From fbc10387c84078e5d815da818435efca75c20fd6 Mon Sep 17 00:00:00 2001
From: UbitUmarov <ajlduarte@sapo.pt>
Date: Fri, 16 Jul 2021 01:52:03 +0100
Subject: [PATCH] add a optional limit on number of npcs per scene default = 40

---
 OpenSim/Region/OptionalModules/World/NPC/NPCModule.cs | 10 ++++++++++
 bin/OpenSim.ini.example                               |  5 +++++
 bin/OpenSimDefaults.ini                               |  6 ++++++
 3 files changed, 21 insertions(+)

diff --git a/OpenSim/Region/OptionalModules/World/NPC/NPCModule.cs b/OpenSim/Region/OptionalModules/World/NPC/NPCModule.cs
index e0f5103a53..053e2ecae4 100644
--- a/OpenSim/Region/OptionalModules/World/NPC/NPCModule.cs
+++ b/OpenSim/Region/OptionalModules/World/NPC/NPCModule.cs
@@ -51,6 +51,8 @@ namespace OpenSim.Region.OptionalModules.World.NPC
         private readonly Dictionary<UUID, NPCAvatar> m_avatars = new Dictionary<UUID, NPCAvatar>();
         private NPCOptionsFlags m_NPCOptionFlags;
 
+        private int m_MaxNumberNPCperScene = 40;
+
         public NPCOptionsFlags NPCOptionFlags {get {return m_NPCOptionFlags;}}
 
         public bool Enabled { get; private set; }
@@ -74,6 +76,8 @@ namespace OpenSim.Region.OptionalModules.World.NPC
 
                 if(config.GetBoolean("NoNPCGroup", true))
                     m_NPCOptionFlags |= NPCOptionsFlags.NoNPCGroup;
+
+                m_MaxNumberNPCperScene = config.GetInt("MaxNumberNPCsPerScene", m_MaxNumberNPCperScene);
             }
         }
 
@@ -161,6 +165,12 @@ namespace OpenSim.Region.OptionalModules.World.NPC
                 Vector3 position, UUID agentID, UUID owner, string groupTitle, UUID groupID, bool senseAsAgent, Scene scene,
                 AvatarAppearance appearance)
         {
+            if(m_MaxNumberNPCperScene > 0)
+            {
+                if(scene.GetRootNPCCount() >= m_MaxNumberNPCperScene)
+                    return UUID.Zero;
+            }
+
             NPCAvatar npcAvatar = null;
             string born = DateTime.UtcNow.ToString();
 
diff --git a/bin/OpenSim.ini.example b/bin/OpenSim.ini.example
index 99ae3d246c..1a7ef1f0a2 100644
--- a/bin/OpenSim.ini.example
+++ b/bin/OpenSim.ini.example
@@ -1208,6 +1208,11 @@
     ;# {Enabled} {} {Enable Non Player Character (NPC) facilities} {true false} false
     ; Enabled = false
 
+    ;; max number of NPCs per scene default: 40
+    ;; set to a negative value to allow any number
+    ;; note that a NPC is almost as heavy as a normal avatar, so you should limit them
+    ;; MaxNumberNPCsPerScene = 40
+
     ;; several options to control NPCs creation
 
     ;# {AllowNotOwned} {} {allow NPCs to be created not Owned} {true false} true
diff --git a/bin/OpenSimDefaults.ini b/bin/OpenSimDefaults.ini
index 55bdda9875..fa3335c040 100644
--- a/bin/OpenSimDefaults.ini
+++ b/bin/OpenSimDefaults.ini
@@ -2142,6 +2142,12 @@
 [NPC]
     ;; Enable Non Player Character (NPC) facilities
     Enabled = false
+
+    ;; max number of NPCs per scene default: 40
+    ;; set to a negative value to allow any number
+    ;; note that a NPC is almost as heavy as a normal avatar, so you should limit them
+    ;; MaxNumberNPCsPerScene = 40
+
     ;; several options to control NPCs creation
 
     ;; allow NPCs to be created not Owned {true false} default: true