Fix joining netgames not loading up waypoints correctly.

Mobjs get deleted and loaded from net save. The mobjs in the waypoints need to load into the correct waypoints again.
This doesn't save/load the entire waypoints, so they still cannot be edited/added/removed mid-game.

src/k_waypoint.c

@@ -318,6 +318,11 @@ size_t K_GetWaypointHeapIndex(waypoint_t *waypoint)
 	return waypointindex;
 }
 
+size_t K_GetNumWaypoints(void)
+{
+	return numwaypoints;
+}
+
 /*--------------------------------------------------
 	waypoint_t *K_GetWaypointFromIndex(size_t waypointindex)
 
@@ -1478,7 +1483,6 @@ static waypoint_t *K_MakeWaypoint(mobj_t *const mobj)
 	I_Assert(waypointcap != NULL); // No waypoint mobjs in map load
 	I_Assert(numwaypoints < numwaypointmobjs); // waypoint array reached max capacity
 
-	// numwaypoints is incremented later in K_SetupWaypoint
 	madewaypoint = &waypointheap[numwaypoints];
 	numwaypoints++;
 

src/k_waypoint.h

@@ -287,6 +287,16 @@ waypoint_t *K_SearchWaypointHeapForMobj(mobj_t * const mobj);
 --------------------------------------------------*/
 size_t K_GetWaypointHeapIndex(waypoint_t *waypoint);
 
+/*--------------------------------------------------
+	size_t K_GetNumWaypoints(void)
+
+		Returns the number of waypoints that are in the heap.
+		Intended for Net Archiving/Unarchiving
+
+	Return:-
+		The number of waypoints in the heap
+--------------------------------------------------*/
+size_t K_GetNumWaypoints(void);
 
 /*--------------------------------------------------
 	waypoint_t *K_GetWaypointFromIndex(size_t waypointindex)

src/p_saveg.c

@@ -49,6 +49,7 @@ UINT8 *save_p;
 #define ARCHIVEBLOCK_POBJS    0x7F928546
 #define ARCHIVEBLOCK_THINKERS 0x7F37037C
 #define ARCHIVEBLOCK_SPECIALS 0x7F228378
+#define ARCHIVEBLOCK_WAYPOINTS 0x7F46498F
 
 // Note: This cannot be bigger
 // than an UINT16
@@ -1908,6 +1909,49 @@ static void P_NetArchiveThinkers(void)
 	WRITEUINT8(save_p, tc_end);
 }
 
+static void P_NetArchiveWaypoints(void)
+{
+	waypoint_t *waypoint;
+	size_t i;
+	size_t numWaypoints = K_GetNumWaypoints();
+
+	WRITEUINT32(save_p, ARCHIVEBLOCK_WAYPOINTS);
+	WRITEUINT32(save_p, numWaypoints);
+
+	for (i = 0U; i < numWaypoints; i++) {
+		waypoint = K_GetWaypointFromIndex(i);
+
+		// The only thing we save for each waypoint is the mobj.
+		// Waypoints should NEVER be completely created or destroyed mid-race as a result of this
+		WRITEUINT32(save_p, waypoint->mobj->mobjnum);
+	}
+}
+
+static void P_NetUnArchiveWaypoints(void)
+{
+	if (READUINT32(save_p) != ARCHIVEBLOCK_WAYPOINTS)
+		I_Error("Bad $$$.sav at archive block Waypoints!");
+	else {
+		UINT32 numArchiveWaypoints = READUINT32(save_p);
+		size_t numSpawnedWaypoints = K_GetNumWaypoints();
+
+		if (numArchiveWaypoints != numSpawnedWaypoints) {
+			I_Error("Bad $$$.sav: More saved waypoints than created!");
+		} else {
+			waypoint_t *waypoint;
+			UINT32 i;
+			UINT32 temp;
+			for (i = 0U; i < numArchiveWaypoints; i++) {
+				waypoint = K_GetWaypointFromIndex(i);
+				temp = READUINT32(save_p);
+				if (!P_SetTarget(&waypoint->mobj, P_FindNewPosition(temp))) {
+					CONS_Debug(DBG_GAMELOGIC, "waypoint mobj not found for %d\n", i);
+				}
+			}
+		}
+	}
+}
+
 // Now save the pointers, tracer and target, but at load time we must
 // relink to this; the savegame contains the old position in the pointer
 // field copyed in the info field temporarily, but finally we just search
@@ -3526,6 +3570,7 @@ void P_SaveNetGame(void)
 #endif
 		P_NetArchiveThinkers();
 		P_NetArchiveSpecials();
+		P_NetArchiveWaypoints();
 	}
 #ifdef HAVE_BLUA
 	LUA_Archive();
@@ -3570,6 +3615,7 @@ boolean P_LoadNetGame(void)
 #endif
 		P_NetUnArchiveThinkers();
 		P_NetUnArchiveSpecials();
+		P_NetUnArchiveWaypoints();
 		P_RelinkPointers();
 		P_FinishMobjs();
 	}