thinman@uunet.UU.NET (01/30/91)
We need a new graphics programming language for Virtual Reality. It should be a user-pull effort, not a vendor-push effort. In this article I outline the alternatives with which we will be faced if we don't move now. Sources of fear: PHIGS There is a strong push by the X vendor community to standardize around PHIGS. This is an old architecture and (apparently) meets most of the needs of the high-end CAD market, but doesn't serve other 3D graphics users (i.e. scientific visualization, virtual reality). PHIGS is a data list representation standard only. It does not address putting a complete program into the graphics hardware; it assumes instead a sufficiently fast linkage between hardware and application for pleasant interaction speeds. Sources of fear: PEX The X Window System will soon be updated to include PHIGS support (PHIGS Extensions for X). Like everything in X, PEX is a clumsy poorly-architected kludge. However, it follows the above profile and it will succeed. X already has support for animation and stereo viewing, and if there is enough market interest the big money behind X will pay to have real-time support kludged into PEX. Sources of fear: Renderman Renderman is Pixar's photorealistic rendering system designed around the Reyes rendering algorithm. They wrote it for their cinema special effects work. Renderman is a very nice system for drawing static pictures. With today's Hot Chips, it can be real-time simply by ignoring 99% of its graphics control parameters. But, it is proprietary, and will stay that way. Also, it is merely a graphics library and thus provides only some of what we need. Sources of fear: GL Silicon Graphic's GL is the proprietary control system for SGI's custom graphics platforms. It is oriented around hardware-based polygonal rendering. I don't know how portable it is, but its installed base puts it in the running. Software-based 3D is simple enough that someone will write a GL emulator to achieve software portability for their project. An Australian graphics package called 'VOGLE' claims to be something like this. The above systems are the top contenders in the race for a clumsy and unpleasant Virtual Reality software development environment. Lance Norskog thinman@cup.portal.com