its a lil janky but we take those (#15834)

Co-authored-by: Hatterhat <Hatterhat@users.noreply.github.com>

code/_onclick/hud/_defines.dm

@@ -47,6 +47,7 @@
 #define ui_back "CENTER-2:14,SOUTH:5"
 #define ui_storage1 "CENTER+1:18,SOUTH:5"
 #define ui_storage2 "CENTER+2:20,SOUTH:5"
+#define ui_combo "CENTER+4:24,SOUTH+1:7" // combo meter for martial arts
 
 //Lower right, persistent menu
 #define ui_drop_throw "EAST-1:28,SOUTH+1:7"

code/_onclick/hud/hud.dm

@@ -33,6 +33,8 @@ GLOBAL_LIST_INIT(available_ui_styles, list(
 	var/atom/movable/screen/alien_plasma_display
 	var/atom/movable/screen/alien_queen_finder
 
+	var/atom/movable/screen/combo/combo_display
+
 	var/atom/movable/screen/devil/soul_counter/devilsouldisplay
 
 	var/atom/movable/screen/synth/coolant_counter/coolant_display
@@ -130,6 +132,7 @@ GLOBAL_LIST_INIT(available_ui_styles, list(
 	blobpwrdisplay = null
 	alien_plasma_display = null
 	alien_queen_finder = null
+	combo_display = null
 
 	QDEL_LIST_ASSOC_VAL(plane_masters)
 	QDEL_LIST(screenoverlays)

code/_onclick/hud/human.dm

@@ -461,6 +461,9 @@
 	zone_select.update_icon()
 	static_inventory += zone_select
 
+	combo_display = new /atom/movable/screen/combo()
+	infodisplay += combo_display
+
 	for(var/atom/movable/screen/inventory/inv in (static_inventory + toggleable_inventory))
 		if(inv.slot_id)
 			inv.hud = src

code/_onclick/hud/screen_objects.dm

@@ -720,3 +720,28 @@
 /atom/movable/screen/component_button/Click(params)
 	if(parent)
 		parent.component_click(src, params)
+
+/atom/movable/screen/combo
+	icon_state = ""
+	mouse_opacity = MOUSE_OPACITY_TRANSPARENT
+	screen_loc = ui_combo
+	layer = ABOVE_HUD_LAYER
+	var/timerid
+
+/atom/movable/screen/combo/proc/clear_streak()
+	cut_overlays()
+	icon_state = ""
+
+/atom/movable/screen/combo/update_icon_state(streak = "")
+	clear_streak()
+	if (timerid)
+		deltimer(timerid)
+	if (!streak)
+		return
+	timerid = addtimer(CALLBACK(src, .proc/clear_streak), 20, TIMER_UNIQUE | TIMER_STOPPABLE)
+	icon_state = "combo"
+	for (var/i = 1; i <= length(streak); ++i)
+		var/intent_text = copytext(streak, i, i + 1)
+		var/image/intent_icon = image(icon,src,"combo_[intent_text]")
+		intent_icon.pixel_x = 16 * (i - 1) - 8 * length(streak)
+		add_overlay(intent_icon)