Fullscreen change problem

Posts: 19
Joined: 2008.05
Post: #1

i have quite a problem with full screnn change, on most mac computers it works just fine but on for imac 24" there is a problem when user starts the game in windowed mode and than switches to full screen it shows some peaces of textures and parts of desktop, if the game is started in full screen than it all seems to be ok, whats strange that i don't have this problem on my mac's and that only 2 people reported this so far. I'm using agl carbon and opengl,
windowed and full screen mode has separate contexts, during mode change a new context is created which shares resources with previous one and than the old context is disposed of.
You can try to test it, here is a download link:


This bug is pretty hard to eliminate since i cant reproduce it, if you have any ideas on what could cause this please let me know.

thanks Jerry
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Posts: 254
Joined: 2005.10
Post: #2
I have similar problems on my MacBook when playing Civ IV, but only if I have some other graphically intensive programs running. I have no idea what would cause that other than the graphics card doesn't have enough memory maybe. It sounds like this kind of problem might actually be Apple's/Nvidia's fault.
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Posts: 81
Joined: 2007.05
Post: #3
That sounds like some kind of memory was allocated but the memory was not cleared. I wonder if you do a glClear and swap the buffer a couple of times if it would make a difference? I've seen some example code doing that but its on the exit out of fullscreen. Not sure...
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Posts: 19
Joined: 2008.05
Post: #4
I have done some work with ppl who are helping me with this bug and currently i know that this problem is caused by wide screen aspect correction. Game is 1024x786 and to keep original aspect ratio (in full screen) I'm using GL_EXT_framebuffer_object. I'm performing a check if extension is available on machine but even if its there i get this bug.
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Posts: 446
Joined: 2002.09
Post: #5
Are you using glScissor to limit the viewport in fullscreen mode? IIRC, I've seen some nasty artifacts on some systems when doing that in the past.

For the record, I don't see this problem with your app on my 24" iMac w/8600GS, but it appears to be picking the non-stretched 1024x768 mode which should behave like a native 4:3 screen as far as any app is concerned.
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Posts: 3,591
Joined: 2003.06
Post: #6
I just use scissor and change the size of the viewport to maintain aspect -- no need for an FBO (unless you wanna scale it I guess... but then why not just restrict the available full screen rez in that case?).
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