Harald JOHNSEN > > Vivian Meazza wrote: > > >Mathias Fröhlich wrote > > > > > > > > > >>On Mittwoch 15 Juni 2005 11:00, Vivian Meazza wrote: > >> > >> > >>>>When browsing Mark Harris' web page I got the impression that he > >>>>simulates the > >>>>airflow. > >>>> > >>>> > >>>This one? > >>> > >>>http://www.markmark.net/clouds/ > >>> > >>>I can't find any reference in the site or the papers there to > simulating > >>>airflow. It just renders clouds. > >>> > >>> > >>http://www.markmark.net/cloudsim/index.html > >> > >>Look into that. I believed that this was integrated somehow. That looks > >>phantastic and does things like that. > >>Watch the video on the bottom of that page. > >> > >> > >> > > > >Wonderful - just what we need! However, where's the code? I don't think > it's > >what we have. The OpenGL stuff for download from Mark's site just renders > >cloud. This is "Simulation of Cloud Dynamics on Graphics Hardware" > > > >>From his paper: > > > >"5. Hardware Implementation > > > >As mentioned before, we perform all of the numerical > >computation for our cloud simulator in the programmable, > >floating point fragment unit of a graphics processor." > > > >Hmmm. Have I got this one wrong? > > > >Mark's code (OpenGL) renders up to 51 fixed shape clouds. His lighting > and > >shading is good. I like the way the aircraft penetrates cloud from an > >outside view. Harald's clouds are nicer, more varied, but perhaps not > quite > >as well lit and shaded. The cloud penetration from an outside view could > be > >improved (and I'm sure will be). Mark's code does not seem to be under > >active development, while Harald's is. I therefore support the retirement > of > >Mark's OpenGL code. > > > >Of course, if we can go the "Simulation of Cloud Dynamics on Graphics > >Hardware" route, then wow! All bets are off. > > > >Anyone know how to program graphics hardware so that any/all cards would > >work? > > > >V. > > > > > > > > > On Harris pages there is two different things. > One is about cloud rendering - physical aspect of scattering of light > and technical implementation using dynamic billboards, etc. > The other is about simulating the formation of clouds (and simulating > fluids in general). > The 'Skywork' code available on his site and integrated in FG only > handle the rendering, the simulation of formation of clouds is usually > non real time anyway. It could be done realltime of course, it all > depends of the degree of realism one wants. Other papers show how to do > that with non physical rules and still have nice results. > See Dobashi and Nishita paper : > http://nis-lab.is.s.u-tokyo.ac.jp/~nis/abs_sig.html#sig00 > > About the current lighting of clouds : I admit that it is very > simplistic but it has at least the advantage of being light > for the cpu and the graphic card. > Now it is possible to integrate the Harris lighting method with the > existing code and have something perhaps not so far > from his rendering. This is easy to do, I could make a prototype (err > when I have a free moment). >
That would be very nice indeed; then we would have the best of both worlds. The cloud penetration method is probably the biggest difference visually. V. _______________________________________________ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
