Pixelmaps or billboard textures might be the OpenGL terminology. Animation studios might use the term "Particle Systems". 1980's game programmers would probably use the term "sprites", especially if their motion changed when you moved. In this case blowing off as the vehicle moved.
For snow, they would be partially transparent at the edges (alpha ->0 ) and darker in the middle, so that when they were pasted on top together, they would make that area of the screen go dark. Not sure about the description of rain accumulation - if it were the effect of water trickling down the window, Doing trickling raindrops would be tricky - you would definitely need a particle system with a surface threshold algorithm (marching cubes/triangles) and some surface tension physics to generate the geometry to do refraction. On the inside of the window, you'd want condensation effects - that would just be partially transparent gray. On Wed, Dec 1, 2010 at 3:17 PM, Andrew Lowe <a...@wht.com.au> wrote: > On 1/12/2010 6:15 PM, Trajce (Nick) Nikolov wrote: > >> Hi Community, >> >> any ideas/hints how to implement rain/snow accumulation on the screen >> (like >> for a driving sim)? >> >> >> -Nick >> > > A company I used to work for which did driving sims, mining trucks > in fact, just used a series of bitmaps - I might be using totally the wrong > buzzwords here, I've had my after work beer and the correct terms escape me. > The bit maps were generated by the graphics people and we just loaded them > up and overlayed them as needed. > > There was a series of overlays that corresponded to: > > 1) A few drops > > 2) More drops > > 3) Even more drops > > 4) quite a few drops > ... > ... > ... > ... > n) That many drop that in combination with a dusty windscreen, remember > this is of a mining truck in an iron ore mine in Australia, that the > windscreen has become mud. Then the user would turn on the wipers and a new > set of overlays would be used which corresponded to the windscreen wipers > going. > > These overlays were created by our graphic artists and we just > dumped them into the scene at the speed we needed to simulate the rain. In > other words the screen/rain/mud was not done dynamically with a snazzy > algorithm, it was basically "good old" page flipping animation. > > Nick, does this make sense? If not I'll revisit the topic in the > morning, it's currently 11.15pm, and try and make more sense. > > Regards, > Andrew > > _______________________________________________ > osg-users mailing list > osg-users@lists.openscenegraph.org > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >
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