Planning for Non-player Characters Using HTN and Visual Perception

Abstract

Serious games are designed and built for an educational primary purpose other than pure entertainment. While team planning and cooperation is essential for the success of the goal of the game, it also plays an essential role in enhancing the believability of the game. Our serious game is in the domain of emergency management, fire fighters in accidents situations. Two contributions are presented in this paper, firstly, enhanced visual perception system that mimic center of attention in humans eye for each NPC along with a short-term memory (working memory) so that NPCs will have access to only limited information and have to build their plans and make their decisions based on what they can perceive from their surrounding environment. Secondly, a distributed HTN planning approach is implemented based on SHOP for the domain of our serious game. Five modules were developed in this part, Controller, World Model, Domain, Interface and HTN Planner. There is two level of planning, team level plans and individual level plans. Plans are generated online based on the information gathered from the visual perception system and stored in the working memory. Our experiment shows The effectiveness of the proposed approach to generate plans.