Particles Rain slow down fps after loosing Focus

[fabre.cedric]

Hello,
I have a small problem with a simple particles rain.

When my windows has the focus all work correctly but when I loose the focus (I stop the rendering when loosing focus) to work on another application and return on our software, if the particles Rain are enabled and collision enabled, the fps drop down and all run slowly. If the setCollision is set to 0, there is no problem.

Have you got any idea ?
Thanks

[silent]

fabre.cedric

That's very interesting behavior, hard to tell what's going on here. If possible, could you please send us a minimal test scene with this reproduction (maybe it can be reproduced even in an empty new project or some default C++ sample)?

Thanks!

[fabre.cedric]

I'll try to reproduce it to a minimal test scene.
Just one precision,When my app is slow, if I move my camera out of the bouding box of the collisioned 3D scene all run correctly.

[fabre.cedric]

Okay I can reproduce it on the editor but I know why this is so slow...
I have to many particles.The editor say I have 6000 particles for the rain...

[romain.janil]

Hi, not rain/particle related (in my case it seems to be clutters/grass), but I experience same issue (posted a video in another post), switching focus from app/editor to another app (on windows), and going back freezes fps down to 5, for a long time. Maybe it's to do with some OS/ driver weirdness added recently?

[fabre.cedric]

Hello, I work with two computer (home and office) and I have the same problem on the two computer.
I think this is related to the computation of the collision intersection when application is not updated...Maybe a time Based computation ?

romain.janil : If you use collision, could you please try to disable it ?

Silent: Have you got any idea how to reduce the speed of particles because I have a video encoder module in our software and the particles are too speed. I have tried with linear danmping and velocity but that doesn't work correctly.

Thanks.

[silent]

Unfortunately, without a small test scene it's not possible to understand what's going on.

Try to check mircoprofiler to see what is causing this lag. Maybe disabling collisions with player will help? Try to stop particles when window is out of focus.

[fabre.cedric]

MinimalTestScene.zipIf you want to try with this. Thanks

[silent]

Can you please export this scene as .upackage file? https://developer.unigine.com/en/docs/2.14.1/editor2/assets_workflow/assets_migration

[fabre.cedric]

Yes sure :)MinimalTestScene.upackage

[silent]

I've also tried to reproduce this while waited for package:  Looks like everything is working just fine? 

[fabre.cedric]

Have you tried this scene in the Unigine Editor because I have the same problem in the Editor and in our application that use QT ?
I havent precised but using version 2.14.1.1.

[silent]

I also have zero issues with Editor and this scene (can alttab and return back). What's your current GPU and OS (version & build number)?

[fabre.cedric]

I have the same problem on two computer :

At my home :
I work on windows 10 Pro 10.0.19041.
On intel I7 4790 with 16gb of ram and an rtx 2080s 8Gb driver 471.11.

On office :
I work on windows 10 Pro 10.0.19041.
On intel I9 9900 KF with 64 Gb of Ram and Rtx 3070 8Gb latest driver.

The problem appear more frequently on my personnal computer because this is a baby compared to my office computer :D

[fabre.cedric]

I think the problem appear when the computation of the collision take more time with more than 5000 particles and many polygons to test in the scene (depend of computer power)
When window loosing focus, the computation is stopped but maybe have you internaly a timer or other that never stopped ? And when window get Focus there is to many particles to compute for collisions at the same time because timer is not stopped and the process is waiting GPU. I dont know if I'm clear in my theory ?
I can reduce a litle the number of particles to avoid this problem.

Have you got any idea how to slow down the particles speed "for snow not rain" to capture video ?
When capturing I force the framerate at 5 fps to avoid loosing frames but the particles are too speed.
Thanks

[fabre.cedric]

On the editor.
That really strange you don't have this bug.

[silent]

Yeah, here is my situation (i5 10600KF, GTX 1060, Windows 10 build 19042.1288):

 I've tried both (DX11 / GL) and float / double builds. So it's maybe related to the newer GPUs (will test on more machines after 2.15 release).