GUI / Open-GL

Georg Mischler wrote:

Lars O. Grobe wrote:

Why not continuing one of the existing projects?
   
Most existing projects have one or several disadvantages:
- platform specific
- limited scope of functionality
- obsolete technology (eg. tcl)
- not available for free

for those interested some thoughts on Open-GL:

tcl is used in rshow for the GUI part. Tcl is surely slightly a little dusted, at the time it was one of the free GUIs running on UNIX and Windows. And it still compiles, so why should I go porting it to a new lib ?

IMHO, more relevant for daily work is the way Radiance geometry is fed to Open-GL by the core rendering engine (written in ANSI-C in rshow):
Rshow is based on my experience that being close to the hardware and its Open-GL calls is being close to happiness. If you know the concept of the Open-GL pipeline and your data structure, you know how to speed things up. That worked pretty excellent on Fraunhofer's SGI VGX a dozen years ago. And it saved me substantial megabytes in the current rshow when I got rid of the more general concept of display lists and fed 3- and 4 sided polygons directly to the pipeline. While the docs on the structure of current ATI graphic cards are not as good as on the VGX, programming on the "bare metal" offers still the advantage of knowing what you're doing. And for merging rholo/Open-gl-texture that seems a good thing, as shown by other people's experience.
In the other hand: The reason for using 3d libraries is that the may have effective ways of dealing with 3d objects on a higher level. Culling and level-of-detail are essential key features for handling large data sets. As an example, the way high-glass CAD programs handle complex geometry with 30fps on an ATI X1 while zooming in on a small detail is impressive. But they spent a long time building their data structures when the object loads initially from disk and they are RAM intensive.

Higher libraries, like Java 3D classes, are interesting if they handle at least one of the above aspects well.

-Peter

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