[Plib-devel] VRML Loader issues

[Gil C. <g.c...@ca...>]

At 10:12 AM 8/10/00 -0700, you wrote:

>here's my current code:
><http://www.pond.net/~davem/stuff/blender_import/>http://www.pond.net/~davem/stuff/blender_import/ 
>
>
>i just got started with it so you can start over if you want. i was going 
>to use the ssgParser class in ssg. the WRL files in test_wrl.zip come from 
>exporting the blender examples.  they should be useful regardless of your 
>approach

They are - especially as they are in VRML1, not VRML2 as I was 
expecting.  After VRML1->VRML2 conversion, there are syntax problems with 
them immediately - test1.wrl uses a transform node with negative scaling, 
which is illegal but accepted by "good" browsers.  Hmm....

To provide a little background for my involvement, I offered to write a 
lex/yacc parser for the later VRML97 standard.  The plan was to just 
support static geometry and textures - no sound, movies, animations, 
events, scripting, Java etc.  The parser should read any valid VRML97 file 
without barfing, but will only actually populate an SSG scenegraph with 
geometry and textures.

(Chris St. John has a partially complete parser/loader for VRML97 based on 
an ANTLR grammar, but he hasn't finished it yet.  He recently mentioned 
some good "gotchas" which I'll refer to in my work.)

There has also been a call for VRML1 support, as many CAD packages (and 
Blender) export this.  VRML1 is very similar to the Open Inventor file 
format, but it's quite a different language to VRML 97 - IOW, the '97 
parser won't read it.

Since there would currently be a path to get VRML1 into PLIB via a 
VRML1->VRML2 converter and the VRML97 loader, my initial plan was to get 
the VRML2/VRML97 parser done and then come back to VRML1.  With Blender's 
apparent export of VRML1, this might bump VRML1 support up the priority list.

So what do people think - VRML1 or VRML97 first?

Gil

PS. If you're interested VRML2 and VRML97 are basically identical