Thanks a lot for all your positive feedback. Your interest in osgHimmel convinced me to allocate time and continue maintaining the project.
Jordi Torres wrote: > Great job! You may want to add your project to the community projects[1] > section in the new web or/and post a new to the community news section[2]... > :) Yes, I would like that. Can someone provide my openscenegraph account with the required rights or is there a special procedure of adding new content there? Chris Hanson wrote: > Nice work. I'm going to try it out soon, and hopefully I can add it to our > build system shortly. Sounds great. I'll provide any help you need to get this done. gwaldron wrote: > Looks great. Does it work with geocentric terrain? I'm not sure if i understand your question correct. osgHimmel makes no assumptions of the node or terrain type it is used with, except that the provided altitude should be within the atmosphere or is at ground level (for now, i plan to change this). It further needs date, time, longitude, and latitude. For rendering whole planets, the astronomy part of osgHimmel provides basic coordinate transformations which might be useful. However, in its current status any astrophysical sky of osgHimmel is assumed to be seen from within the atmosphere. If not, moon, sun, and probably star positions need to be adjusted for that. The atmosphere model based on Bruneton and Neyret is limited to skies within the atmosphere, though the suggested model itself is capable of extraterrestrial views. For such use cases, osghimmel should provide an extended node in the future. Jean-Sébastien Guay wrote: > In the past I have used osgEphemeris, which supports sky sphere, sun, moon, > stars based on earth latitude/longitude and date/time. It gave OK results but > had a few problems as well. ... Starting on this project, i evaluated various resources before creating a new library from scratch. osgEphemeris seemed unmaintained for several years. Its results are good in terms of correctness of star and planet positions, but lack of convincing image synthesis. osgHimmel features two astronomy calculations: One as reference impl. based on Meeus book, the second based on simpler models with fewer math. Further, osgHimmel provides correct star color, apparent magnitudes, correct lunar orientation and more. Jean-Sébastien Guay wrote: > Just out of curiosity, how flexible is your library? For example, a long time > ago I had to develop a lunar rover simulator, and I was able to easily use > osgEphemeris' night-time sky (replacing the moon by a larger Earth, of > course, and I didn't mind about exact positions of the stars ) to make the > lunar sky. ... Is something like this easy with your library? Great work! If you are willing to neglect minor errors in star positions, you can create a sky just showing stars and background imagery. The problem however would be to provide an astronomically correct position taking lunar motion into account. Perhaps the easiest way is to take the earth at a specific date/time, calculate the lunar position, pick long and lat based on an earth reference system. osgHimmel probably provides most of this, but some interfaces and transformations have to be adjusted. This is a good use case to generalize the sky positioning more. If you are fine with convincing stars and recognizable star constellations despite correct positioning for the moon, just provide arbitrary longitude and latitude and it should work. Jean-Sébastien Guay wrote: > Keep up the great work! I will! Thanks a lot again! If you like to play around with osgHimmel, just download the demo (windows binaries on the googlecode site): in skybox.exe you can drag and drop 3d models into the scene, play with all the parameters, and livecode all shaders from within the GUI. Note that this is still in development and there are some unadressed bugs left. ------------------ Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=52051#52051 _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
