>> Mathias, thanks for the great work! I'm now into the precip thing porting. > > I assume you know that there is some precipitation stuff already in OSG ? > I currently have no idea if it's ready to serve as a replacement of > what's currently in FlightGear/PLIB but it might be worth having a look
Of course, the first thing I ran when I first managed to compile the OSG is their precip demo. The plib-branch rain is GL_LINES based, mapped on an imaginary "precipitation cone" surface, and it doesn't branch the ssg (plib's scene graph), rather, it just gets drawn imperatively (as opposed to in-scenegraph callbacks) via direct GL calls at some point during the rendering. The cone is not properly clipped, which creates some funny artifacts when you look back on the runway you've just taken off from --- you sort of see the rain showering down through the asphalt. I have a prototype that is rolling-texture-based (Harald's idea). It looks pretty much like the OSG precipitation demo and suffers from the same ugly artifact that the demo has which I haven't eliminated - the stitches of the textured faces are very ugly when the texture is rolling. My prototype is uglier than the GL_LINES-based one and causes visible FPS decay (the GL_LINES-based one doesn't have any visible FPS impact!) on my hardware, which is pretty low-end (described earlier in this thread ;-) ). This is the reason I have never felt it mature enough to have it checked in, even with the up-side that it would bring in some kind of snow in addition to rain (just different texture and animation parameters, mostly same algorithm - unless it's light snow, which means that I need to get into the particle system modeling - never been there as well so far :) ). I had started to work on improving the visual aspects of the textured-based prototype by trying to do multitexturing of the same cone (hoping to blur the visual irregularities by rolling differently various layers of the texturing). I expect big help from OSG here as it has multitexturing support built-in; also, some of the things might be offset to the in-GPU-pipeline code which, I heard, is also supported (never tried that myself yet either, but eager to try). Finally, the clipping stuff will hopefully be easier to solve when the precip cone becomes part of the scenegraph. > at it. Volumetric shaders are in the works as well .... Volumetric shaders will come in handy later, when I have to port the 3d clouds. V ------------------------------------------------------------------------- SF.net email is sponsored by: A Better Job is Waiting for You - Find it Now. Check out Slashdot's new job board. Browse through tons of technical jobs posted by companies looking to hire people just like you. http://jobs.slashdot.org/ _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
