Jim Wilson wrote: > > It is also applied to cloud layers, with an artefact though : when > > there are few clouds in a valley and you are below, you can see > > the sky through mountains. I experienced that flying in the > > Mont Blanc area recently. > > Could we just dynamically reorder the rendering of the layers based on > location of the viewer rather than using the alpha-test? This problem > actually shows up at KSFO most days with metar turned on.
I noticed that at KSFO too. The problem with clouds is rather tough. Without alpha-test, we wouldn't see anything above clouds from below. The bottom of clouds ( the side of the quad pointing downward ) is drawn before the scene and the upper side after so we can see clouds through bridges or trees. This was needed before alpha test was used in models ( although I think alpha-test is not used yet for trees ). We can try to come back to the previous situation where all sides of clouds are drawn after the scene and rely on alpha test. There will be an ugly, not blended border around transparent patterns but It could be acceptable if it only show up at close distance. We can also begin to think about a multi pass method that would : 1. draw the clouds above the viewer without depth update, 2. draw the scene, 3 .redraw the clouds above with depth test With an impact on framerate due to double writing and problem like the one Melchior is experiencing with overlapping semi transparent objects. Haven't thought about it much of that. -Fred _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
