HLA Proxy: Towards Connecting Agents to Virtual Environments by Means of High Level Architecture (HLA)

Coupling virtual environments (e.g. game engines like Source Engine or Unreal Engine 3) with agent reasoning systems (ARS) is often used in the multi-agent systems (MAS) research field. However, externally connecting ARS or MAS to environments almost always requires individual approach for every coupling. Therefore, we recognize the need for a common method of access, without the need to implement a network stack, network protocol or data management. In this paper, we present our new project HLA Proxy utilizing the High Level Architecture (HLA) standard (IEEE 1516-2010) for interconnecting simulations and simulators. We created a C++ prototype middleware providing universal and transparent access to the HLA infrastructure for not HLA-capable applications (i.e. ARS, MAS, visualization tools etc.), thus allowing cross-platform, distributed connection to environments and between environments. Our work is aimed at being directly integrated into the environment (i.e. engine) and application via dynamic linkage. Here, we present our architecture and our proof-of-concept integration into CryENGINE 3 (used for the Crysis game) and Source Engine (used for the HalfLife 2 game) running on Windows XP 32bit and Windows 7 64bit platforms. We also implemented a 64bit Linux console application utilizing HLA Proxy to connect to both engines capable to send console commands and receive environment updates.