-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Harald JOHNSEN wrote: > Vivian Meazza wrote: > >> John Wojnaroski >> >> >> ... >>> >>> I've yet to see a system that IMHO tops what Mark Harris did >>> a few years >>> ago part of his doctoral thesis. >>> >>> See http://www.lfstech.com/img/sfo_clouds.jpg. >>> >>> Someone made a decision a few years ago to replace rather >>> than improve. >>> Think we all lost a very promising >>> implementation, but there might be an opportunity to recover >>> what was lost. >>> >>> Stay tuned... >>> >>> John >>> >>> >>> > There are methods today to do real volumetric display with slices from a > 3d volume, so yes there is method to draw clouds a lot better than those. > The old implementation of the Harris code in fg was using hard coded > cloud shape, hard coded cloud relative position between clouds, hard > coded group of cloud around ksfo. The next implementation could do > clouds everywhere on the planet, parametrable cloud shapes in an xml > file (Harris was using a non editable binary format), parametrable cloud > formation type. > Wasn't that some kind of improvement ? What could have been improved > then is some new texture for the cloud particles or new shapes or > whatever, frankly anybody could enhance what I did. > Hm wait, you did not realize that Harris clouds are *slow* and ppl on > this list were using depreciated hardware... > Using his method to render the clouds is very easy to integrate in our code. For what it's worth, I recently ported Harris' old SkyWorks code, on which his contribution to FlightGear was based, to Linux for some playing around. I'll make that code available soon, but I have to agree with Harald's critique of the old code. In particular, the key illumination step for a particular cloud is *very* expensive -- in the SkyWorks code it repeatedly reads back color values from the frame buffer for each particle in a cloud -- which is why particular clouds were hard-coded. Harris has since described algorithms that are more dynamic and which require heavy-duty GPU firepower, something that always seems to be sensitive topic here.
A free cloud library based on Harris' work, integratable with other OSG applications, would attract a large following and would be a very cool thing. In the mean time, in order to learn some of the issues, it would be very good to port Harald's plib-based work into OSG FlightGear. Tim -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (GNU/Linux) Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org iD8DBQFG2sU4eDhWHdXrDRURAtmqAKCKm0pFfFyXFWE6YaCsjXZ/AuunhwCg4x3R 8D1t6PzDu8llfSo89C2w9As= =dLHl -----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
