Re: [Flightgear-devel] Runway lighting
Curtis L. Olson wrote: Paul Surgeon wrote: I played around with some runway lighting today to see if textured polygons are feasible. Here is what textured, billboard runway lights look like : http://surgdom.hollosite.com/flightgear/screenshots/index.html With 6 * 1 ft runways all in view at one time my frame rate dropped from 50 down to 20 FPS on an old Ti 4200. I think 6 * 1 ft runways should pretty much cater for any large airport. That's close to 5000 runway lights. This is just a hardcoded test to see what the performance impact is if one uses a brute force approach with zero performance enhancements. One could probably cull in between lights beyond certain distances which would help performance and look a bit better from a distance. Also I'm not sure what sort of impact billboarding and distance scaling has on performance - it would probably be faster if I had fixed polygons. If my Ti4200 can do the job then I'm sure newer video cards like the nVidia FX 5700 and up should handle these lights quite nicely. One thing we would need to figure out before we could head down this path would be a way to hide runway lights that are viewed from behind. Approach and runway lights are directional and pointed directly at aircraft arriving on the glide slope. So as you view them off axis they will be dimmer and when viewed from behind you shouldn't see them at all. Currently lights are actually a triangle drawn in point mode with two of the verticies set to zero alpha. This way backface culling hides the lights from behind. But if we switch to some sort of billboarded quad for lights, we lose this capability. We would either need to come up with some clever trick, write a new ssg selector node with this sort of functionality, or use vertex shaders which plib doesn't support. Any ideas? Curt. Altough the billboard itself always faces the POV, you can still set the normal the way the real light would be pointing to, them set a diffuse light on the POV and enable backface culling. I suppose performance hit should be minimal for TnL hardware. Regards, Tiago ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
Re: [Flightgear-devel] fgrun improvements
Vivian Meazza wrote: Dave Martin wrote: On Monday 24 Jan 2005 13:37, Oliver C. wrote: On Monday 24 January 2005 11:05, Erik Hofman wrote: Vivian Meazza wrote: Thanks for this explanation. Why does it only seem to work one way? The description 'enhanced lighting' is not particularly helpful. Oh, this is about enhanced (runway) lighting. That's a different story, I was talking about specular highlights which the original was talking about also. No, i was talking about enhanced runway lightning, this is what i get when running flightgear with this option: --enable-enhanced-lighting I was not talking about specular highlights. Why is it so expensive of frame-rate? This is very hardware and driver dependent. Some OpenGL features are just not implemented in hardware on some display adapters. The only consumer videocards we have today are from Ati and NVidia, do their newest models support this? If not, then we should move it to the advanced options. I also want to mention, that MS FS2004 has something similar, but without framerate drop, so there must be another way to display runway lights in such a way. Best Regards, Oliver C. I've also been confused by the monumental frame drop that even the simple runway lighting can produce at airports such as EGLL. And I do have a fairly hefty system which has been known to run graphical behemoths like Doom3 at a fair lick. The obvious response from the 'non-programmers' perspective ie: 'user' is: Why on earth do these little dots bring my new Model-X video card to its knees? So what's the crack? ;) Simple answer - too many vertices. Someone will give us the right answer -Erik Regards, Vivian After reading the glPointSize doc, I think the problem is in using point sizes bigger than 1 and point antialiasing at the same time I can't test it now, can someone do it? just disable GL_POINT_SMOOTH and see it there is an fps improvement Regards, Tiago ___ Flightgear-devel mailing list Flightgear-devel@flightgear.org http://mail.flightgear.org/mailman/listinfo/flightgear-devel 2f585eeea02e2c79d7b1d8c4963bae2d
