I have a brand new iMac, 3ghz, 512MB video card, the fastest one you can currently buy.

I installed Civ4, unpatched as of yet, and noticed that no matter what resolution I run it at, and regardless of whether it is in full screen or windowed, I am seeing tearing while moving the board around.

Tearing usually happens when a 3D game is not synced to the vertical refresh rate of the display, to ensure that the display buffer is not overwritten while it's still being drawn on the screen.

I didn't have this problem with the Windows version, and I find it quite annoying and a serious flaw as this flicker is very distracting.

Does anyone know how to force all OpenGL apps to be synced to vertical refresh? Either from within Civ4's settings or from Leopard's OpenGL settings?

Double-buffering on Mac OS X
[Chris Hanson] August 19, 2006 21:08:37 EDT
Mac OS X does double-buffering itself, including synchronization with vertical retrace, and has since the release of Mac OS X Server 1.0 in 1999. Basically, all drawing on the system is double-buffered and flushing windows to the screen always occurs during vertical retrace. The only time this isn't true is when using OpenGL, because this effectively lets you bypass the window server and draw directly to the screen yourself. Even there, though, the way you normally interact with OpenGL causes it to only push bits to the display during vertical retrace.

So. If the OGL calls are made correctly from within Civ4 then the multiple buffering required to eliminate tearing should be automatic within OS X. However, the Civ4 code could be bypassing the window server as above. If that's the case then there's not a lot you can do.

Note that the Civ4 porting - including the most recent patches - was done before a lot of the latest video and CPU hardware was delivered by Apple. Aspyr support will probably tell you that they can't guarantee performance on hardware that didn't exist at the time of release. The tearing may only be visible now because the frame rates on your high performance Mac are exceeding the refresh rate of the display.

In any case, patching Civ4 would probably be a good idea. There have been several updates since the first DVDs were produced, and maybe there were some fixes among them. Aspyr would certainly ask you to do so before attempting to investigate any ticket you raise with them on the subject.

So. If the OGL calls are made correctly from within Civ4 then the multiple buffering required to eliminate tearing should be automatic within OS X. However, the Civ4 code could be bypassing the window server as above. If that's the case then there's not a lot you can do.

Note that the Civ4 porting - including the most recent patches - was done before a lot of the latest video and CPU hardware was delivered by Apple. Aspyr support will probably tell you that they can't guarantee performance on hardware that didn't exist at the time of release. The tearing may only be visible now because the frame rates on your high performance Mac are exceeding the refresh rate of the display.

In any case, patching Civ4 would probably be a good idea. There have been several updates since the first DVDs were produced, and maybe there were some fixes among them. Aspyr would certainly ask you to do so before attempting to investigate any ticket you raise with them on the subject.

Agree I'll patch it first before talking to Aspyre.

That said, this is not a new feature. It's a driver level option that is available to any DirectX or OpenGL app going back decade+. There is on Windows the ability to force all 3D apps to be locked to VSYNCH, the card can force it.

The question is (i'm new to mac), does OS X expose these specific NVidia settings? Or does NVidia offer a tool to do this?

I'll check the latest patch later, but throw the above out there for now.

Question though, does nobody else see this problem? That's another place to look. Am I the only one?

Sorry this is a bit OT. I can't find any way to tweak the settings on my new 24" iMac with NVidia 8800.

Apple doesn't provide any video driver tweaks to my knowledge. Macs are supposed to "just work".

There are some OpenGL tools in the Developer tools package, that comes as an optional install with OS X. But I think they are mainly for profiling and debugging, not for tuning the drivers.

I think the problem is that you have a Mac.

=P

So I patched it and I still get image tearing. This is pretty crappy. I mean the iMac and the NVidia 8800 GT that comes with it is more than capable of rendering without image tearing, any video card is no matter how weak.

Did Aspyr really just neglect to enable the ability to vsynch?

Is there no way to force vsynch globally on Leopard through some OpenGL setting?

Asking the same question more than once here is unlikely to get you a different answer! I recommend you raise a ticket with Aspyr.

Please note that Macs have never been famed as gaming machines, and Mac versions of game software are often (not always) second rate. If you are looking for the best gaming experience on your Mac then you really need to run Windows in Bootcamp.

Asking the same question more than once here is unlikely to get you a different answer! I recommend you raise a ticket with Aspyr.

Please note that Macs have never been famed as gaming machines, and Mac versions of game software are often (not always) second rate. If you are looking for the best gaming experience on your Mac then you really need to run Windows in Bootcamp.

Thanks I'll raise a ticket with Aspyr.

THat said, Macs may not be targeted at gamers, but they did put powerful 3D processors in these machines that are relevant to any 3d field, be it animation, architecture, or whatever. All of these fields require vsynch to remove the annoying tearing, so I would not let anyone off the hook for this.

Oddly though nobody here answered whether they see the same issue.

There's only you and me here, and I don't play Civ4! :D

Thanks I'll raise a ticket with Aspyr.

THat said, Macs may not be targeted at gamers, but they did put powerful 3D processors in these machines that are relevant to any 3d field, be it animation, architecture, or whatever. All of these fields require vsynch to remove the annoying tearing, so I would not let anyone off the hook for this.

Oddly though nobody here answered whether they see the same issue.

I've been running the game on a Mac Pro with an X1900 XT since it came out and it works OK for me, but everyone is different. Please define "tearing" since I may have seen a bit of it but not considered it a problem. Also, I have a 20" monitor and you probably have a 24" iMac, right?