-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Curtis Olson wrote: | On Mon, Feb 11, 2008 at 8:39 AM, LeeE wrote: ... | | I think I'd suspect the 110 miles figure (if that's a ground level | value) as well, not only because that's a lot of atmosphere to see | through but also because of curvature. | | I tried a quick Google to see if I could find any rules/formulae for | visibility due to atmospheric conditions but didn't hit anything. | It'll be interesting if you can come up with rules or a formulae | from your analysis of a large set of METAR data. | | | There appears to be some strangeness (bug?) in how the OSG version | handles the far clipping plane. It seems to set the clip plane | somewhere beyond the maximum visibility (weather-wise) but it seems to | also clip the sky in some situations when it shouldn't. Last time I | poked around, it looked like we were setup to use OSG's automatic | near/far clip plane mechanism with no way to override it ourselves. I | haven't dug into OSG far enough yet to learn how to fix this.
In OSG, the far plane is fixed at 120km; the sky is drawn at a radius of 80km from the viewer. That sky radius may be the cause of many of the artifacts described here; turning off depth buffer writes when drawing the sky would be a simple fix. The scenery is paged in out to the visibility distance from the viewer's position at sea level, using /environment/visibility-m. The OSG clip-plane calculation is disabled. I haven't had a chance to look at this in detail, but I have seen some of the wacky high-altitude effects. One possibility for the white sky is a problem calculating the sky color / fog color. I'll try turning off depth buffer writes as I described above. Does anyone have a simple way to provoke the wackiness that doesn't involve METAR? Thanks, Tim -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (GNU/Linux) Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org iD8DBQFHuAEXeDhWHdXrDRURAgZ+AJ4lO6A5oBYS5AqOcFJ4QbnbAcqPJACdFX8e 1xwq1IXrtA/N5brhAp25hQk= =4dF/ -----END PGP SIGNATURE----- ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
