Vehicle projectile origin adjustment (#6245)

# About the pull request

Vehicle projectiles now start on the vehicle and travel outward, without
hitting the vehicle. As a side effect, `Adjacent()` checks now accept a
list of objects to ignore.

Origins are adjusted to the point visually closest to the hardpoint's
sprite. For most hardpoints this is the center of the vehicle, with the
only exceptions being the APC weapons (all along different edges) and
the secondary flamer (flame origin is walked until not on the vehicle).

Since projectiles now must travel farther to reach the front of the
vehicle, some shorter ranged ammos are adjusted to compensate.

The hardpoint check `clear_los()` is removed since now all origins are
inside the vehicle's bounds.

Removed redundant call to `display_ammo()` when firing secondary flamer.

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# Explain why it's good for the game

Projectiles originating from the tile in front of a vehicle make it
extremely hard or even impossible to engage targets adjacent to it. With
this change the projectile, and resulting cone of fire, starts where you
would expect it to.
# Testing Photographs and Procedure
<details>
<summary>Screenshots & Videos</summary>

Put screenshots and videos here with an empty line between the
screenshots and the `<details>` tags.

</details>


# Changelog
:cl:
qol: vehicle weapon projectiles start from the weapon
/:cl:

code/_onclick/adjacent.dm

@@ -25,7 +25,7 @@
 	* If you are diagonally adjacent, ensure you can pass through at least one of the mutually adjacent square.
 		* Passing through in this case ignores anything with the throwpass flag, such as tables, racks, and morgue trays.
 */
-/turf/Adjacent(atom/neighbor, atom/target = null)
+/turf/Adjacent(atom/neighbor, atom/target = null, list/ignore_list)
 	var/turf/T0 = get_turf(neighbor)
 	if(T0 == src)
 		return TRUE
@@ -34,22 +34,22 @@
 
 	if(T0.x == x || T0.y == y)
 		// Check for border blockages
-		return T0.ClickCross(get_dir(T0,src), border_only = 1) && src.ClickCross(get_dir(src,T0), border_only = 1, target_atom = target)
+		return T0.ClickCross(get_dir(T0,src), border_only = 1, ignore_list = ignore_list) && src.ClickCross(get_dir(src,T0), border_only = 1, target_atom = target, ignore_list = ignore_list)
 
 	// Not orthagonal
 	var/in_dir = get_dir(neighbor,src) // eg. northwest (1+8)
 	var/d1 = in_dir&(in_dir-1) // eg west (1+8)&(8) = 8
 	var/d2 = in_dir - d1 // eg north (1+8) - 8 = 1
 
 	for(var/d in list(d1,d2))
-		if(!T0.ClickCross(d, border_only = 1))
+		if(!T0.ClickCross(d, border_only = 1, ignore_list = ignore_list))
 			continue // could not leave T0 in that direction
 
 		var/turf/T1 = get_step(T0,d)
-		if(!T1 || T1.density || !T1.ClickCross(get_dir(T1,T0)|get_dir(T1,src), border_only = 0))
+		if(!T1 || T1.density || !T1.ClickCross(get_dir(T1,T0)|get_dir(T1,src), border_only = 0, ignore_list = ignore_list))
 			continue // couldn't enter or couldn't leave T1
 
-		if(!src.ClickCross(get_dir(src,T1), border_only = 1, target_atom = target))
+		if(!src.ClickCross(get_dir(src,T1), border_only = 1, target_atom = target, ignore_list = ignore_list))
 			continue // could not enter src
 
 		return TRUE // we don't care about our own density
@@ -131,8 +131,11 @@ Quick adjacency (to turf):
 	This is defined as any dense ON_BORDER object, or any dense object without throwpass.
 	The border_only flag allows you to not objects (for source and destination squares)
 */
-/turf/proc/ClickCross(target_dir, border_only, target_atom = null)
+/turf/proc/ClickCross(target_dir, border_only, target_atom = null, list/ignore_list)
 	for(var/obj/O in src)
+		if(O in ignore_list)
+			continue
+
 		if(!O.density || O == target_atom || O.throwpass)
 			continue // throwpass is used for anything you can click through
 

code/datums/ammo/misc.dm

@@ -51,6 +51,8 @@
 /datum/ammo/flamethrower/tank_flamer
 	flamer_reagent_id = "napalmx"
 
+	max_range = 8
+
 /datum/ammo/flamethrower/sentry_flamer
 	flags_ammo_behavior = AMMO_IGNORE_ARMOR|AMMO_IGNORE_COVER|AMMO_FLAME
 	flamer_reagent_id = "napalmx"
@@ -267,6 +269,9 @@
 	nade_type = /obj/item/explosive/grenade/smokebomb
 	icon_state = "smoke_shell"
 
+/datum/ammo/grenade_container/tank_glauncher
+	max_range = 8
+
 /datum/ammo/hugger_container
 	name = "hugger shell"
 	ping = null

code/datums/ammo/rocket.dm

@@ -144,6 +144,8 @@
 		return
 	return ..()
 
+/datum/ammo/rocket/ap/tank_towlauncher
+	max_range = 8
 
 /datum/ammo/rocket/ltb
 	name = "cannon round"

code/modules/projectiles/projectile.dm

@@ -211,8 +211,8 @@
 
 	if(F && !(projectile_flags & PROJECTILE_SHRAPNEL))
 		permutated |= F //Don't hit the shooter (firer)
-	else if (S && (projectile_flags & PROJECTILE_SHRAPNEL))
-		permutated |= S
+	if (S)
+		permutated |= get_atom_on_turf(S) //Don't hit the originating object
 
 	permutated |= src //Don't try to hit self.
 	shot_from = S
@@ -357,8 +357,14 @@
 	if((speed * world.tick_lag) >= get_dist(current_turf, target_turf))
 		SEND_SIGNAL(src, COMSIG_BULLET_TERMINAL)
 
+
+	var/list/ignore_list
+	var/obj/item/hardpoint/hardpoint = shot_from
+	if(istype(hardpoint))
+		LAZYOR(ignore_list, hardpoint.owner) //if fired from a vehicle, exclude the vehicle's body from the adjacency check
+
 	// Check we can reach the turf at all based on pathed grid
-	if(check_canhit(current_turf, next_turf))
+	if(check_canhit(current_turf, next_turf, ignore_list))
 		return TRUE
 
 	// Actually move
@@ -594,9 +600,9 @@
 	if(SEND_SIGNAL(src, COMSIG_BULLET_POST_HANDLE_MOB, L, .) & COMPONENT_BULLET_PASS_THROUGH)
 		return FALSE
 
-/obj/projectile/proc/check_canhit(turf/current_turf, turf/next_turf)
+/obj/projectile/proc/check_canhit(turf/current_turf, turf/next_turf, list/ignore_list)
 	var/proj_dir = get_dir(current_turf, next_turf)
-	if((proj_dir & (proj_dir - 1)) && !current_turf.Adjacent(next_turf))
+	if((proj_dir & (proj_dir - 1)) && !current_turf.Adjacent(next_turf, ignore_list = ignore_list))
 		ammo.on_hit_turf(current_turf, src)
 		current_turf.bullet_act(src)
 		return TRUE

code/modules/vehicles/apc/apc.dm

@@ -178,7 +178,7 @@ GLOBAL_LIST_EMPTY(command_apc_list)
 	V.add_hardpoint(FPW)
 	FPW.dir = turn(V.dir, 90)
 	FPW.name = "Left "+ initial(FPW.name)
-	FPW.origins = list(2, 0)
+	FPW.origins = list(1, 0)
 	FPW.muzzle_flash_pos = list(
 		"1" = list(-18, 14),
 		"2" = list(18, -42),
@@ -191,7 +191,7 @@ GLOBAL_LIST_EMPTY(command_apc_list)
 	V.add_hardpoint(FPW)
 	FPW.dir = turn(V.dir, -90)
 	FPW.name = "Right "+ initial(FPW.name)
-	FPW.origins = list(-2, 0)
+	FPW.origins = list(-1, 0)
 	FPW.muzzle_flash_pos = list(
 		"1" = list(16, 14),
 		"2" = list(-18, -42),

code/modules/vehicles/hardpoints/hardpoint.dm

@@ -314,45 +314,6 @@
 
 	return data
 
-/// Traces backwards from the gun origin to the vehicle to check for obstacles between the vehicle and the muzzle.
-/obj/item/hardpoint/proc/clear_los()
-	if(origins[1] == 0 && origins[2] == 0) //skipping check for modules we don't need this
-		return TRUE
-
-	var/turf/muzzle_turf = get_origin_turf()
-
-	var/turf/checking_turf = muzzle_turf
-	while(!(owner in checking_turf))
-		// Dense turfs block LoS
-		if(checking_turf.density)
-			return FALSE
-
-		// Ensure that we can pass over all objects in the turf
-		for(var/obj/object in checking_turf)
-			// Since vehicles are multitile the
-			if(object == owner)
-				continue
-
-			// Non-dense objects are irrelevant
-			if(!object.density)
-				continue
-
-			// Make sure we can pass object from all directions
-			if(!HAS_FLAG(object.pass_flags.flags_can_pass_all, PASS_OVER_THROW_ITEM))
-				if(!HAS_FLAG(object.flags_atom, ON_BORDER))
-					return FALSE
-				//If we're behind the object, check the behind pass flags
-				else if(dir == object.dir && !HAS_FLAG(object.pass_flags.flags_can_pass_behind, PASS_OVER_THROW_ITEM))
-					return FALSE
-				//If we're in front, check front pass flags
-				else if(dir == turn(object.dir, 180) && !HAS_FLAG(object.pass_flags.flags_can_pass_front, PASS_OVER_THROW_ITEM))
-					return FALSE
-
-		// Trace back towards the vehicle
-		checking_turf = get_step(checking_turf, turn(dir,180))
-
-	return TRUE
-
 //-----------------------------
 //------INTERACTION PROCS----------
 //-----------------------------
@@ -613,10 +574,6 @@
 		to_chat(user, SPAN_WARNING("<b>The target is not within your firing arc!</b>"))
 		return NONE
 
-	if(!clear_los())
-		to_chat(user, SPAN_WARNING("<b>The muzzle is obstructed!</b>"))
-		return NONE
-
 	return handle_fire(target, user, params)
 
 /// Actually fires the gun, sets up the projectile and fires it.

code/modules/vehicles/hardpoints/hardpoint_ammo/gl_ammo.dm

@@ -4,7 +4,7 @@
 	caliber = "grenade"
 	icon_state = "glauncher_2"
 	w_class = SIZE_LARGE
-	default_ammo = /datum/ammo/grenade_container
+	default_ammo = /datum/ammo/grenade_container/tank_glauncher
 	max_rounds = 10
 	gun_type = /obj/item/hardpoint/secondary/grenade_launcher
 

code/modules/vehicles/hardpoints/hardpoint_ammo/tow_ammo.dm

@@ -5,6 +5,6 @@
 	caliber = "rocket" //correlates to any rocket mags
 	icon_state = "quad_rocket"
 	w_class = SIZE_LARGE
-	default_ammo = /datum/ammo/rocket/ap
+	default_ammo = /datum/ammo/rocket/ap/tank_towlauncher
 	max_rounds = 5
 	gun_type = /obj/item/hardpoint/secondary/towlauncher

code/modules/vehicles/hardpoints/holder/tank_turret.dm

@@ -212,8 +212,3 @@
 		target = L
 
 	return ..()
-
-/obj/item/hardpoint/holder/tank_turret/get_origin_turf()
-	var/origin_turf = ..()
-	origin_turf = get_step(get_step(origin_turf, owner.dir), owner.dir) //this should get us tile in front of tank to prevent grenade being stuck under us.
-	return origin_turf

code/modules/vehicles/hardpoints/primary/arc_sentry.dm

@@ -33,7 +33,6 @@
 	)
 	burst_delay = 2
 	burst_amount = 3
-	projectile_type = /obj/projectile/arc_sentry
 
 	/// Potential targets the turret can shoot at
 	var/list/targets = list()
@@ -97,12 +96,6 @@
 
 	return try_fire(target, null, params)
 
-
-/obj/item/hardpoint/primary/arc_sentry/generate_bullet(mob/user, turf/origin_turf)
-	var/obj/projectile/arc_sentry/made_projectile = ..()
-	made_projectile.permutated += owner
-	return made_projectile
-
 /obj/item/hardpoint/primary/arc_sentry/start_fire(datum/source, atom/object, turf/location, control, params)
 	if(QDELETED(object))
 		return
@@ -199,31 +192,3 @@
 		return FALSE
 
 	return ..()
-
-/obj/projectile/arc_sentry/Initialize(mapload, datum/cause_data/cause_data)
-	. = ..()
-	RegisterSignal(src, COMSIG_BULLET_POST_HANDLE_OBJ, PROC_REF(check_passthrough))
-
-/obj/projectile/arc_sentry/check_canhit(turf/current_turf, turf/next_turf)
-	var/proj_dir = get_dir(current_turf, next_turf)
-	var/obj/item/hardpoint/arc_sentry = shot_from
-	if(!(arc_sentry.owner in current_turf) && !(arc_sentry.owner in next_turf) && (proj_dir & (proj_dir - 1)) && !current_turf.Adjacent(next_turf))
-		ammo.on_hit_turf(current_turf, src)
-		current_turf.bullet_act(src)
-		return TRUE
-
-	// Check for hits that would occur when moving to turf, such as a blocking cade
-	if(scan_a_turf(next_turf, proj_dir))
-		return TRUE
-
-	return FALSE
-
-/obj/projectile/arc_sentry/proc/check_passthrough(datum/source, obj/hit_obj, bool)
-	SIGNAL_HANDLER
-
-	if(!istype(shot_from, /obj/item/hardpoint))
-		return
-
-	var/obj/item/hardpoint/sentry = shot_from
-	if(sentry.owner == hit_obj)
-		return COMPONENT_BULLET_PASS_THROUGH

code/modules/vehicles/hardpoints/primary/autocannon.dm

@@ -10,8 +10,6 @@
 	health = 500
 	firing_arc = 60
 
-	origins = list(0, -3)
-
 	ammo = new /obj/item/ammo_magazine/hardpoint/ace_autocannon
 	max_clips = 2
 

code/modules/vehicles/hardpoints/primary/dual_cannon.dm

@@ -14,7 +14,7 @@
 	health = 500
 	firing_arc = 60
 
-	origins = list(0, -2)
+	origins = list(0, 1)
 
 	ammo = new /obj/item/ammo_magazine/hardpoint/boyars_dualcannon
 	max_clips = 2

code/modules/vehicles/hardpoints/primary/flamer.dm

@@ -10,8 +10,6 @@
 	health = 400
 	firing_arc = 90
 
-	origins = list(0, -3)
-
 	ammo = new /obj/item/ammo_magazine/hardpoint/primary_flamer
 	max_clips = 1
 
@@ -33,9 +31,8 @@
 		BULLET_TRAIT_ENTRY(/datum/element/bullet_trait_iff)
 	))
 
-/obj/item/hardpoint/primary/flamer/try_fire(target, user, params)
-	var/turf/origin_turf = get_origin_turf()
-	if(origin_turf == get_turf(target))
+/obj/item/hardpoint/primary/flamer/try_fire(atom/target, mob/living/user, params)
+	if(get_turf(target) in owner.locs)
 		to_chat(user, SPAN_WARNING("The target is too close."))
 		return NONE
 

code/modules/vehicles/hardpoints/primary/ltb.dm

@@ -10,8 +10,6 @@
 	health = 500
 	firing_arc = 60
 
-	origins = list(0, -3)
-
 	ammo = new /obj/item/ammo_magazine/hardpoint/ltb_cannon
 	max_clips = 3
 

code/modules/vehicles/hardpoints/primary/minigun.dm

@@ -9,8 +9,6 @@
 	health = 350
 	firing_arc = 90
 
-	origins = list(0, -3)
-
 	ammo = new /obj/item/ammo_magazine/hardpoint/ltaaap_minigun
 	max_clips = 1
 

code/modules/vehicles/hardpoints/secondary/cupola.dm

@@ -10,8 +10,6 @@
 	health = 350
 	firing_arc = 120
 
-	origins = list(0, -2)
-
 	ammo = new /obj/item/ammo_magazine/hardpoint/m56_cupola
 	max_clips = 1
 

code/modules/vehicles/hardpoints/secondary/flamer.dm

@@ -10,8 +10,6 @@
 	health = 300
 	firing_arc = 120
 
-	origins = list(0, -2)
-
 	ammo = new /obj/item/ammo_magazine/hardpoint/secondary_flamer
 	max_clips = 1
 
@@ -29,14 +27,28 @@
 	scatter = 6
 	fire_delay = 3.0 SECONDS
 
+/obj/item/hardpoint/secondary/small_flamer/try_fire(atom/target, mob/living/user, params)
+	if(get_turf(target) in owner.locs)
+		to_chat(user, SPAN_WARNING("The target is too close."))
+		return NONE
+
+	return ..()
+
 /obj/item/hardpoint/secondary/small_flamer/handle_fire(atom/target, mob/living/user, params)
-	var/turf/origin_turf = get_origin_turf()
+	//step forward along path so flame starts outside hull
+	var/list/turfs = get_line(get_origin_turf(), get_turf(target))
+	var/turf/origin_turf
+	for(var/turf/turf as anything in turfs)
+		if(turf in owner.locs)
+			continue
+		origin_turf = turf
+		break
 
 	var/distance = get_dist(origin_turf, get_turf(target))
 	var/fire_amount = min(ammo.current_rounds, distance+1, max_range)
 	ammo.current_rounds -= fire_amount
 
-	new /obj/flamer_fire(origin_turf, create_cause_data(initial(name), user), null, fire_amount, null, FLAMESHAPE_LINE, target, CALLBACK(src, PROC_REF(display_ammo), user))
+	new /obj/flamer_fire(origin_turf, create_cause_data(initial(name), user), null, fire_amount, null, FLAMESHAPE_LINE, target)
 
 	play_firing_sounds()
 

code/modules/vehicles/hardpoints/secondary/frontal_cannon.dm

@@ -13,7 +13,7 @@
 	health = 350
 	firing_arc = 120
 
-	origins = list(0, -2)
+	origins = list(0, -1)
 
 	ammo = new /obj/item/ammo_magazine/hardpoint/m56_cupola/frontal_cannon
 	max_clips = 1