Exercise can improve health and well-being. With this in mind, immersive virtual reality (VR) games are being developed to promote physical activity, and are generally evaluated through user studies. However, building such applications is time consuming and expensive. This paper introduces VR-Rides, an object-oriented application framework focused on the development of experiment-oriented VR exergames. Following the modular programming pattern, this framework facilitates the integration of different hardware (such as VR devices, sensors, and physical activity devices) within immersive VR experiences that overlay game narratives on Google Street View panoramas. Combining software engineering and interaction patterns, modules of VR-Rides can be easily added and managed in the Unity game engine. We evaluate the code efficiency and development effort across our VR exergames developed using VR-Rides. The reliability, maintainability, and usability of our framework are also demonstrated via code metrics analysis and user studies. The results show that investing in a systematic approach to reusing code and design can be a worthwhile effort for researchers beyond software engineering.
K E Y W O R D Scode reuse, exergame, immersive virtual reality, object-oriented application framework, reusable component, Unity
INTRODUCTIONVirtual reality (VR) software applications are useful tools for human-computer interaction (HCI) studies that require users to be immersed in a controlled environment. There are an increasing number of freely available software tools, plug-ins, programming libraries, and packages that employ recent advances in VR for use by the HCI research community. One such example is VR exercise video games (exergames), with different VR exergames used in physical education classes, 1,2 physical health in older adults, 3,4 and physical rehabilitation and therapy. 5,6 These applications are expected to be employed, integrated and improved by researchers and developers in their HCI projects, thus reducing the time, effort, and cost for creating customized applications. But the commercial VR systems, generally games, used are not systematically engineered to be adapted by researchers or to run research studies. For example, VR systems and games focus primarily on enhancing the immersion and enjoyment of user wearing the head-mounted display (HMD), which ignores the collaboration of non-HMD user. In order to study the interaction in collaborative VR, Gugenheimer et al 7 built a system with VR platform, projectors, gamepad, and Softw: Pract Exper. 2020;50:1305-1324.wileyonlinelibrary.com/journal/spe
