On Friday 24 September 2004 18:48, Manuel Massing wrote: > Hello, > > > Anyway, I am going to give this also a shot and contact some companies > > that provide aerial/satellite image data, could anybody here provide the > > details concerning the requirements that need to be met for an image > > to be suitable to be used as a texture for FlightGear ? > > I've been lurking on this list for some time ( => pilot-wannabe :-) ), and > as the question for more accurate or more realistic scenery seems to be > quite recurrent, I'd like to present you our little terrain rendering > project at the University of Bonn (see [1]). Unfortunately, we do not have > a very informative webpage up yet, but you can download some old demo > videos and a paper describing the algorithms involved. > > As part of the project, we have developed a terrain rendering engine which > we will probably release under the GPL (or similar) in the near future, and > I would be willing and interested to do some work on integrating it with > flightgear. Please tell me what you think. To give you an overview, the > main features of the engine are: > > - out-of-core rendering of large datasets in realtime > - LOD approach with one pixel accuracy regarding geometry, shading and > textures > - compressed textures and geometry > - per-pixel normal map shading > - occlusion culling > - implemented in C++ / OpenGL > - currently runs under linux and win32 > > We are also currently building datasets out of the publically available > LandSat ETM true-color (28.5 m resolution) and SRTM-3 elevation data (~90 m > resolution) [2], which both have almost worldwide coverage. It probably > would be a good idea to integrate more accurate textures (if available) > near airports, or to add procedural details for low-altitude flights. > > To see what detail to expect from these Landsat datasets, here a few > screenshots of the Alps / Rhône valley + Lake Geneva, Corsica, and Cap Of > Good Hope. > > [Rhone valley] http://terrain.warped-space.de/rhonetal-lacleman.jpg > [Corsica] http://terrain.warped-space.de/corsica.jpg > [Cap Of Good Hope] http://terrain.warped-space.de/capetown.jpg > > To give you an idea, such a dataset including textures, normal maps and > geometry for a single UTM zone (see [3]) is about 250 MB in size. Geometry > size is negligible at about 5 MB per UTM tile, the corresponding normal > maps eat away about 60 MB, the rest is used by textures. The engine can > also handle higher resolution datasets, but they're not as easily and > consistently available for such a global setting (nor is it practical > looking at the amount of data), so adding localized detail is probably a > good solution. > > There would still be a fair amount of work left to integrate such an engine > into flightgear, even after the release of the engine, but given enough > interest, I'd like to work on the remaining issues (I guess on the > flightgear side e.g. defining and implementing a more loosely coupled API > for the terrain subsystem; scenery creation toolchain etc.). > > Please tell me if that sounds interesting / useable! >
This sounds very interesting. But i also have some questions about this engine. Is it a irregular grid or regular grid engine? If the latter is the case how many lod levels does the engine allow and is there a barrier if your viewpoint is to far away from the grid? If the lod level is high enough and there wouldn't be an altitude barrier then this would allow us to use such an engine for seemless planet rendering. In other words using a rocket in flightgear and fly into space or reentering earth from space using a space shuttle. This would also make sense for the X-15 aircraft. Then i have another question about the Landsat datasets. Where can i download this true color datasets? All i have found was the raw Landsat dataset which was divided into 7 channels. I merged the first 3 channels (the visible ones for blue, green and red) with gimp but the result was a true color picture that was somehow false colored, strictly speaking it was to much red and to less green So do you know a way how to merge these 3 channels in a way that the result looks really like a true color picture? Best Regards, Oliver C. _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
