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[Gear VR] GPU particles and horrible performance

motorsepmotorsep Posts: 1,321 Oculus Start Member
I was learning / working with particles for my project and it turned out that GPU particles are horribly slow (and probably bugged/broken) in Gear VR.

Here is the video with CPU particles (performance drops are due to video recording):



Once the drone crashes and particle system attached to it is deactivated, fps is still good.

When I made smoke trail on the drone flying over in the arc to be GPU particles (exact same look and rate), fps dropped to the floor and even after particle system got deactivated and visibility was turned off, fps still stayed super low.

My guess is it's a question to Epic, but I am sharing my finding here too.

Comments

  • motorsepmotorsep Posts: 1,321 Oculus Start Member
    So, is this a bug or a feature ?
  • aussieburgerVRaussieburgerVR Posts: 187 Oculus Start Member
    I also noticed problems with GPU particles on android devices in the past such as: https://answers.unrealengine.com/questions/530587/googlevr-gearvr-particle-emitter-moving-with-hmd.html

    I switched to CPU and everything runs fine :) My game was GPU limited anyway so was better to use CPU particles. Can't you just use CPU as well?

  • motorsepmotorsep Posts: 1,321 Oculus Start Member
    That's what I use now, but GPU would allow for a lot more particles, especially on S7/S8, and vector field effects.
  • motorsepmotorsep Posts: 1,321 Oculus Start Member
    I planned a few particle effects that aren't possible to achieve with CPU particles due to the need to use vector fields. I wonder if it's UE4 issue or hardware issue or both. I guess at this point I am gonna give up on GPU particles and when (if rather) it's sorted out I can probably just patch the app/game.
  • motorsepmotorsep Posts: 1,321 Oculus Start Member
    @imperativity

    Just wondering if this was looked at by chance  :)
  • imperativityimperativity Posts: 3,587 Valuable Player
    It has not been looked at yet. I'll see what I can do.
  • motorsepmotorsep Posts: 1,321 Oculus Start Member
    bumping it up...
  • Mohammed_hashimMohammed_hashim Posts: 73 Oculus Start Member
    edited February 7
    motorsep  Every single issue I'm facing now with porting my project into GearVR I google and I found your post, looks like you really suffered from all of these issues before us Since yesterday I spent numerous hours trying to find out what's wrong my project and I found out its due to GPU particle, never crossed my mind GPU particle will have performance issue on gearVR till I made many tests and now I found your post which confirms I'm not alone. I wish you made a post regarding all of these issues you faced in one single post, I might do one later. the bad news is all of the issues have been posted here in forms but still no official answer.

    imperativityNinjaGaijin Could we get an answer for this, please?
  • motorsepmotorsep Posts: 1,321 Oculus Start Member
    well, I got no time to revisit my posts into a single one. This issue should have never been an issue to begin with, or Oculus should have clearly outline what works and what doesn't in mobile VR. 

    If only UE4 was their #1 engine for mobile VR.. But, it's not..
  • Mohammed_hashimMohammed_hashim Posts: 73 Oculus Start Member
    motorsep said:
    well, I got no time to revisit my posts into a single one. This issue should have never been an issue to begin with, or Oculus should have clearly outline what works and what doesn't in mobile VR. 

    If only UE4 was their #1 engine for mobile VR.. But, it's not..
    Exactly, I spent my last 3 weeks only doing trial and error, nothing i could find about limitations or bugs.
    HDR on with multiview--> one eye black 
    HDR off --> game crash
    particle enable -- >  game crash due material have either having "time, panner or MicroUV" which lead to crash probably not supported on GPU or a bug.
    Distance node ---> game crash. 
    Pixel depth ---> game crash
    And the list goes on etc...  And every single crash I had to spend a few hours or even days to find out the reason behind it. I'm sure I'm not alone with this and all of us facing the same issue and you already beat us here and probably you spent more time than me since you were one of the first who faced these issues and I'm sure most of these issues are bugs and not limitation.
    I spent more time fixing crashes and finding our limitation than the time I spent on my own game. I thought one of the good things about such Engine is you don't care about such thing and you invest your time on your game but I was wrong. the good thing is we can find each other's posts which confirm to us that it's not our project problem and its engine limitation/bugs. but the bad thing seems there aren't many devs using UE4 for GearVR as there are very few posts regarding GearVR and UE4. 
  • Mohammed_hashimMohammed_hashim Posts: 73 Oculus Start Member
    motorsep Btw may I ask if you faced any problem with audio having cracking noise with GearVR? Its been a week and I couldn't find a fix for my project regarding this issue.
  • aussieburgerVRaussieburgerVR Posts: 187 Oculus Start Member
    motorsep Btw may I ask if you faced any problem with audio having cracking noise with GearVR? Its been a week and I couldn't find a fix for my project regarding this issue.
    I had this as well and I fixed it by increasing the buffer size:

    See my comment Sep 27 '17 at 8:35 PM
    https://answers.unrealengine.com/questions/593219/android-new-audiomixerandroid-in-416p1-results-cra.html
  • Mohammed_hashimMohammed_hashim Posts: 73 Oculus Start Member
    motorsep Btw may I ask if you faced any problem with audio having cracking noise with GearVR? Its been a week and I couldn't find a fix for my project regarding this issue.
    I had this as well and I fixed it by increasing the buffer size:

    See my comment Sep 27 '17 at 8:35 PM
    https://answers.unrealengine.com/questions/593219/android-new-audiomixerandroid-in-416p1-results-cra.html
    I will answer you on the original audio thread to keep this post clean for others. 
    https://forums.oculusvr.com/developer/discussion/comment/661106
  • motorsepmotorsep Posts: 1,321 Oculus Start Member
    motorsep Btw may I ask if you faced any problem with audio having cracking noise with GearVR? Its been a week and I couldn't find a fix for my project regarding this issue.
    I had this as well and I fixed it by increasing the buffer size:

    See my comment Sep 27 '17 at 8:35 PM
    https://answers.unrealengine.com/questions/593219/android-new-audiomixerandroid-in-416p1-results-cra.html
    Is this still an issue for Go and UE 4.21.2 ?
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