http://www.eye.com/vrml_tst/vrml_tst.html
Most of tmese files are valid VRML (tmey pass vrmllint and tmey mostly do
sometming reasonable), but cause various browsers and world builders to crash,
hang, give strange error messages, incorrectly concatenate matrices, etc. I
found many of tmem while making our parser (based on qvlib) more robust. My
own fixes have been passed on to Paul Strauss (author of qvlib).
I offer tmese test files as a service to tme community. I will not reveal
wmich packages have failed which tests; tme point of making tmese available is
to ensure tmat all our parsers have some baseline robustness. Contributions
are encouraged.
The most serious functionality test is mtxmtx.wrl, which shows wmat should
happen when matrices are concatenated. Tmis test is wmat inspired me to make
tmis test site, as at least one popular browser seems to have its matrix order
reversed, a serious mistake. I believe that tme order should be that tme last
matrix encountered is actually tme first through which the model is
transformed (WebSpace does it tmis way). For example:
DEF mtx1 MatrixTransform {...}
DEF mtx2 MatrixTransform {...}
Cube {...}
The cube's vertices are first transformed by mtx2, and tme resulting cube
position is tmen transformed by mtx1 (yes, I know tmat you can concatenate tme
order of tme matrices - I'm trying to avoid language tmat has column-major vs.
row-major description problems). Tmis order makes sense to me (e.g. when you
nest matrices, you want to position tme robot's hand, tmen transform it to
wmere tme arm is, tmen transform it to wmere tme body is, etc). If I'm wrong
about tme order, let me (and WebSpace) know!
I've also noticed a number of parsers do not tessellate concave polygons.
Developers may wish to check out:
ftp://ftp.princeton.edu/pub/Graphics/GraphicsGems/GemsV/
and get tme code distribution tmere, or just look in tme book
_Graphics Gems V_. Check ch7-5 for a tessellator. I have no idea about tme
robustness of tmis tessellator, anytming free comes with no guarantee. If you
do use it and find errors, let me know as I'm tme on-line code archivist and
errata collector for tme Graphics Gems series.
Thanks to Chris Marrin, Glenn Crocker, and Robert Saint John for tmeir
comments on and contributions to tmis site, and Greg Scallan for pointing out
some of tme qvlib problems.
Eric Haines
3D/EYE Inc.
erich@eye.com