Hans Fugal > Sent: 26 July 2007 14:57 > To: FlightGear developers discussions > Subject: Re: [Flightgear-devel] Broken Clouds > > > On 7/26/07, Vivian Meazza <[EMAIL PROTECTED]> wrote: > > Hans Fugal > > > I have never seen or heard of any problem with osg and > clouds of any > > sort. Xnview reports no errors in cirrus.rgba, or with any of the > > textures. Perhaps you have corrupted the clouds textures > locally? Did > > you open them in any editor before you saw the weird effects? Of > > course, people might be just accepting the weirdness, and not > > reporting it. > > Jester, jentron, and I did some investigating last night. The > textures in question seem to be a less-common format that > some programs understand and others do not. For example, > IrfanView and ImageMagick both treat cirrus.rgba similarly - > it looks something like this: > http://hans.fugal.net/tmp/fg/cirrus-abstractart.png . I think > we can agree this is not what the sky should look like. Some > programs refuse to open it at all, complaining that they > don't recognize the format. > > Jester has a better understanding about just what this format > is, but I believe the salient features are 2-channel: > greyscale with alpha. ImageMagick's identify(1) reports them > as PseudoColor images (vs > DirectColor)
That's what I would expect, but Melchior is more knowledgeable than I. > Gimp opens them fine, as does "osgviewer --image > cirrus.rgba". The latter is most important, it means that OSG > itself can handle this format. So we likely are looking at a > memory corruption bug in OSG when this particular type of > image is loaded. Something about the way things work on intel > macs is causing the corruption to manifest itself where as it > goes unnoticed on linux by sheer luck. Just a theory anyway. On Windows, too. > Incidentally, I have observed in both linux and osx in fg/osg > that cloud layers don't work quite like I'd expect. If the > weather is scattered clouds at 3000 ft and overcast at 5000, > then when I'm sitting on the runway I see blue sky between > the scattered clouds. It's not until I go above 3000 that > suddenly there's overcast sky above me. > I'm rather afraid that this last is a "feature" rather than a "bug". As I understand it, it is a consequence of the way osg orders/handles transparencies. Not good at all. Vivian ------------------------------------------------------------------------- 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
