fix 6x69 command 02 checks

src/CommandFormats.hh

@@ -4581,7 +4581,7 @@ struct G_CreateTelepipe_6x68 {
 
 struct G_NPCControl_6x69 {
   G_UnusedHeader header;
-  le_uint16_t param1; // Commands 0/3: state; commands 1/2: npc_entity_id
+  le_uint16_t param1; // Commands 0/3: state; command 1: npc_entity_id; command 2: unknown
   le_uint16_t param2; // Commands 0/3: npc_entity_id; commands 1/2: unused
   le_uint16_t command = 0; // 0 = create follower NPC, 1 = stop acting, 2 = start acting, 3 = create attacker NPC
   le_uint16_t param3; // Commands 0/3: npc_template_index; commands 1/2: unused

src/ReceiveSubcommands.cc

@@ -1028,20 +1028,21 @@ static void on_npc_control(shared_ptr<Client> c, uint8_t command, uint8_t flag,
     throw runtime_error("cannot create or modify NPC in the lobby");
   }
 
-  uint16_t npc_entity_id = 0xFFFF;
+  int32_t npc_entity_id = -1;
   switch (cmd.command) {
     case 0:
     case 3:
       npc_entity_id = cmd.param2;
       break;
     case 1:
-    case 2:
       npc_entity_id = cmd.param1;
       break;
+    case 2:
+      break;
     default:
       throw runtime_error("invalid 6x69 command");
   }
-  if ((npc_entity_id < 4) && l->clients[npc_entity_id]) {
+  if ((npc_entity_id >= 0) && (npc_entity_id < 4) && l->clients[npc_entity_id]) {
     throw runtime_error("cannot create or modify NPC in existing player slot");
   }