Refactors projectile ricochets (#25764)

* same taste, twice the speed

* pulls proc/handle_ricochet() to the atom level. adds var/flags_ricochet and related defines.

* space indentation sneaks its way in yet again

---------

Co-authored-by: Luc <89928798+lewcc@users.noreply.github.com>

code/game/objects/objs.dm

@@ -115,7 +115,7 @@
 			air = environment
 		if(isnull(air))
 			return
-		
+
 		var/breath_percentage = BREATH_VOLUME / air.return_volume()
 		return air.remove(air.total_moles() * breath_percentage)
 	else
@@ -303,6 +303,12 @@
 	else
 		C.KnockDown(3 SECONDS)
 
+/obj/handle_ricochet(obj/item/projectile/P)
+	. = ..()
+	if(. && receive_ricochet_damage_coeff)
+		// pass along receive_ricochet_damage_coeff damage to the structure for the ricochet
+		take_damage(P.damage * receive_ricochet_damage_coeff, P.damage_type, P.flag, 0, REVERSE_DIR(P.dir), P.armour_penetration_flat, P.armour_penetration_percentage)
+
 /obj/proc/return_obj_air()
 	RETURN_TYPE(/datum/gas_mixture)
 	if(isobj(loc))

code/game/objects/structures.dm

@@ -3,6 +3,8 @@
 	pressure_resistance = 8
 	max_integrity = 300
 	face_while_pulling = TRUE
+	flags_ricochet = RICOCHET_HARD
+	receive_ricochet_chance_mod = 0.6
 	var/climbable
 	/// Determines if a structure adds the TRAIT_TURF_COVERED to its turf.
 	var/creates_cover = FALSE

code/game/objects/structures/window.dm

@@ -8,6 +8,8 @@
 	anchored = TRUE
 	flags = ON_BORDER
 	flags_2 = RAD_PROTECT_CONTENTS_2
+	flags_ricochet = RICOCHET_HARD
+	receive_ricochet_chance_mod = 0.5
 	can_be_unanchored = TRUE
 	max_integrity = 25
 	resistance_flags = ACID_PROOF