Code Safe spawn location for Mobs

Hi,

It searches for a suitable location in a circular area around the original spawn location by incrementally increasing the distance from the original point and checking different angles. It then checks if there's a wall or obstruction within safeDistance units from the potential new location.

 

Index: /main/L2GoldClassic/java/gold/lineage2/gameserver/model/Spawn.java
===================================================================
--- /main/L2GoldClassic/java/gold/lineage2/gameserver/model/Spawn.java	(revision 25)
+++ /main/L2GoldClassic/java/gold/lineage2/gameserver/model/Spawn.java	(revision 26)
@@ -29,4 +29,5 @@
 import gold.lineage2.gameserver.data.xml.NpcData;
 import gold.lineage2.gameserver.geoengine.GeoEngine;
+import gold.lineage2.gameserver.geoengine.geodata.GeoStructure;
 import gold.lineage2.gameserver.instancemanager.DropManager;
 import gold.lineage2.gameserver.instancemanager.WalkingManager;
@@ -407,13 +408,24 @@
 		}
 		
-		// Correct Z of monsters. Do not correct Z of flying NPCs.
-		if (npc.isMonster() && !npc.isFlying())
-		{
-			final int geoZ = GeoEngine.getInstance().getHeight(newlocx, newlocy, newlocz);
-			// Do not correct Z distances greater than 300.
-			if (Util.calculateDistance(newlocx, newlocy, newlocz, newlocx, newlocy, geoZ, true, false) < 300)
+		if (npc.isMonster())
+		{
+			// Correct Z of monsters. Do not correct Z of flying NPCs.
+			if (!npc.isFlying())
 			{
-				newlocz = geoZ;
+				final int geoZ = GeoEngine.getInstance().getHeight(newlocx, newlocy, newlocz);
+				// Do not correct Z distances greater than 300.
+				if (Util.calculateDistance(newlocx, newlocy, newlocz, newlocx, newlocy, geoZ, true, false) < 300)
+				{
+					newlocz = geoZ;
+				}
 			}
+			
+			// Find a safe spawn location
+			Location safeSpawnLocation = findSafeSpawnLocation(newlocx, newlocy, newlocz, 200);
+			
+			// Update the spawn location
+			newlocx = safeSpawnLocation.getX();
+			newlocy = safeSpawnLocation.getY();
+			newlocz = safeSpawnLocation.getZ();
 		}
 		
@@ -475,4 +487,53 @@
 		
 		return npc;
+	}
+	
+	/**
+	 * Finds a safe spawn location at least 'safeDistance' units away from the nearest wall.
+	 *
+	 * @param x the original x-coordinate of the spawn location
+	 * @param y the original y-coordinate of the spawn location
+	 * @param z the original z-coordinate of the spawn location
+	 * @param safeDistance the minimum distance from the nearest wall for the new spawn location
+	 * @return a new Location object containing the safe spawn location
+	 */
+	private Location findSafeSpawnLocation(int x, int y, int z, int safeDistance)
+	{
+	    Location newLocation = new Location(x, y, z);
+	    GeoEngine geoEngine = GeoEngine.getInstance();
+
+	    // Search for a safe spawn location in a circular area around the original spawn location
+	    for (int radius = safeDistance; radius < 5000; radius += safeDistance)
+	    {
+	        for (int angle = 0; angle < 360; angle += 45)
+	        {
+	            int newX = x + (int) (radius * Math.cos(Math.toRadians(angle)));
+	            int newY = y + (int) (radius * Math.sin(Math.toRadians(angle)));
+	            int newZ = geoEngine.getHeight(newX, newY, z);
+
+	            boolean canSeeWall = false;
+	            for (int checkDistance = 0; checkDistance <= safeDistance; checkDistance += GeoStructure.CELL_IGNORE_HEIGHT)
+	            {
+	                int checkX = newX + (int) (checkDistance * Math.cos(Math.toRadians(angle)));
+	                int checkY = newY + (int) (checkDistance * Math.sin(Math.toRadians(angle)));
+	                int checkZ = geoEngine.getHeight(checkX, checkY, newZ);
+
+	                if (geoEngine.hasGeoPos(checkX, checkY) && !geoEngine.canMoveToTarget(newX, newY, newZ, checkX, checkY, checkZ, null))
+	                {
+	                    canSeeWall = true;
+	                    break;
+	                }
+	            }
+
+	            if (!canSeeWall)
+	            {
+	                newLocation.setXYZ(newX, newY, newZ);
+	                return newLocation;
+	            }
+	        }
+	    }
+
+	    LOGGER.warning("Could not find a safe spawn location for NPC " + _template.getId() + ". Using original location.");
+	    return newLocation;
 	}