ARP NPCs API simplified.

ARP_Core_NPCs.sma

// ARP_Core.sma

// Handler for NPC registration API call
public _ARP_RegisterNpc(plugin, params) {
  new ent = create_entity("info_target")
  entity_set_string(ent, EV_SZ_classname, NPC_CLASSNAME) // "arp_npc"
  entity_set_string(ent, EV_SZ_model, NPC_MODEL) // "711clerk"

  // Store the registering plugin on the NPC so we can notify it of events later
  entity_set_int(ent, EV_INT_iuser3, plugin)

  // ... set other parameters passed from plugin
}

// Called on every server frame for every client
public client_PreThink(id) {
  new ent = looking_at_npc(id)

  // Check if the user is looking at an entity and holding down the "Use" button
  if (ent && entity_get_int(id,EV_INT_button) & IN_USE) {
    // Get the plugin from the entity which we registered earlier
    new plugin = entity_get_int(ent, EV_INT_iuser3)
    // Send a callback to the plugin notifying it that the NPC was "used" (chatted with)
    notify_plugin_of_use(plugin, ent)
  }
}