Hi Torben, I have replied on the osg-user list rather than submissions, hope that's ok.
I cant say exactly what Roberts plan for optional layers was / is but I can tell you how I am using them. Optional image layers have their images stored in a separate directory structure from 'normal' layers. For example, when not using optional layers, all meshes and images will be stored in a directory structure such as: root/ earth.ive earth_root_L0_X0_Y0/ earth_subtile_l_X0_Y0/ If you then add another 'normal' layer, no new files or folders are created, the new imagery is just included (by default) in the existing .ive / .osgb files. When you add an optional layer, all the new imagery is stored under a separate directory. In the case of the above example: root/ earth.ive earth_root_L0_X0_Y0/ earth_subtile_l_X0_Y0/ MyOptionalLayer/ earth_L0_X0_Y0_l1.dds etc I am not sure exactly how loading layers is handled by the default Terrain Technique (I am using a custom one) but one big advantage I gain is that it allows me to load optional layers on demand. If all the imagery for a layer is contained in a single .ive / .osgb file, then this must be loaded as one, regardless of wether all the layers are actually being displayed. With the optional layer approach, it is possible to only the load the imagery that is currently being viewed. This is important for my project as our clients can often have a low bandwidth connection to the map server. This enables us to make a large number of layers available without effecting the load time of the base tiles. My standard setup for VPB generated databases is to only have one 'normal' layer with data such as blue marble. This acts as the default layer that is always available. All other imagery layers are added as optional layers. I hope that makes some sense. Cheers, Brad -----Original Message----- From: osg-submissions-boun...@lists.openscenegraph.org [mailto:osg-submissions-boun...@lists.openscenegraph.org] On Behalf Of Torben Dannhauer Sent: Thursday, 1 July 2010 2:46 PM To: osg-submissi...@lists.openscenegraph.org Subject: Re: [osg-submissions] Fix for adding / removing layers / optional layers using VPB Hi Brad and Robert, thanks for your fixes. One question: can you explain me what optional layers are? ;) Thank you! Cheers, Torben ------------------ Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=29568#29568 _______________________________________________ osg-submissions mailing list osg-submissi...@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-submissions-openscenegraph.org DISCLAIMER:--------------------------------------------------------------------------- This e-mail transmission and any documents, files and previous e-mail messages attached to it are private and confidential. They may contain proprietary or copyright material or information that is subject to legal professional privilege. They are for the use of the intended recipient only. Any unauthorised viewing, use, disclosure, copying, alteration, storage or distribution of, or reliance on, this message is strictly prohibited. No part may be reproduced, adapted or transmitted without the written permission of the owner. If you have received this transmission in error, or are not an authorised recipient, please immediately notify the sender by return email, delete this message and all copies from your e-mail system, and destroy any printed copies. Receipt by anyone other than the intended recipient should not be deemed a waiver of any privilege or protection. Thales Australia does not warrant or represent that this e-mail or any documents, files and previous e-mail messages attached are error or virus free. -------------------------------------------------------------------------------------- _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org