Fix cluster and incend OB not respecting ceiling protections (#4746)

# About the pull request

This PR makes it so incend and cluster OBs actually respect ceiling
protections (not just pylon protections). HE already is respecting
closed areas, so your fault for leaving the doors open.

# Explain why it's good for the game

Dropships ceilings were changed fairly long ago to protect against OBs,
but the implementation I guess was never tested thoroughly.

# Testing Photographs and Procedure
<details>
<summary>Screenshots & Videos</summary>


![incend](https://github.com/cmss13-devs/cmss13/assets/76988376/76907e59-d95d-4ddd-8165-864fa688e8c6)

https://youtu.be/Fc0q9p6hmeE

</details>


# Changelog
:cl: Drathek
fix: Fix incend and cluster OBs not respecting ceiling OB protections.
/:cl:

code/__DEFINES/__game.dm

@@ -283,7 +283,6 @@ block( \
 /// Only use the CEILING_PROTECTION_TIER_X defines for `protection_level`
 #define CEILING_IS_PROTECTED(ceiling, protection_level) (ceiling >= protection_level)
 
-
 // Default font settings
 #define FONT_SIZE "5pt"
 #define DEFAULT_FONT_COLOR "#09f"
@@ -493,6 +492,18 @@ block( \
 #define TURF_PROTECTION_CAS 2
 #define TURF_PROTECTION_OB 3
 
+/// Convert a turf protection level to a ceiling protection level
+/proc/get_ceiling_protection_level(turf_protection_level)
+	switch(turf_protection_level)
+		if(TURF_PROTECTION_OB)
+			return CEILING_PROTECTION_TIER_4
+		if(TURF_PROTECTION_CAS)
+			return CEILING_PROTECTION_TIER_3
+		if(TURF_PROTECTION_MORTAR)
+			return CEILING_PROTECTION_TIER_2
+		else
+			return CEILING_NO_PROTECTION
+
 // Anything above the deck boundary is the upper deck, anything below is the lower deck
 // This is exclusive, so anything ON the boundary is an edge case that's neither on the upper nor the lower deck
 #define ALMAYER_DECK_BOUNDARY 101

code/modules/cm_marines/orbital_cannon.dm

@@ -538,10 +538,14 @@ var/list/ob_type_fuel_requirements
 
 	for(var/i = 1 to total_amount)
 		for(var/k = 1 to instant_amount)
-			var/turf/U = pick(turf_list)
-			if(protected_by_pylon(TURF_PROTECTION_OB, U)) //If the turf somehow gained OB protection while the cluster was firing
+			var/turf/selected_turf = pick(turf_list)
+			if(protected_by_pylon(TURF_PROTECTION_OB, selected_turf))
 				continue
-			fire_in_a_hole(U)
+			var/area/selected_area = get_area(selected_turf)
+			if(CEILING_IS_PROTECTED(selected_area?.ceiling, CEILING_PROTECTION_TIER_4))
+				continue
+			fire_in_a_hole(selected_turf)
+
 		sleep(delay_between_clusters)
 	QDEL_IN(src, 5 SECONDS) // Leave time for last handle_ob_shake below
 

code/modules/projectiles/guns/flamer/flamer.dm

@@ -719,12 +719,12 @@ GLOBAL_LIST_EMPTY(flamer_particles)
 	var/direction_angle = dir2angle(direction)
 	var/obj/flamer_fire/foundflame = locate() in target
 	if(!foundflame)
-		var/datum/reagent/R = new()
-		R.intensityfire = burn_lvl
-		R.durationfire = fire_lvl
-		R.burn_sprite = burn_sprite
-		R.burncolor = f_color
-		new/obj/flamer_fire(target, cause_data, R)
+		var/datum/reagent/fire_reag = new()
+		fire_reag.intensityfire = burn_lvl
+		fire_reag.durationfire = fire_lvl
+		fire_reag.burn_sprite = burn_sprite
+		fire_reag.burncolor = f_color
+		new/obj/flamer_fire(target, cause_data, fire_reag)
 	if(target.density)
 		return
 
@@ -751,33 +751,41 @@ GLOBAL_LIST_EMPTY(flamer_particles)
 		if (spread_power < 1)
 			continue
 
-		var/turf/T = get_step(target, spread_direction)
+		var/turf/picked_turf = get_step(target, spread_direction)
 
-		if(!T) //prevents trying to spread into "null" (edge of the map?)
+		if(!picked_turf) //prevents trying to spread into "null" (edge of the map?)
 			continue
 
-		if(aerial_flame_level && (T.get_pylon_protection_level() >= aerial_flame_level))
-			break
+		if(aerial_flame_level)
+			if(picked_turf.get_pylon_protection_level() >= aerial_flame_level)
+				break
+			var/area/picked_area = get_area(picked_turf)
+			if(CEILING_IS_PROTECTED(picked_area?.ceiling, get_ceiling_protection_level(aerial_flame_level)))
+				break
 
 		spawn(0)
-			fire_spread_recur(T, cause_data, spread_power, spread_direction, fire_lvl, burn_lvl, f_color, burn_sprite, aerial_flame_level)
+			fire_spread_recur(picked_turf, cause_data, spread_power, spread_direction, fire_lvl, burn_lvl, f_color, burn_sprite, aerial_flame_level)
 
 /proc/fire_spread(turf/target, datum/cause_data/cause_data, range, fire_lvl, burn_lvl, f_color, burn_sprite = "dynamic", aerial_flame_level = TURF_PROTECTION_NONE)
-	var/datum/reagent/R = new()
-	R.intensityfire = burn_lvl
-	R.durationfire = fire_lvl
-	R.burn_sprite = burn_sprite
-	R.burncolor = f_color
+	var/datum/reagent/fire_reag = new()
+	fire_reag.intensityfire = burn_lvl
+	fire_reag.durationfire = fire_lvl
+	fire_reag.burn_sprite = burn_sprite
+	fire_reag.burncolor = f_color
 
-	new/obj/flamer_fire(target, cause_data, R)
+	new/obj/flamer_fire(target, cause_data, fire_reag)
 	for(var/direction in alldirs)
 		var/spread_power = range
 		switch(direction)
 			if(NORTH,SOUTH,EAST,WEST)
 				spread_power--
 			else
 				spread_power -= 1.414 //diagonal spreading
-		var/turf/T = get_step(target, direction)
-		if(aerial_flame_level && (T.get_pylon_protection_level() >= aerial_flame_level))
-			continue
-		fire_spread_recur(T, cause_data, spread_power, direction, fire_lvl, burn_lvl, f_color, burn_sprite, aerial_flame_level)
+		var/turf/picked_turf = get_step(target, direction)
+		if(aerial_flame_level)
+			if(picked_turf.get_pylon_protection_level() >= aerial_flame_level)
+				continue
+			var/area/picked_area = get_area(picked_turf)
+			if(CEILING_IS_PROTECTED(picked_area?.ceiling, get_ceiling_protection_level(aerial_flame_level)))
+				continue
+		fire_spread_recur(picked_turf, cause_data, spread_power, direction, fire_lvl, burn_lvl, f_color, burn_sprite, aerial_flame_level)