	. = ..()
+
 /obj/structure/machinery/iv_drip/MouseDrop(over_object, src_location, over_location)
 	..()
+	if(inoperable())
+		visible_message("\The [src] is not powered.")
+		return
 
 	if(ishuman(usr))
 		var/mob/living/carbon/human/H = usr
@@ -48,6 +74,7 @@
 			"You detach \the [src] from \the [attached].")
 			attached.active_transfusions -= src
 			attached = null
+			update_beam()
 			update_icon()
 			stop_processing()
 			return
@@ -57,6 +84,7 @@
 			"You attach \the [src] to \the [over_object].")
 			attached = over_object
 			attached.active_transfusions += src
+			update_beam()
 			update_icon()
 			start_processing()
 
@@ -81,6 +109,7 @@
 			log_admin("[key_name(user)] put a [beaker] into [src], containing [reagentnames] at ([src.loc.x],[src.loc.y],[src.loc.z]).")
 
 			to_chat(user, "You attach \the [W] to \the [src].")
+			update_beam()
 			update_icon()
 		return
 	else
@@ -97,6 +126,7 @@
 				attached.emote("scream")
 			attached.active_transfusions -= src
 			attached = null
+			update_beam()
 			update_icon()
 			stop_processing()
 			return

code/game/objects/items/reagent_containers/blood_pack.dm

@@ -13,7 +13,9 @@
 
 	var/mode = BLOOD_BAG_INJECTING
 	var/mob/living/carbon/human/connected_to
+	var/mob/living/carbon/human/connected_from
 	var/blood_type = null
+	var/datum/beam/current_beam
 
 /obj/item/reagent_container/blood/Initialize()
 	. = ..()
@@ -32,6 +34,12 @@
 		if(10 to 50) icon_state = "half"
 		if(51 to INFINITY) icon_state = "full"
 
+/obj/item/reagent_container/blood/proc/update_beam()
+	if(current_beam)
+		QDEL_NULL(current_beam)
+	else if(connected_from && connected_to)
+		current_beam = connected_from.beam(connected_to, "iv_tube")
+
 /obj/item/reagent_container/blood/attack(mob/attacked_mob, mob/user)
 	. = ..()
 
@@ -44,7 +52,10 @@
 		user.visible_message("[user] detaches [src] from [connected_to].", \
 			"You detach [src] from [connected_to].")
 		connected_to.active_transfusions -= src
+		connected_to.base_pixel_x = 0
 		connected_to = null
+		connected_from = null
+		update_beam()
 		return
 
 	if(!skillcheck(user, SKILL_SURGERY, SKILL_SURGERY_NOVICE))
@@ -60,10 +71,13 @@
 
 	if(istype(attacked_mob, /mob/living/carbon/human))
 		connected_to = attacked_mob
+		connected_from = user
 		connected_to.active_transfusions += src
+		connected_to.base_pixel_x = 5
 		START_PROCESSING(SSobj, src)
 		user.visible_message("[user] attaches \the [src] to [connected_to].", \
 			"You attach \the [src] to [connected_to].")
+		update_beam()
 
 /obj/item/reagent_container/blood/process()
 	//if we're not connected to anything stop doing stuff
@@ -106,6 +120,10 @@
 
 	connected_to.take_blood(src, amount)
 
+/obj/item/reagent_container/blood/dropped()
+	..()
+	bad_disconnect()
+
 ///Used to standardize effects of a blood bag disconnecting improperly
 /obj/item/reagent_container/blood/proc/bad_disconnect()
 	if(!connected_to)
@@ -116,7 +134,10 @@
 	if(connected_to.pain.feels_pain)
 		connected_to.emote("scream")
 	connected_to.active_transfusions -= src
+	connected_to.base_pixel_x = 0
 	connected_to = null
+	connected_from = null
+	update_beam()
 
 /obj/item/reagent_container/blood/verb/toggle_mode()
 	set category = "Object"