Hello, Sorry, I've abused from the term tearing. With tearing I was not referring to the effect of swapping buffers while the display is drawing a frame. I was talking about the acordion effect noticed along the edges between the tiles (maybe I should have also clarify that I placed the 4 windows in a 2x2 tiling scheme for rendering the same view using shears). That's my fault, I didn't thought it was misleading. Now everything should make sense (at least a bit more ;) ).
> Unless your display device is refreshing at 200 frames per second, It's a TFT at 75Hz > if you > are swapping buffers at 200 frames persecond and refreshing at a lower > rate > (60-85 hz) then you _are_ tearing - you can't escape that. Yes, there is tearing, in its right sense, but there is no accordion effect between tiles. However, believe me, the tearing is rather less noticeable that the accordion effect. At 200fps a period is 5ms, and 75Hz have a period of 13ms so at most you will see 2 swaps per refresh (at fullscreen). Maybe, because of the image persistence in the TFT and because there is not enough difference in the scene between frames the tearing is a bit concealed. On the other hand, if buffer swaps get serialized when syncing to vertical retrace, then you will the swap of the forth context will be delayed a minimum of 40ms from the swap on the first (it could be even worse if the first swap of the next frame overtakes the last of the previous, I'm not sure it this is possible anyway). That difference is four times the one you find without vertical retrace synchronization. > If you are seeing tearing then swapbuffers is _not_ synchronizing to > vertical retrace. (I'm certain of this). You're right, when synching there is no tearing, only accordion effect. Sorry again for the confussion, but I used tearing because in an horizontal separation, this and the accordion effect have the same visual appearance, at least in my case (actually both are two different application frames being displayed in the same display frame). Best regards, Juan _______________________________________________ osg-users mailing list [email protected] http://openscenegraph.net/mailman/listinfo/osg-users http://www.openscenegraph.org/
