Thanks J-S for pointing out that leaf tiles have no PagedLOD nodes. That changes things a bit; don't know how I missed it. Since then I've tried to use VPB to output a good sample database. Right now I'm stuck on a few more problems. Hopefully there are solutions for these troubles that I just haven't found yet. If anyone knows any solutions or workarounds to these issues I'd be happy to hear them.
1. Units. My database defaults to being built in degrees. I would prefer meters, which can be achieved using the --range option. (Actually, --range appears to be necessary to keep the database from being completely square, which is incorrect anyplace other than on the equator.) Once I've used --range on one item, it must be used on everything to get all my sources in the same coordinate system. This is unwieldy when there are a lot of source images and/or DEMs. Since all my images and DEMs contain geographic info, it would probably be better to have some option that just lets you specify the units for the final database, and some way to squash the database appropriately depending on the latitude. 2. My main GEOTiff contains geographic info, but fails to reproject if any of my DEMs do not use the --range option. This appears to be a GDAL error, but I don't understand it well enough to fix it yet: ERROR 1: Unable to compute a transformation between pixel/line and georeferenced coordinates for 37N_123Wx39N_121W.tif. There is no affine transformation and no GCPs. Failed to reproject 37N_123Wx39N_121W.tif 3. --range values for images can be entered in either order, min-max or max-min. For DEMs, order matters. This is odd, but is probably very fixable. 5. I'd like to be able to specify a minimum number of levels to build for the whole database, and then build more levels where there is high-res imagery. So far I can't find any way to do this. Without this I'd be building a huge number of tiles that don't have high-enough-res elevation or image data to justify their existence. 6. Creator loads up my .flt files in bad, indescribable, uneditable ways (probably due to my horribly outdated version of Creator). 7. I need the output image files to be separate from the terrain files when editing .flt. I don't see a way to build tiles with separate image files, but I think I've seen a code snippet somewhere for extracting images. Other options are welcome. 8. I still need to work out the reasons for the big file size differences between my output .ive files and the .flt files I convert them too. Converting back to .osg I noticed huge lists of Geodes each containing one triangle. Maybe I can do some tri-stripifying when converting back from .flt to .ive. -- Terry Welsh / mogumbo 'at' gmail.com www.reallyslick.com / www.mogumbo.com > > Message: 4 > Date: Thu, 01 Apr 2010 17:20:04 -0400 > From: Jean-S?bastien Guay <jean-sebastien.g...@cm-labs.com> > To: OpenSceneGraph Users <osg-users@lists.openscenegraph.org> > Subject: Re: [osg-users] looking for a terrain database building > Message-ID: <4bb50e04.60...@cm-labs.com> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Hi Terry, > >> Hi J-S. When you convert a file to .flt and then back to .ive, your >> PagedLOD nodes are lost. > > I meant converting the leaf tiles. Unless I'm mistaken (it's been a > while since I analyzed the structure so I might remember wrong), in a > VPB database, you have a master .ive file, which has PagedLOD nodes that > refer to other .ive files, which might have other PagedLODs, etc. > Eventually you have geometry in .ive files that have no PagedLODs. You > could convert these to flt, edit the geometry, and reconvert. But it > does mean that each LOD of each tile is in a separate file, so it's a > bit of a pain to edit all LODs of a certain region to match (you have to > convert and edit as many files as you have levels, separately). > >> The new .ive file is >> also 50X larger than the original and missing its textures, but those >> problems are probably solvable. > > The 50x larger is weird, but the textures you just have to convert to > .osg with -O OutputTextureFiles to recover them (convert to .osg and to > .flt then delete the .osg file). I don't know if the flt output plugin > has a similar option, I know about that one for the .osg output plugin > so I've always used that. > >> No, I need tiles to be in separate files. > > I understand that, but what I meant is that the VPB structure is > hierarchical. You have the first LOD (lowest-res) with the whole terrain > at very low resolution, then two or four tiles at higher resolution, > then each of those splits into four again, etc. So level i has 4^i tiles > in general for square terrain. > >>> If you want to make all tiles at all LODs the same size, then I guess >>> that could be added as an option in VPB. But then what would you replace >>> PagedLOD with? ProxyNode? >> >> I don't understand what you mean here. > > I mean if you want VPB to build non-quadtree LOD structures. i.e. each > LOD you have the same number of tiles, and each tile fits the same > world-space bound. > > J-S _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
