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/__DEFINES/flags.dm

@@ -63,12 +63,10 @@
 
 #define OVERLAY_QUEUED_2		(1<<12)
 
-#define CHECK_RICOCHET_2		(1<<13)
-
 /// should the contents of this atom be acted upon
-#define RAD_PROTECT_CONTENTS_2	(1<<14)
+#define RAD_PROTECT_CONTENTS_2		(1<<14)
 /// should this object be allowed to be contaminated
-#define RAD_NO_CONTAMINATE_2	(1<<15)
+#define RAD_NO_CONTAMINATE_2		(1<<15)
 /// Prevents shuttles from deleting the item
 #define IMMUNE_TO_SHUTTLECRUSH_2 	(1<<16)
 /// Prevents malf AI animate + overload ability
@@ -80,6 +78,12 @@
 /// This flag allows for wearing of a belt item, even if you're not wearing a jumpsuit
 #define ALLOW_BELT_NO_JUMPSUIT_2	(1<<20)
 
+// /atom ricochet flags
+/// If the thing can reflect light (lasers/energy)
+#define RICOCHET_SHINY	(1<<0)
+/// If the thing can reflect matter (bullets/bomb shrapnel)
+#define RICOCHET_HARD 	(1<<1)
+
 //Reagent flags
 #define REAGENT_NOREACT			1
 

code/game/atoms.dm

@@ -4,6 +4,8 @@
 	var/level = 2
 	var/flags = NONE
 	var/flags_2 = NONE
+	/// how the atom should handle ricochet behavior
+	var/flags_ricochet = NONE
 	var/list/fingerprints
 	var/list/fingerprintshidden
 	var/fingerprintslast = null
@@ -107,6 +109,11 @@
 	/// Contains the world.time of when we start dragging something with our mouse. Used to prevent weird situations where you fail to click on something
 	var/drag_start = 0
 
+	///When a projectile tries to ricochet off this atom, the projectile ricochet chance is multiplied by this
+	var/receive_ricochet_chance_mod = 1
+	///When a projectile ricochets off this atom, it deals the normal damage * this modifier to this atom
+	var/receive_ricochet_damage_coeff = 0.33
+
 /atom/New(loc, ...)
 	SHOULD_CALL_PARENT(TRUE)
 	if(GLOB.use_preloader && (src.type == GLOB._preloader.target_path))//in case the instanciated atom is creating other atoms in New()
@@ -1107,8 +1114,20 @@ GLOBAL_LIST_EMPTY(blood_splatter_icons)
 /atom/proc/zap_act(power, zap_flags)
 	return
 
-/atom/proc/handle_ricochet(obj/item/projectile/P)
-	return
+/atom/proc/handle_ricochet(obj/item/projectile/ricocheting_projectile)
+	var/turf/p_turf = get_turf(ricocheting_projectile)
+	var/face_direction = get_dir(src, p_turf) || get_dir(src, ricocheting_projectile)
+	var/face_angle = dir2angle(face_direction)
+	var/incidence_s = GET_ANGLE_OF_INCIDENCE(face_angle, (ricocheting_projectile.Angle + 180))
+	var/a_incidence_s = abs(incidence_s)
+	if(a_incidence_s > 90 && a_incidence_s < 270)
+		return FALSE
+	if((ricocheting_projectile.flag in list(BULLET, BOMB)) && ricocheting_projectile.ricochet_incidence_leeway)
+		if((a_incidence_s < 90 && a_incidence_s < 90 - ricocheting_projectile.ricochet_incidence_leeway) || (a_incidence_s > 270 && a_incidence_s -270 > ricocheting_projectile.ricochet_incidence_leeway))
+			return FALSE
+	var/new_angle_s = SIMPLIFY_DEGREES(face_angle + incidence_s)
+	ricocheting_projectile.set_angle(new_angle_s)
+	return TRUE
 
 //This proc is called on the location of an atom when the atom is Destroy()'d
 /atom/proc/handle_atom_del(atom/A)

code/game/machinery/machinery.dm

@@ -7,6 +7,8 @@
 	layer = BELOW_OBJ_LAYER
 	armor = list(melee = 25, bullet = 10, laser = 10, energy = 0, bomb = 0, rad = 0, fire = 50, acid = 70)
 	atom_say_verb = "beeps"
+	flags_ricochet = RICOCHET_HARD
+	receive_ricochet_chance_mod = 0.3
 	var/stat = 0
 
 	/// How is this machine currently passively consuming power?

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

code/game/turfs/simulated/walls.dm

@@ -24,6 +24,7 @@
 	explosion_block = 1
 
 	flags_2 = RAD_PROTECT_CONTENTS_2 | RAD_NO_CONTAMINATE_2
+	flags_ricochet = RICOCHET_HARD
 	rad_insulation = RAD_MEDIUM_INSULATION
 
 	thermal_conductivity = WALL_HEAT_TRANSFER_COEFFICIENT
@@ -154,17 +155,6 @@
 	else
 		update_icon()
 
-/turf/simulated/wall/handle_ricochet(obj/item/projectile/P)			//A huge pile of shitcode!
-	var/turf/p_turf = get_turf(P)
-	var/face_direction = get_dir(src, p_turf)
-	var/face_angle = dir2angle(face_direction)
-	var/incidence_s = GET_ANGLE_OF_INCIDENCE(face_angle, (P.Angle + 180))
-	if(abs(incidence_s) > 90 && abs(incidence_s) < 270)
-		return FALSE
-	var/new_angle_s = SIMPLIFY_DEGREES(face_angle + incidence_s)
-	P.set_angle(new_angle_s)
-	return TRUE
-
 /turf/simulated/wall/dismantle_wall(devastated = FALSE, explode = FALSE)
 	if(devastated)
 		devastate_wall()

code/game/turfs/simulated/walls_mineral.dm

@@ -220,7 +220,7 @@
 	icon_state = "plastinum_wall-0"
 	base_icon_state = "plastinum_wall"
 	explosion_block = 3
-	flags_2 = CHECK_RICOCHET_2
+	flags_ricochet = RICOCHET_SHINY | RICOCHET_HARD
 	sheet_type = /obj/item/stack/sheet/mineral/titanium
 	smoothing_flags = SMOOTH_BITMASK | SMOOTH_DIAGONAL_CORNERS
 	smoothing_groups = list(SMOOTH_GROUP_TITANIUM_WALLS, SMOOTH_GROUP_WINDOW_FULLTILE_SHUTTLE)

code/modules/events/blob/blob_structures/strong_blob.dm

@@ -61,16 +61,4 @@
 	brute_resist = 0.5
 	explosion_block = 2
 	point_return = 9
-	flags_2 = CHECK_RICOCHET_2
-
-/obj/structure/blob/shield/reflective/handle_ricochet(obj/item/projectile/P)
-	var/turf/p_turf = get_turf(P)
-	var/face_direction = get_dir(src, p_turf)
-	var/face_angle = dir2angle(face_direction)
-	var/incidence_s = GET_ANGLE_OF_INCIDENCE(face_angle, (P.Angle + 180))
-	if(abs(incidence_s) > 90 && abs(incidence_s) < 270)
-		return FALSE
-	var/new_angle_s = SIMPLIFY_DEGREES(face_angle + incidence_s)
-	P.set_angle(new_angle_s)
-	visible_message("<span class='warning'>[P] reflects off [src]!</span>")
-	return TRUE
+	flags_ricochet = RICOCHET_SHINY

code/modules/projectiles/projectile_base.dm

@@ -66,9 +66,6 @@
 	var/immolate = 0
 	var/dismemberment = 0 //The higher the number, the greater the bonus to dismembering. 0 will not dismember at all.
 	var/impact_effect_type //what type of impact effect to show when hitting something
-	var/ricochets = 0
-	var/ricochets_max = 2
-	var/ricochet_chance = 30
 
 	var/log_override = FALSE //whether print to admin attack logs or just keep it in the diary
 
@@ -114,6 +111,27 @@
 	var/impact_light_color_override
 	var/hitscan_duration = 0.3 SECONDS
 
+	/// how many times we've ricochet'd so far (instance variable, not a stat)
+	var/ricochets = 0
+	/// how many times we can ricochet max
+	var/ricochets_max = 0
+	/// how many times we have to ricochet min (unless we hit an atom we can ricochet off)
+	var/min_ricochets = 0
+	/// 0-100 (or more, I guess), the base chance of ricocheting, before being modified by the atom we shoot and our chance decay
+	var/ricochet_chance = 0
+	/// 0-1 (or more, I guess) multiplier, the ricochet_chance is modified by multiplying this after each ricochet
+	var/ricochet_decay_chance = 0.7
+	/// 0-1 (or more, I guess) multiplier, the projectile's damage is modified by multiplying this after each ricochet
+	var/ricochet_decay_damage = 0.7
+	/// On ricochet, if nonzero, we consider all mobs within this range of our projectile at the time of ricochet to home in on like Revolver Ocelot, as governed by ricochet_auto_aim_angle
+	var/ricochet_auto_aim_range = 0
+	/// On ricochet, if ricochet_auto_aim_range is nonzero, we'll consider any mobs within this range of the normal angle of incidence to home in on, higher = more auto aim
+	var/ricochet_auto_aim_angle = 30
+	/// the angle of impact must be within this many degrees of the struck surface, set to 0 to allow any angle
+	var/ricochet_incidence_leeway = 40
+	/// Can our ricochet autoaim hit our firer?
+	var/ricochet_shoots_firer = TRUE
+
 /obj/item/projectile/New()
 	return ..()
 
@@ -429,7 +447,21 @@
 
 
 /obj/item/projectile/proc/on_ricochet(atom/A)
-	return
+	if(!ricochet_auto_aim_angle || !ricochet_auto_aim_range)
+		return
+
+	var/mob/living/unlucky_sob
+	var/best_angle = ricochet_auto_aim_angle
+	for(var/mob/living/L in range(ricochet_auto_aim_range, src.loc))
+		if(L.stat == DEAD || !isInSight(src, L) || (!ricochet_shoots_firer && L == firer))
+			continue
+		var/our_angle = abs(closer_angle_difference(Angle, get_angle(src.loc, L.loc)))
+		if(our_angle < best_angle)
+			best_angle = our_angle
+			unlucky_sob = L
+
+	if(unlucky_sob)
+		set_angle(get_angle(src, unlucky_sob.loc))
 
 /obj/item/projectile/proc/check_ricochet()
 	if(prob(ricochet_chance))
@@ -437,8 +469,12 @@
 	return FALSE
 
 /obj/item/projectile/proc/check_ricochet_flag(atom/A)
-	if(A.flags_2 & CHECK_RICOCHET_2)
+	if((flag in list(ENERGY, LASER)) && (A.flags_ricochet & RICOCHET_SHINY))
 		return TRUE
+
+	if((flag in list(BOMB, BULLET)) && (A.flags_ricochet & RICOCHET_HARD))
+		return TRUE
+
 	return FALSE
 
 /obj/item/projectile/set_angle(new_angle)