>>> Thorsten suggested [1] separating foilage and trunk; is this what you >>> have in mind? > > At the moment I'm simply using 4 separate complete textures ; one for > each combination of summer/winter and clear/snow-covered. > > So I 'just' need straight pictures from summer and winter. Snow-covered > would be a bonus, though that can probably be added later. > > With that I can display different textures above and below the snowline > with no computational impact (well, a couple of additions and > multiplications at the vertex level plus an additional Uniform). On my > system there's no impact to frame rates. > > I've still to look at Thorsten's idea in detail (my code predates that > discussion) and don't expect to have the time to do so in the > foreseeable future.
Just to be clear - if we had textures, this is something I would do the work for since I suggested it, I'm not expecting Stuart to do this for me :-) (This is not to imply that I would object against Stuart giving a try, but as long as I can follow up an idea I like myself, I try not to fill someone else's to-do list). The reason for separating foilage would be to allow continuous autumn-color shifts and 'shed' leaves by overlaying a noisy alpha-channel. > I expect it to require additional texture lookup and some perlin noise > at a minimum so the perf impact might be significant. Depends on the hardware I guess. On my old GPU, the fragment pipeline was the bottleneck, and such an addition to the fragment shader would have been a clear no-go. My new GPU is almost always vertex-shader limited if it doesn't go to vsync, with the chief suspects being clouds, buildings and trees. So chances are I wouldn't even see additional texture lookups and noise functions, because the vertex shading dominates the execution speed of the tree code. So I would suggest to implement this as a high-quality option for those who have the hardware to crunch substantial fragment shaders and leave the current implementation as a fallback. * Thorsten ------------------------------------------------------------------------------ Precog is a next-generation analytics platform capable of advanced analytics on semi-structured data. The platform includes APIs for building apps and a phenomenal toolset for data science. Developers can use our toolset for easy data analysis & visualization. Get a free account! http://www2.precog.com/precogplatform/slashdotnewsletter _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
