Re: [Flightgear-devel] Demeter (was Re: FlightGear terrain engine)
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 David Megginson wrote: On 31/10/2007, Christian Buchner [EMAIL PROTECTED] wrote: I would like to get a few pointers where to look for information about the terrain engine that is currently used by Flight Gear. In particular about the irregular terrain mesh - how is it ... Our current terrain engine was great in the late 1990s (when MSFS still had a flat world), but it's pretty stale now, mainly from a lack of interest and the difficulty of understanding the code. It's actually deteriorated in some ways -- note that all the Great Lakes have been forced to sea level now, so that Lakes Huron, Michigan, and Superior are in deep gorges, and all the cities beside them are perched on cliff faces (that wasn't happening a couple of years ago). I'm not sure that we should really be maintaining our own terrain engine any more, though -- we should concentrate on aircraft models and flight dynamics, and try to interface with an existing engine. That depends on where your interests lie, I suppose. A flight simulator has specialized needs from a terrain engine: good close-up detail for near or on- earth operations, terrain stretching to a far horizon, no-pause loading of terrain from everywhere on the round earth, accurate material properties for ground polygons. I don't know of any free project that offers this. One promising prospect is Demeter, which works with OpenSceneGraph (already supported by FGFS): http://www.tbgsoftware.com/index.html Unfortunately, Demeter itself seems to have gone a bit stale -- some of the links from the site don't work any more, and it won't compile with the latest version of OSG. It does, however, support LOD and lots of other nice stuff (check out the screen shots!). Maybe someone should take it over if the maintainer has abandoned it, or fork it if the maintainer hasn't but is stalling on new releases. It doesn't do round-earth at all... The best thing we could do in FGFS, in the meantime, would be to isolate scenery-engine dependencies so that it's easy to switch to a new engine when it's ready. That's not a bad idea; isolating the scenery engine would make it viable as an independent project as well. I think we have the expertise, both on the production / GIS side and the programming side, to create a first-class world terrain and terrain engine that would be taken up by other projects too. I personally want to work on this, but I need to help get our OSG house in order first. I'll start a Wiki page with some of my ideas (which aren't very original). Tim - -- Red Hat France SARL, 171 Avenue Georges Clemenceau 92024 Nanterre Cedex, France. Siret n° 421 199 464 00056 -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.7 (GNU/Linux) Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org iD8DBQFHKYymeDhWHdXrDRURAqb6AJ9z96Jop7f3p7W4Ry64VMvJkE90LQCdF/Sf lWYlhMue+BYRO3Q7e1Dt9ew= =2vto -END PGP SIGNATURE- - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Demeter (was Re: FlightGear terrain engine)
On 01/11/2007, Tim Moore [EMAIL PROTECTED] wrote: ... we should concentrate on aircraft models and flight dynamics, and try to interface with an existing engine. That depends on where your interests lie, I suppose. By we, I meant the Flightgear project, not the individuals in it. I would also be very interested in contributing to a terrain engine, but I think it probably would need its own maintainer and team of core developers who were focusing primarily on it, rather than building it as a sideshow to FlightGear, especially since it would have to come with a suite of editing tools to help people manipulate GIS data and manually tweak scenery. All the best, David - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Demeter (was Re: FlightGear terrain engine)
Hello, Few thoughts as FlightGear moves to osg there is a nice virtual terrain project which is integrates with osg. The site for the project is http://www.vterrain.org/ and some papers are here http://www.vterrain.org/LOD/Papers/. Personally I like Thatcher Ulrich adaptive quadtrees approach ( which allows to load chunks in runtime and thus it is possible to ) the approach is implemented in Soul Ride game which source could be obtained here http://sourceforge.net/projects/soulride/ ( this one specific implementation does not feature loading new chunks but I seen the java code with the functionality. anyhow there are quite a bit of approaches which are presented at http://www.vterrain.org/LOD/Papers/ and some are more hardware friendly than adaptive quadtrees. Regards Sergey Kurdakov http://www.sim-ai.org/simplestgame.htm http://www.sim-ai.org/FlightGearlesson.htm On 11/1/07, Tim Moore [EMAIL PROTECTED] wrote: A flight simulator has specialized needs from a terrain engine: good close-up detail for near or on- earth operations, terrain stretching to a far horizon, no-pause loading of terrain from everywhere on the round earth, accurate material properties for ground polygons. I don't know of any free project that offers this. I think we have the expertise, both on the production / GIS side and the programming side, to create a first-class world terrain and terrain engine that would be taken up by other projects too. I personally want to work on this, but I need to help get our OSG house in order first. I'll start a Wiki page with some of my ideas (which aren't very original). - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Demeter (was Re: FlightGear terrain engine)
On 01/11/2007, Sergey [EMAIL PROTECTED] wrote: as FlightGear moves to osg there is a nice virtual terrain project which is integrates with osg. The site for the project is http://www.vterrain.org/ and some papers are here http://www.vterrain.org/LOD/Papers/. Excellent. It looks like a good start, but there is a strange culture around the site -- for example, you have to request a download instead of simply downloading the source, even though it seems to have a BSD-style license. I wonder if most of the developers are coming from the Windows world, and don't quite get the norms of open source yet. All the best, David - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Demeter (was Re: FlightGear terrain engine)
Hello David. you have to request a download instead of simply downloading the source, even though it seems to have a BSD-style license. I do not know exact rationale why this system to get a code is in place, still the pass goes without problems and the author is from linux/unix world himself ( to my know ). Regards sergey On 11/1/07, David Megginson wrote: On 01/11/2007, Sergey wrote: as FlightGear moves to osg there is a nice virtual terrain project which is integrates with osg. The site for the project is http://www.vterrain.org/ and some papers are here http://www.vterrain.org/LOD/Papers/. Excellent. It looks like a good start, but there is a strange culture around the site -- for example, you have to request a download instead of simply downloading the source, even though it seems to have a BSD-style license. I wonder if most of the developers are coming from the Windows world, and don't quite get the norms of open source yet. - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Demeter (was Re: FlightGear terrain engine)
On Thursday 01 November 2007 09:32, Curtis Olson wrote: Certainly we could and should take a look at cleaning up the scenery render engine API within FlightGear. I think the problem here is about sceney _data_ generation as much as about the scenery engine itself. The sceney generation process is overly complex, many people who tried didn't get far for one reason or another. Then, we have experts who know how everything ties together but simply don't have the time to maintain the code. Finally, when scenery actually gets generated, it either lost a lot of details or worst, has a lot of errors. There are a few opensource libraries that are dedicated to the features that you have mentioned. GTS, for example, can do continious LODs as well as CSG. The great thing about using existing libraries is that these libraries are purposely designed, dedicated to what they do, and are maintained by experts, instead of being hacks that are written once and hardly get looked at afterwards. So, not only will we able to cut holes into the terrain for runways, we will also be able to do so better and much more efficiently. Ampere - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
[Flightgear-devel] Demeter (was Re: FlightGear terrain engine)
On 31/10/2007, Christian Buchner [EMAIL PROTECTED] wrote: I would like to get a few pointers where to look for information about the terrain engine that is currently used by Flight Gear. In particular about the irregular terrain mesh - how is it created (at runtime or offline) and how does photo texture currently get mapped onto terrain - how are roads and other terrain features added? (is it all vector or is it texture maps) Our current terrain engine was great in the late 1990s (when MSFS still had a flat world), but it's pretty stale now, mainly from a lack of interest and the difficulty of understanding the code. It's actually deteriorated in some ways -- note that all the Great Lakes have been forced to sea level now, so that Lakes Huron, Michigan, and Superior are in deep gorges, and all the cities beside them are perched on cliff faces (that wasn't happening a couple of years ago). I'm not sure that we should really be maintaining our own terrain engine any more, though -- we should concentrate on aircraft models and flight dynamics, and try to interface with an existing engine. One promising prospect is Demeter, which works with OpenSceneGraph (already supported by FGFS): http://www.tbgsoftware.com/index.html Unfortunately, Demeter itself seems to have gone a bit stale -- some of the links from the site don't work any more, and it won't compile with the latest version of OSG. It does, however, support LOD and lots of other nice stuff (check out the screen shots!). Maybe someone should take it over if the maintainer has abandoned it, or fork it if the maintainer hasn't but is stalling on new releases. The best thing we could do in FGFS, in the meantime, would be to isolate scenery-engine dependencies so that it's easy to switch to a new engine when it's ready. All the best, David - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
