Interactive 3D Graphics Applications for Tcl

This paper presents an approach to integrate interactive real-time 3D graphics into the scripting language Tcl. 3D graphics libraries are typically implemented in system programming languages such as C or C++ in order to be type safe and fast. We have developed a technique that analyzes the C++ application programming interface of such a library and maps it to appropriate scripting commands and structures. As 3D graphics library, we apply the Virtual Rendering System, an object-oriented library that supports 3D modeling, interaction, and animation. The mapped API represents a complete and powerful development tool for interactive, animated 3D graphics applications. The mapping technique takes advantage of the weak typing and dynamic features of the scripting language, preserves all usability-critical features of the C++ API, and has no impact on performance so that even real-time 3D applications can be developed. The mapping technique can be applied in general to all kinds of C++ APIs and automated. It also gathers reflection information of the API classes and supports interactive management of API objects. Consequently, interactive development environments can be built easily based on this information. We illustrate the approach by several examples of 3D graphics applications.