Thorsten > Sent: 13 June 2013 07:25 > To: FlightGear developers discussions > Subject: [Flightgear-devel] Rembrandt performance > > > I've had a my first short go with Rembrandt on my new machine yesterday. > The test case was a small airport in Sulawesi (Indonesia) (WAAJ) where I'm > discovering a very nice scenery. There are no static or shared models to > speak of, there is some forest around, and that's basically it. I chose fair > weather, i.e. a modest cloud cover. The aircraft was the PAF team DR-400 in > the latest version. > > All Rembrandt functions work out of the box very nicely. I started with a > dawn scene and tried the landing light illumination first. This gave me a good > 30 fps. I then switched to noon and tried shadows. I have to say that since I > am more the VFR virtual pilot, I almost never fly at night, lightmap for internal > illumination work fine for me, and so shadows are the main selling point of > Rembrandt which attracts me. > > The initial shadows coming up by default were rather ragged and flickery (the > last is a problem for me, I tend to get headache when looking at some sort of > flickers unfortunately), so I played with shadow map size, cascade ranges and > filtering till I had a nice result. To my dismay, at this point the framerate > counter gave me a mere 15 fps (no shader effects on at this point). > > For comparison, the same scene renders in Atmospheric Light Scattering with > all details maxed out (including tree motion) with solid 60 fps. > > Am I doing anything wrong? Did I miss any optimization which makes the > shadows run fast enough? Am I just unlucky and my system has some > unspecified problems chewing Rembrandt? Does anyone else get > significantly higher framerate out of shadows with filtering? I am running on > an GeForce GTX 670M, which is usually a pretty fast beast. > > I mean, maybe it's just me, but this appears to confirm a suspicion I wrote > earlier that trying to pack ALS functionality into Rembrandt will end up being > way too slow. If I have a mere 15 fps before any shaders, then I can't > reasonably apply 800 lines of extra computations and expect no performance > impact. > > Does anyone have a semi-solid case which would argue that this would be > fast enough? I'm sort of trying to make my mind up if I should focus on that > before the next release (which is why I did the test), but it seems hopeless > to me. It's okay and flyable as it stands, but I don't see how to cram lots of > extra stuff in. >
I think your numbers are pretty representative. 15 fps is definitely not enough IMO. I would say that 30 fps would be a good aiming point. Smoothness is also a factor. Vivian ------------------------------------------------------------------------------ This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
