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OverviewFelgo 3 Support (Qt 5) › emulation Layer crashed (1:0) – when using designer and QtQuick 2.x

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  • #8560


    Hi All,
    just started with v-play and wanted to do few tutorials.
    Unfortunately I have an issue with:

    import Felgo 3.0 // for accessing the Felgo gaming components
    import QtQuick 2.0 // for accessing all default QML elements
    GameWindow {
        Rectangle {
            color: "black"
            anchors.fill: parent
        Scene {
            Rectangle {
                color: "lightgrey"
                x: 100
                y: 50
                width: 100
                height: 40
                Text {
                    text: "Press me"
                    color: "black"
                    anchors.centerIn: parent


    When going to design, getting: emulation Layer crashed (1:0)
    I found one topic related to similar issue but with v-play 1.0
    In the end it breaks with GameWindow(switching to Rectangle fixes the issue with QtQuick 2.0).
    With QtQuick 1.0 GameWindow works fine.

    I tried to find any schedule/plan of porting “stuff” to new v-play 2.0/QtQuick 2.0 but couldn’t find one.
    Is it just porting issue ? Not all elements are ported yet and available in design ?

    It is not a big issue for me but would be nice to know if it’s a bug or you know this and have it planned to fix.
    For now I switch to QtQuick 1.0 when want to see the preview.

    Linux 64(Ubuntu). Qt 5.4 with V-play 2.0 added to existed instance(by repository). Default settings.


    Felgo Team

    Hi Marcin,

    thanks for reporting the issue with GameWindow & designer, we were not aware of it before!

    You can just replace the GameWindow with a temporary Item and the designer should work again. Anyway, you probably want to lay out your design in sub-components, e.g. by adding an own qml file for each Scene in your app or game, and then the designer works again. I’d advise against using Felgo 1, because some component’s API changed since then and got improved (see the changelog for the changes since Felgo 2.0).

    Cheers, Chris



    Thank you @Christian. Will use your advice.
    Thank you also for more technical hints but fortunately I already did it(I have few years of exp in programming, maybe not games related but have heard about few good practices or design patterns)- so it was quite natural.
    So far really enjoy your product.
    If you now aware of the issue maybe we should close this topic ? It’s up to you.


    Felgo Team

    Hi Marcin,

    we can keep the post active, maybe it is also beneficial to read for other developers.

    Cheers, Chris



    I have this same problem.  I’m not sure that I understood the solution properly.

    I replaced “GameWindow” with “Item” in the “New-Empty” project template, and I get a crash:


    file:///Users/mgregory/Documents/build-test-Desktop_Qt_5_4_0_clang_64bit-Debug/test.app/Contents/Resources/qml/Main.qml:15 Cannot assign to non-existent property “activeScene”

    The program has unexpectedly finished.

    /Users/mgregory/Documents/build-test-Desktop_Qt_5_4_0_clang_64bit-Debug/test.app/Contents/MacOS/test crashed




    Felgo Team


    the replacement is only meant while using the Qt Designer (but not when you then run the application). When you run the application, switch the Item back to a GameWindow so the correct root item is used and all properties are known.

    Anyway, it is better to split up your Scenes into several qml files and then edit each of them individually, then you will not have this issue in Qt Designer.

    Cheers, Chris



    im getting  error  on my newly created project when i click designer ,this error “this qml file contains features which are not supported by qt quick designer” when i try to ignore it, its gives me new error “qt quick emulation layer crashed” guys please help solve this one. pls it seems no exact solution in the internet so far been searching for it almost 6hrs . what should i do?


    Felgo Team

    Hi Kean!

    The designer often has troubles if there’s already a lot of logic and different components in your QML code, which results in such error messages. We usually recommend to use the designer mainly in the initial creation/design phase of the components you create.
    You can try using the designer with a new Qt Quick Component (right click on QML folder of your project tree -> Add New -> Qt -> QML File (Qt Quick 2)). The designer should work fine in this case.

    Best, Günther

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