> I don't think it's quite that bad. In a deferred shader like Rembrandt, > the ALS would run in the deferred lighting pass. While it's true that the > heavy work is done in a fragment shader, it only runs for each pixel on > the screen, not for every rendered fragment.
Yes - but you need to execute ~ 200 additional lines per screen pixel just to get the light at every point right in the scene. Then come ~150 additional lines to compute fog. As for the graphical goodies of terrain texturing, that's all in the fragment shader and contributes another 300 lines or so in total, and now that's only done per screen pixel, because I always use a trivial first pass to fill the z-buffer and render terrain only when actually seen. So the fragment shader will get ~650 additional lines to execute for every screen terrain pixel. Have you looked at terrain-haze-ultra.frag ? That has 720 lines of code in total, part of it subroutines which are called a few times. It is true that we currently render terrain obscured by the panel due to the near/far camera issue - but I have a crude panel masking code and a good feeling of how much this saves you. > Also, in many cases the sky > would take up a large portion of the out-the-window scene; is computing ALS > for > the blue sky as expensive as for an object in the scene? Not to mention > that you don't need to run ALS in the cockpit... Yes, it does now as well. But you want the sim well-behaved not only in level flight, but also when you descend or do aerobatics. So you have to design for a clouded sky (which reverses the argument, looking at the sky then becomes very bad) or a steep descent when only terrain is visible - it doesn't do to have a framework which only runs when half the screen is sky :-) And you do have to use ALS light computations for the cockpit to get consistent light (you don't need fog or pixel postprocessing). In the end, I guess we'll see how bad it is... * Thorsten ------------------------------------------------------------------------------ Try New Relic Now & We'll Send You this Cool Shirt New Relic is the only SaaS-based application performance monitoring service that delivers powerful full stack analytics. Optimize and monitor your browser, app, & servers with just a few lines of code. Try New Relic and get this awesome Nerd Life shirt! http://p.sf.net/sfu/newrelic_d2d_apr _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
