fix series of bugs due to improper multi targeting (#6916)

Multiple issues were discovered to be from improper targeting data in multi
tracing back to the addition of multi-lock. This was due to differences in
how targeting works in single/multi and de-sync of this info between server
and client. Collecting accurate targeting data on the server and making sure
that the client will use that data resolves the tracking and sync issues.

Author: notimaginative

code/network/multimsgs.cpp

@@ -3044,14 +3044,13 @@ void process_cargo_hidden_packet( ubyte *data, header *hinfo )
 #define SFPF_TARGET_LOCKED		(1<<5)
 
 // send a packet indicating a secondary weapon was fired
-void send_secondary_fired_packet( ship *shipp, ushort starting_sig, int  /*starting_count*/, int num_fired, int allow_swarm )
+void send_secondary_fired_packet( ship *shipp, ushort starting_sig, tracking_info &tinfo, int num_fired, int allow_swarm )
 {
 	int packet_size, net_player_num;
 	ubyte data[MAX_PACKET_SIZE], sinfo, current_bank;
 	object *objp;
 	ushort target_net_signature;
 	int s_index;
-	ai_info *aip;
 
 	// Assert ( starting_count < UCHAR_MAX );
 
@@ -3064,8 +3063,6 @@ void send_secondary_fired_packet( ship *shipp, ushort starting_sig, int  /*start
 		}
 	}
 
-	aip = &Ai_info[shipp->ai_index];
-
 	current_bank = (ubyte)shipp->weapons.current_secondary_bank;
 	Assert( (current_bank < MAX_SHIP_SECONDARY_BANKS) );
 
@@ -3086,7 +3083,7 @@ void send_secondary_fired_packet( ship *shipp, ushort starting_sig, int  /*start
 		sinfo |= SFPF_DUAL_FIRE;
 	}
 
-	if ( aip->current_target_is_locked ){
+	if ( tinfo.locked ){
 		sinfo |= SFPF_TARGET_LOCKED;
 	}
 
@@ -3095,14 +3092,14 @@ void send_secondary_fired_packet( ship *shipp, ushort starting_sig, int  /*start
 	// add the ship's target and any targeted subsystem
 	target_net_signature = 0;
 	s_index = -1;
-	if ( aip->target_objnum != -1) {
-		target_net_signature = Objects[aip->target_objnum].net_signature;
-		if ( (Objects[aip->target_objnum].type == OBJ_SHIP) && (aip->targeted_subsys != NULL) ) {
-			s_index = ship_get_subsys_index( aip->targeted_subsys );
+	if (tinfo.objnum != -1) {
+		target_net_signature = Objects[tinfo.objnum].net_signature;
+		if ( (Objects[tinfo.objnum].type == OBJ_SHIP) && (tinfo.subsys != nullptr) ) {
+			s_index = ship_get_subsys_index( tinfo.subsys );
 		}
 
-		if ( Objects[aip->target_objnum].type == OBJ_WEAPON ) {
-			Assert(Weapon_info[Weapons[Objects[aip->target_objnum].instance].weapon_info_index].wi_flags[Weapon::Info_Flags::Bomb]);
+		if ( Objects[tinfo.objnum].type == OBJ_WEAPON ) {
+			Assert(Weapon_info[Weapons[Objects[tinfo.objnum].instance].weapon_info_index].wi_flags[Weapon::Info_Flags::Bomb]);
 		}
 
 	}

code/network/multimsgs.h

@@ -30,6 +30,7 @@ class ship_subsys;
 struct log_entry;
 struct beam_fire_info;
 namespace animation { enum class ModelAnimationDirection; }
+struct tracking_info;
 
 // macros for building up packets -- to save on time and typing.  Important to note that local variables
 // must be named correctly
@@ -270,7 +271,7 @@ void send_game_info_packet( void );
 void send_leave_game_packet(short player_id = -1,int kicked_reason = -1,net_player *target = NULL);
 
 // send a packet indicating a secondary weapon was fired
-void send_secondary_fired_packet( ship *shipp, ushort starting_sig, int starting_count, int num_fired, int allow_swarm );
+void send_secondary_fired_packet( ship *shipp, ushort starting_sig, tracking_info &tinfo, int num_fired, int allow_swarm );
 
 // send a packet indicating a countermeasure was fired
 void send_countermeasure_fired_packet( object *objp, int cmeasure_count, int rand_val );

code/ship/ship.cpp

@@ -13836,7 +13836,7 @@ extern void ai_maybe_announce_shockwave_weapon(object *firing_objp, int weapon_i
 //                need to avoid firing when normally called
 int ship_fire_secondary( object *obj, int allow_swarm, bool rollback_shot )
 {
-	int			n, weapon_idx, j, bank, bank_adjusted, starting_bank_count = -1, num_fired;
+	int			n, weapon_idx, j, bank, bank_adjusted, num_fired;
 	ushort		starting_sig = 0;
 	ship			*shipp;
 	ship_weapon *swp;
@@ -13846,6 +13846,7 @@ int ship_fire_secondary( object *obj, int allow_swarm, bool rollback_shot )
 	polymodel	*pm;
 	vec3d		missile_point, pnt, firing_pos;
 	bool has_fired = false;		// Used to determine whether to fire the scripting hook
+	tracking_info tinfo;
 
 	Assert( obj != NULL );
 
@@ -13932,14 +13933,13 @@ int ship_fire_secondary( object *obj, int allow_swarm, bool rollback_shot )
 
 	if ( MULTIPLAYER_MASTER ) {
 		starting_sig = multi_get_next_network_signature( MULTI_SIG_NON_PERMANENT );
-		starting_bank_count = swp->secondary_bank_ammo[bank];
 	}
 
 	if (ship_fire_secondary_detonate(obj, swp)) {
 		// in multiplayer, master sends a secondary fired packet with starting signature of -1 -- indicates
 		// to client code to set the detonate timer to 0.
 		if ( MULTIPLAYER_MASTER ) {
-			send_secondary_fired_packet( shipp, 0, starting_bank_count, 1, allow_swarm );
+			send_secondary_fired_packet( shipp, 0, tinfo, 1, allow_swarm );
 		}
 
 		//	For all banks, if ok to fire a weapon, make it wait a bit.
@@ -14112,10 +14112,6 @@ int ship_fire_secondary( object *obj, int allow_swarm, bool rollback_shot )
 			return 0;		// we can make a quick out here!!!
 		}
 
-		int target_objnum;
-		ship_subsys *target_subsys;
-		int locked;
-
 		if ( obj == Player_obj || ( MULTIPLAYER_MASTER && obj->flags[Object::Object_Flags::Player_ship] ) ) {
 			// use missile lock slots
 			if ( !shipp->missile_locks_firing.empty() ) {
@@ -14132,39 +14128,35 @@ int ship_fire_secondary( object *obj, int allow_swarm, bool rollback_shot )
 				}
 
 				if (lock_data.obj != nullptr) {
-					target_objnum = OBJ_INDEX(lock_data.obj);
-					target_subsys = lock_data.subsys;
-					locked = 1;
+					tinfo.objnum = OBJ_INDEX(lock_data.obj);
+					tinfo.subsys = lock_data.subsys;
+					tinfo.locked = true;
 				} else {
-					target_objnum = -1;
-					target_subsys = nullptr;
-					locked = 0;
+					tinfo.objnum = -1;
+					tinfo.subsys = nullptr;
+					tinfo.locked = false;
 				}
-			} else if (wip->wi_flags[Weapon::Info_Flags::Homing_heat]) {
-				target_objnum = aip->target_objnum;
-				target_subsys = aip->targeted_subsys;
-				locked = aip->current_target_is_locked;
 			} else {
-				target_objnum = -1;
-				target_subsys = nullptr;
-				locked = 0;
+				tinfo.objnum = aip->target_objnum;
+				tinfo.subsys = aip->targeted_subsys;
+				tinfo.locked = aip->current_target_is_locked == 1;
 			}
 		} else if (wip->multi_lock && !aip->ai_missile_locks_firing.empty()) {
-			target_objnum = aip->ai_missile_locks_firing.back().first;
-			target_subsys = aip->ai_missile_locks_firing.back().second;
-			locked = 1;
+			tinfo.objnum = aip->ai_missile_locks_firing.back().first;
+			tinfo.subsys = aip->ai_missile_locks_firing.back().second;
+			tinfo.locked = true;
 			aip->ai_missile_locks_firing.pop_back();
 		} else {
-			target_objnum = aip->target_objnum;
-			target_subsys = aip->targeted_subsys;
-			locked = aip->current_target_is_locked;
+			tinfo.objnum = aip->target_objnum;
+			tinfo.subsys = aip->targeted_subsys;
+			tinfo.locked = aip->current_target_is_locked == 1;
 		}
 
 		num_slots = pm->missile_banks[bank].num_slots;
 		float target_radius = 0.f;
 
-		if (target_objnum >= 0) {
-			target_radius = Objects[target_objnum].radius;
+		if (tinfo.objnum >= 0) {
+			target_radius = Objects[tinfo.objnum].radius;
 		}
 
 		auto launch_curve_data = WeaponLaunchCurveData {
@@ -14286,7 +14278,7 @@ int ship_fire_secondary( object *obj, int allow_swarm, bool rollback_shot )
 
 			// create the weapon -- for multiplayer, the net_signature is assigned inside
 			// of weapon_create
-			weapon_num = weapon_create( &firing_pos, &firing_orient, weapon_idx, OBJ_INDEX(obj), -1, locked, false, 0.f, nullptr, launch_curve_data);
+			weapon_num = weapon_create( &firing_pos, &firing_orient, weapon_idx, OBJ_INDEX(obj), -1, tinfo.locked, false, 0.f, nullptr, launch_curve_data);
 
 			if (weapon_num == -1) {
 				// Weapon most likely failed to fire
@@ -14298,7 +14290,7 @@ int ship_fire_secondary( object *obj, int allow_swarm, bool rollback_shot )
 
 			if (weapon_num >= 0) {
 				weapon_idx = Weapons[Objects[weapon_num].instance].weapon_info_index;
-				weapon_set_tracking_info(weapon_num, OBJ_INDEX(obj), target_objnum, locked, target_subsys);
+				weapon_set_tracking_info(weapon_num, OBJ_INDEX(obj), tinfo);
 				has_fired = true;
 
 				// create the muzzle flash effect
@@ -14362,7 +14354,7 @@ int ship_fire_secondary( object *obj, int allow_swarm, bool rollback_shot )
 		// Cyborg17 - If this is a rollback shot, the server will let the player know within the packet.
 		if ( MULTIPLAYER_MASTER ) {			
 			Assert(starting_sig != 0);
-			send_secondary_fired_packet( shipp, starting_sig, starting_bank_count, num_fired, allow_swarm );			
+			send_secondary_fired_packet( shipp, starting_sig, tinfo, num_fired, allow_swarm );
 		}
 
 		// Handle Player only stuff, including stats and client secondary packets

code/weapon/weapon.h

@@ -938,6 +938,13 @@ extern SCP_vector<int> Player_weapon_precedence;	// Vector of weapon types, prec
 
 #define WEAPON_INDEX(wp)			(int)(wp-Weapons)
 
+typedef struct tracking_info {
+	ship_subsys *subsys;
+	int objnum;
+	bool locked;
+
+	tracking_info() : subsys(nullptr), objnum(-1), locked(false) {}
+} tracking_info;
 
 int weapon_info_lookup(const char *name);
 int weapon_info_get_index(const weapon_info *wip);
@@ -990,6 +997,11 @@ int weapon_create( const vec3d *pos,
 	});
 void weapon_set_tracking_info(int weapon_objnum, int parent_objnum, int target_objnum, int target_is_locked = 0, ship_subsys *target_subsys = NULL);
 
+inline void weapon_set_tracking_info(int weapon_objnum, int parent_objnum, tracking_info &tinfo)
+{
+	weapon_set_tracking_info(weapon_objnum, parent_objnum, tinfo.objnum, tinfo.locked, tinfo.subsys);
+}
+
 // gets the substitution pattern pointer for a given weapon
 // src_turret may be null
 size_t* get_pointer_to_weapon_fire_pattern_index(int weapon_type, int ship_idx, ship_subsys* src_turret);