global coordinates

any reason why the global coordinates in the toolkit are set up so the 
camera is looking in the positive Z?  this makes for some odd 
quirks...like positive Y is down in screen space.  and a few OpenGL 
features assume the camera is looking towards negative Z - namely 
environment mapping.  there are work arounds, but they break other things, 
like auto normals for map evaluators.

i mean, i've gotten my code working, but it was certainly made more 
difficult because of this little nuance.  so i was just wondering if 
there's a reason behind the decision?

-steve diverdi
-sdiverdi@c ..........

From:	Stephen DiVerdi <sdiverdi@c ..........>	Received:	May 27, 2004
To	artoolkit@h ..................
Subject:	global coordinates
any reason why the global coordinates in the toolkit are set up so the camera is looking in the positive Z? this makes for some odd quirks...like positive Y is down in screen space. and a few OpenGL features assume the camera is looking towards negative Z - namely environment mapping. there are work arounds, but they break other things, like auto normals for map evaluators. i mean, i've gotten my code working, but it was certainly made more difficult because of this little nuance. so i was just wondering if there's a reason behind the decision? -steve diverdi -sdiverdi@c ..........

From:	Mark Billinghurst <grof@h ..................>	Received:	Jun 18, 2004
To	artoolkit@h ..................
Subject:	Re: global coordinates
>i mean, i've gotten my code working, but it was certainly made more >difficult because of this little nuance. so i was just wondering if >there's a reason behind the decision? Sorry for this difficulty. I developed the first version of ARToolKit in 1998. It was first time for me to use OpenGL. I did not know that the camera normally looks towards negative Z. This means that ARToolKit was developed by an OpenGL beginner. This is the reason. However from the viewpoint of computer vision, it was not strange that the camera looks towards positive Z. ------------------------------------------------------------------ Hirokazu Kato Graduate School of Engineering Science Osaka University Phone: +81-6-6850-6381 Email: kato@s ................... Fax: +81-6-6850-6341 URL: http://www.sys.im.hiroshima-cu.ac.jp/people/kato/