Hi ulrich, As Paul said, OpenGL doesn't have any convention. It's just a "common usage" that tell us we should use right-handed. However, I agree the number of proposed options could be reduced (I just fear that it may become less explicit... or not?).
Your reflexion make me think we should merge read and write options. That way, we may have the two options you mentionned, and writing would the do the opposite operation. We thus keep write(read(A)) == A. Is that okay for you? Sukender PVLE - Lightweight cross-platform game engine - http://pvle.sourceforge.net/ ----- "Ulrich Hertlein" <u.hertl...@sandbox.de> a écrit : > Hi all, > > On 30/12/09 11:35 AM, Sukender wrote: > > - Have plugins do NO rotation by default (reading and writing) when > the format doesn't > have coordinate system information (that is to say all but FBX and > maybe FLT). > > - Have plugins read and apply coordinate system information if > available by default when reading. > > - Have optionnal READING options: > > - readXup, readYup, readZup to suppose model is X, Y or Z-up > (overrides format's > coordinate system information) > > - readLeftHanded, readRightHanded (similar setting) > > - When in conflict (two options defined), use the latest one > > - Have optionnal WRITING options: > > - writeXup, writeYup, writeZup, writeLeftHanded, writeRightHanded > (which should almost > never be supported, in my opinion) > > - Let plugings optionnally support these options prefixed with their > name and "_". For > instance "3ds_readYup" would assume ONLY ".3ds" files are Y-up. These > would take > precedence over the general settings. > > - Also support "pluginName_read/writeAutoUp" and > "pluginName_read/writeAutoHanded", > which would specifically deactivate a global setting for a given > plugin. For instance, > > Do we really want all those options? At the moment we only have: > - rotate around X-axis (for Y-up to Z-up conversion) and > - convert left- to right-hand CS > > While I agree that plugins could leave the orientation alone I still > think that they > should do the conversion to a right-handed coordinate system by > default, because the > default OpenGL face-winding is right handed. > > Additionally, how would the applied transformation be transmitted to > the writer? If this > were to be stored with the loaded node then it could be automatically > be undone by the > writer. Another possibility might be to just create a transformation > node above the > unmodified model. The transformation node could do all the necessary > scaling/rotation > (and FrontFace); this could simply be ignored when writing. The > downside of this is that > it doesn't integrate nicely and might be a performance penalty. > > Cheers, > /ulrich > _______________________________________________ > osg-users mailing list > osg-users@lists.openscenegraph.org > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
