A computer graphics teaching environment supporting multiple languages and a standard graphics library raises many issues, three of which are suitable language interfaces for the library, the representation of geometric data, and supporting multi-language program development. This paper considers these three issues when the library is OpenGL, and the languages are Ada and C.

Teaching environments can exploit semantically richer library interfaces to help catch programming errors earlier; this motivates the author to develop a new OpenGL library interface for Ada. Multiple language support is provided mainly by scripts that translate from Ada to C, or from a neutral representation to both Ada and C. The problems raised by these issues are typical, as are the described solutions to them.

Using the virtual reality modeling language (VRML) to represent geometric data is the most interesting response to the three issues. The author adds to the interest by representing VRML data as procedures. VRML is described and motivated, but the procedural representation is not. Readers can supply their own description and motivation (presumably based on procedural modeling [1]), but it would have been even more interesting to know the author’s thinking (particularly because the paper mentions issues related to procedure size that argue against a procedural modeling interpretation).

Brown reports anecdotal evidence gathered over two semesters; the results were mixed, although the analysis is not detailed. The author’s tools are available from a Web page cited in the paper.