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QOpenGLWidget VSync

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  • M Offline
    M Offline
    mcleary
    wrote on 25 Feb 2020, 10:22 last edited by
    #10

    I'll see if I can try it today. Will report back.

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    • M Offline
      M Offline
      mcleary
      wrote on 25 Feb 2020, 19:19 last edited by mcleary
      #11

      Is it that what you're talking about? As you can see, all widgets are running at 60fps.

      Capture.PNG

      R 1 Reply Last reply 25 Feb 2020, 20:43
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      • M mcleary
        25 Feb 2020, 19:19

        Is it that what you're talking about? As you can see, all widgets are running at 60fps.

        Capture.PNG

        R Offline
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        rtavakko
        wrote on 25 Feb 2020, 20:43 last edited by rtavakko
        #12

        @mcleary Thanks for trying it, thats exactly it! I added a second top level window in main and that caused the framerate for both winows and their child widgets to be divided in half.

        I just finished modifying the contextinfo example also creating two RenderWindow objects contained by two QWidgets in a single window and the two render at the correct 60 Hz refresh rate since each has a separate context. I think that's what I'll need to do but I'm not sure if this just my machine or its Windows or its just the way it is overall.

        M 1 Reply Last reply 26 Feb 2020, 10:10
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        • R rtavakko
          25 Feb 2020, 20:43

          @mcleary Thanks for trying it, thats exactly it! I added a second top level window in main and that caused the framerate for both winows and their child widgets to be divided in half.

          I just finished modifying the contextinfo example also creating two RenderWindow objects contained by two QWidgets in a single window and the two render at the correct 60 Hz refresh rate since each has a separate context. I think that's what I'll need to do but I'm not sure if this just my machine or its Windows or its just the way it is overall.

          M Offline
          M Offline
          mcleary
          wrote on 26 Feb 2020, 10:10 last edited by
          #13

          @rtavakko I also tried creating a new top level window but I still have no problems. Hopefully you can find the problem

          R 1 Reply Last reply 26 Feb 2020, 16:07
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          • M mcleary
            26 Feb 2020, 10:10

            @rtavakko I also tried creating a new top level window but I still have no problems. Hopefully you can find the problem

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            rtavakko
            wrote on 26 Feb 2020, 16:07 last edited by rtavakko
            #14

            @mcleary Thanks again for trying it! I also ran the same code with two top level widgets on another PC and it worked ok so I'm guessing this is something with my laptop. I'm not sure if its still recommended to give each OpenGL widget its own context to make sure the code runs the same way on different PCs.

            M 1 Reply Last reply 27 Feb 2020, 09:26
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            • R rtavakko
              26 Feb 2020, 16:07

              @mcleary Thanks again for trying it! I also ran the same code with two top level widgets on another PC and it worked ok so I'm guessing this is something with my laptop. I'm not sure if its still recommended to give each OpenGL widget its own context to make sure the code runs the same way on different PCs.

              M Offline
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              mcleary
              wrote on 27 Feb 2020, 09:26 last edited by
              #15

              @rtavakko If you absolutely need to share the contexts then I guess you should try to find the problem with your laptop. Which graphics processor do you have on the laptop? Is the driver updated?

              R 1 Reply Last reply 27 Feb 2020, 11:28
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              • M mcleary
                27 Feb 2020, 09:26

                @rtavakko If you absolutely need to share the contexts then I guess you should try to find the problem with your laptop. Which graphics processor do you have on the laptop? Is the driver updated?

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                rtavakko
                wrote on 27 Feb 2020, 11:28 last edited by
                #16

                @mcleary Good point. I updated the drivers recently (about a month ago). My laptop specs are:

                GPU: GeForce GTX 950M
                OS + Driver: Windows 10, driver NVIDIA 4.5.0 385.54
                Qt version: 5.12.0 MINGW (64 bit)

                I also have an Intel HD Graphics 530 (NVIDIA Optimus tech) for the built-in display which may have something to do with this. I've set my GTX 950M for OpenGL rendering and as the high-performance card. I'll dig a little deeper to see what could be the issue and update the thread.

                M 1 Reply Last reply 27 Feb 2020, 11:39
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                • R rtavakko
                  27 Feb 2020, 11:28

                  @mcleary Good point. I updated the drivers recently (about a month ago). My laptop specs are:

                  GPU: GeForce GTX 950M
                  OS + Driver: Windows 10, driver NVIDIA 4.5.0 385.54
                  Qt version: 5.12.0 MINGW (64 bit)

                  I also have an Intel HD Graphics 530 (NVIDIA Optimus tech) for the built-in display which may have something to do with this. I've set my GTX 950M for OpenGL rendering and as the high-performance card. I'll dig a little deeper to see what could be the issue and update the thread.

                  M Offline
                  M Offline
                  mcleary
                  wrote on 27 Feb 2020, 11:39 last edited by
                  #17

                  @rtavakko You could also try the MSVC build of Qt. I don't know if you are willing to install Visual Studio just to test this but it might be worth a shot.

                  R 1 Reply Last reply 27 Feb 2020, 16:09
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                  • M mcleary
                    27 Feb 2020, 11:39

                    @rtavakko You could also try the MSVC build of Qt. I don't know if you are willing to install Visual Studio just to test this but it might be worth a shot.

                    R Offline
                    R Offline
                    rtavakko
                    wrote on 27 Feb 2020, 16:09 last edited by
                    #18

                    @mcleary I tried the QT MSVC 2017 compiler with the same results. My Optimus setup has betrayed me before...

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                    • P Offline
                      P Offline
                      Patterson
                      wrote on 9 Mar 2020, 08:26 last edited by Patterson 3 Nov 2020, 08:53
                      #19

                      Could you provide more details of your issue, such as screenshot of FPS, Monitor type, and the application you run. Note there are a set of applications can override v-sync settings in-app McDVOICE

                      R 1 Reply Last reply 9 Jun 2020, 00:55
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                      • P Patterson
                        9 Mar 2020, 08:26

                        Could you provide more details of your issue, such as screenshot of FPS, Monitor type, and the application you run. Note there are a set of applications can override v-sync settings in-app McDVOICE

                        R Offline
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                        rtavakko
                        wrote on 9 Jun 2020, 00:55 last edited by
                        #20

                        @Patterson sure, I will get more details on this and post here

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                          riyana
                          Banned
                          wrote on 19 Dec 2020, 08:26 last edited by
                          #21
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                          • R Offline
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                            rtavakko
                            wrote on 13 Jan 2021, 21:05 last edited by
                            #22

                            @mcleary @Patterson

                            Its been a long time since this thread was started but I think it makes sense to post the updates here. I put together a basic project with native OpenGL and also using Qt's QOffscreenSurface and QWindow classes.

                            The github repository can be found here:

                            https://github.com/rtavakko/VSync

                            In this setup there is a single renderer that render to an FBO texture using its own thread and 3 display windows that share the GUI thread with all of them sharing OpenGL contexts together.

                            On my machine I see a clear lag with VSync on when there are 2 or more display windows. Turning VSync off clears the lag. The calcualted FPS values do not indicate any issues in either case which doesn't help but I see a clear difference when I start the application with say 2 displays and then close one of them.

                            I have my internal laptop display and an RCA RT1970 (both running at 1920x1080 - 60Hz) and both connected to my integrated Intel HD 530 GPU. My discrete GPU is an NVIDIA GeForce GTX 950M and I'm running Qt 5.12.0 MSVC2017 64 bit.

                            I'll dig in further myself also with other machines but if anyone has any ideas on what could be causing this, it would really help debug further.

                            Cheers!

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                            • Mylincoln PortalM Offline
                              Mylincoln PortalM Offline
                              Mylincoln Portal
                              Banned
                              wrote on 24 Sept 2021, 08:13 last edited by
                              #23
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                                liamerickson
                                Banned
                                wrote on 4 Feb 2022, 11:22 last edited by liamerickson 2 Apr 2022, 11:23
                                #24
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