[PD] Gem - EPS parser

IOhannes m zmoelnig zmoelnig at iem.at
Wed Aug 25 18:10:33 CEST 2004

timon botez wrote:
> Scuse my ignorance. Im using the tex-object to build models and as far 
> as I understand, the text object draws polygons right? How about Gem 
> objects to OBJ's? The rest I can handle in Alias wavefront...
probably i have sent this mail to tim already; but i have lost it and 
just for the archives:

the problem is a bit subtle.
openGL is (to a wide extent) vector-based.
Gem is openGL-based.

however, Gem does not handle the vectors (vertices, polygons,...) itself 
(in very special cases it does so). instead, this is done by the 
openGL-server (which is done by the GPU on modern gfx-cards)
e.g, Gem only tells the openGL-server to rotate an "object"; it does not 
do the calculations itself.

openGL is optimized for a one-way connection (meaning: it is fast to 
send something to the openGL-server; but slow to get information back 
from the server); furthermore i don't even know, whether it is possible, 
to get the vector-information before it is passed to the rasterizer (the 
last stage of rendering: make pixels out of abstract polygons)

of course it would be possible to do all the vector-transformations 
within Gem: this would be slow (as it had to be done on the CPU instead 
of the optimized GPU); AND this would mean a *lot* of re-programming of 
things that are already there.

the forthcoming vertex-stuff (a starter is already in the CVS) will 
handle verteces directly in Gem most of the time
an object-exporter will most probably make sense here.


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