Very slow frame rate in landscape

Frame rate goes down below 4 FPS in landscape mode when using ES2 on Samsung i8910 and Sony-Ericsson Satio.

Whether I start the application in landscape mode or switch to landscape from portrait during the application life time I get very low frame rate in landscape mode. Switching back to portrait mode fixes the issue. Same application, same scene, same devices but using ES1 build does not have this problem. Satio is also flashing some residual render while running slow.

I must be doing something ES2 does not like. Any advice?

See also:

Slion2010-06-02 20:55:18

It does sound like an issue with the drivers though cause I cannot reliably reproduce the problem. By that I mean that after rebooting the devices landscape rendering works nicely. However I’m pretty sure it will occur again after sometimes playing with ES2. Could it be that my application is not cleaning something properly on exit?

I’m having the same problem on Vivaz Pro. Portrait mode is never showing that bug but landscape often is. Forcing a couple of screen rotation and/or OpenGL re-init sometimes gets ride of it.

The application is running slow and flashing some residual frame. So my scene is rendering fine like every second frame but every other frame appears to be showing a previous residual frame. I did hunt down for bugs in my framework for quite a while without luck.

Have you guys never seen anything like that?

Hi Silon,

Sorry for the slow reply.

I’ve never come across this issue before. Did you come across a workaround for this issue or determine the root cause of it? Is it possible to run your application on an OS other than Symbian? If so, do you still experience the same issue?

If this is still a problem your looking to solve, do you have a stripped down test case that exhibits the same issue that you can send to for investigation?

Thanks for looking back at that issue.

So far I could not find the root cause of that problem. I never tried to reproduce it using a minimalistic application. I cannot reproduce that bug on PC using the PowerVR ES2 emulator which is the only other environment I've run my program on.

It seems to affect only simplistic scenes and/or shaders. Only very low poly scenes without much texture fetch reproduce the problem. So it probably is not an issue for "real life" applications with richer scenes.

Still I'm looking forward to try this on the Nokia N8 which does not have PowerVR hardware I understand and see if that's indeed an issue with ES2 on SGX for Symbian.

Definitely an issue with ES2 driver for SGX on Symbian. In fact that problem is not showing on Nokia N8. But it is present in all Symbian^1 phones with SGX I tested: Satio, Vivaz Pro, Samsung i8910. I’m guessing the Vivaz would also exhibit the same issue. I suppose you won’t ever get a chance to fix it anyway since those phones are unlikely to get any firmware upgrade now.

Having said that the GPU of the Nokia N8 really sucks (at first glance). Nokia should really stick to PowerVR… Ok it does ES 2.0 but it delivers 6 frames per second on a scene the N95 was rendering at 32 FPS.

Slion2010-10-31 11:12:28