Collision handling and shadow casting in Virtual-Prismaker.pdf

Collision Handling and Shadow Casting in Virtual-Prismaker Víctor López, Antonio Fernández-Caballero, Pascual González, Francisco Montero José Pascual Molina Regional Development Institute, University of Castilla-La Mancha (Spain) {victor, caballer, pgonzalez, fmontero, jpmolina}@info-ab.uclm.es Abstract. Our research team is developing a computer construction game called Virtual- Prismaker based on the physical game Prismakertm. We have had to deal with all typical and essential features of any realistic 3D modelling and animation environment. A first aim in these kinds of environments is to provide an easy way to manipulate the game pieces. The need to use standard input devices in a natural manner has guided us to limit movement freedom. This imposed limitation allows the pieces to be easily assembled. As we try to achieve a realistic simulation, collision handling and shadow casting are two more problems found up to date. In this paper we comment some lacks of the Java 3DTM application programming interface in this context, and we propose our solutions. Collision handling is faced by using a 3D grid that stores the position of all objects of the virtual playground. Shadow casting is simulated by drawing polygons according to a single light source and the environmental light and using the associated 3D grid position information. Keywords: Virtual reality, Visualization and manipulation of virtual objects, Collision handling, Shadow casting, Educational games. 1. Introduction The creation of software for children is usually linked to the binomy computer games and visual interfaces. Their playing issues and their attractive interfaces make these kinds of tools especially interesting for educational environments. Using computer games provides new characteristics that improve any learning process. According to Sedighian et al [15] computer games supply meaningful learning, goals, success, challenge, cognitive artifact, and association t