From: Christopher D. Johnson (cubicwts++at++excite.com)
Date: 12/08/2005 09:25:14
Greetings all. I am currently working on a flight simulator that is run on a system with the following specs:
Dell Workstation 470 w/ Dual Intel Xeon 3.2ghz processors
1gb DDR2 3200 memory
1 Asus GeForce 6600 w/ dual monitor output
Fedora Core 3 OS
The simulation is displayed on 2 LCD screens, with each screen getting it's own X-Window, one above the other. The upper screen/window shows the "out the window" view and HUD overlay. The lower screen/window represents our 2D panel with various cockpit switches and controls, as well as 2 MPCD video areas, and is also a touch-screen. The upper and the lower windows are each driven by a seperate executable, and we have a simulation executable that controls flow of data throughout the system. Since the upper screen was the only screen that showed any 3D terrain/models in the past, Performer 3.2 was only loaded into the upper executable. The lower executable only initialized OpenGL libraries for 2D drawing.
In the past these 2 MPCD areas only had to draw in 2D, via various OpenGL calls, to draw lines and symbols representing things like RADAR B-sweep and various other symbology. A recent software upgrade we have performer required that 3D terrain be displayed on the LOWER screen in one of the MPCD areas, so Performer was integrated into the lower executable as well.
Immediately after we installed Performer, we noticed the lower screen became very laggy. The 3D terrain was choppy and the RADAR b-sweep line ( a simple line drawn with OpenGL calls) was choppy as well. We decided the video card wasn't up to the task and that some system memory was required. We first installed an NVidia GeForce 7800 dual output card to replace our old card. Immediately our 3D terrain displayed on the lower screen lost some of the choppiness and the system overall feels much smoother, but the framerates are still falling into the 11-15fps range when we call psDrawChanStats. We have also put an extra gig of memory in the system and things got marginally better, but there is still a problem.
Something that is odd that we have noticed is that with all this going on on the lower display/window, the UPPER fps is NEVER affected, it runs at a consistent 35fps and looks great. It does not seem to have been affected adversely at all from the extra drag on system resources (remember we only have one video card w/ dual output in this system). It seems like the upper screen/window is getting the best performance while the lower has to suffer with framerate issues. Is the lower being starved for resources because the upper is hogging them? I seem to remember vaguely reading somewhere that with OpenGL and a dual output video card you could run into situations where one screen runs extremely well while the other screen suffers greatly in performance.
Any input/clues/insights at this point would be greatly appreciated. Thank you all.
Christopher D. Johnson
AV-8B Harrier II Simulators
ISEO Support Team
Cherry Point, NC
252-466-4542
252-466-4538
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This archive was generated by hypermail 2b29 : Thu Dec 08 2005 - 09:25:29 PST