Re: [Interest] [Qt3d] QSceneLoader in Thread
The worlds best article on the subject:
https://mayaposch.wordpress.com/2011/11/01/how-to-really-truly-use-qthreads-the-full-explanation/
Sent from my iPad
On Oct 10, 2018, at 2:11 PM, Jérôme Godbout
mailto:godbo...@amotus.ca>> wrote:
Make sure to check how QObject are related to a QThread. Each QObject belong to
a single QThread and cannot be used into other thread. If you need the object
into another thread to do processing or signal/slot, you will need the
QObject::moveToThread() function on each object first.
You might want to check if the moveToThread() does affect children too (I'm not
sure anymore), so you might only move the root parent or you might need to do
your own function to move all children too. You also make a lot of parentless
object into your code above, make sure this is what you want.
I did this with a secondary QQmlEngine that was executing some Qml declaration
into is own other thread and then move the resulting object back to the main
loop thread QQmlEngine. So it's doable but not too funny.
The GUI rendering can only work into the Main loop thread, take care if you do
some rendering of the scene that will be rendered on screen. The offscreen
rendering into buffer does't suffer from this limitation if I remember well.
Note this is not Qt3D directly, but my guess here is that it's proabbly working
the same way.
On Wed, 10 Oct 2018 at 08:01, Saif Suleiman
mailto:saifqahe...@gmail.com>> wrote:
Currently I am trying to import a scene in my Qt3d application. The problem is,
when creating an instance from QSceneLoader and set the sources QUrl then add
it to an Entity, it freezes the application until it finishes the importing. I
tried to put it in thread like :
void start()
{
qDebug() << "Thread";
QAspectEngine* pAs = new QAspectEngine();
pAs->registerAspect(new QRenderAspect());
QRenderSettings *renderSettings = new QRenderSettings();
renderSettings->setActiveFrameGraph(new Qt3DExtras::QForwardRenderer());
// Root entity
Qt3DCore::QEntity *sceneRoot2 = new Qt3DCore::QEntity();
sceneRoot2->addComponent(renderSettings);
pAs->setRootEntity(QSharedPointer(sceneRoot2));
Qt3DRender::QSceneLoader *sceneLoader = new Qt3DRender::QSceneLoader();
SceneWalker sceneWalker(sceneLoader);
QObject::connect(sceneLoader, ::QSceneLoader::statusChanged,
, ::onStatusChanged);
sceneLoader->setSource(QUrl::fromLocalFile("C:/Users/USER/Downloads/TreeTest.obj"));
sceneRoot2->addComponent(sceneLoader);
}
This fuction will run when the Qthread emit the started signal, but then i got
this : QObject::setParent: Cannot set parent, new parent is in a different
thread.
So i do not know how to import a scene in qt3d without freezing the app, can
any one help please.
Thanks in advance.
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Re: [Interest] [Qt3d] QSceneLoader in Thread
Make sure to check how QObject are related to a QThread. Each QObject
belong to a single QThread and cannot be used into other thread. If you
need the object into another thread to do processing or signal/slot, you
will need the QObject::moveToThread() function on each object first.
You might want to check if the moveToThread() does affect children too (I'm
not sure anymore), so you might only move the root parent or you might need
to do your own function to move all children too. You also make a lot of
parentless object into your code above, make sure this is what you want.
I did this with a secondary QQmlEngine that was executing some Qml
declaration into is own other thread and then move the resulting object
back to the main loop thread QQmlEngine. So it's doable but not too funny.
The GUI rendering can only work into the Main loop thread, take care if you
do some rendering of the scene that will be rendered on screen. The
offscreen rendering into buffer does't suffer from this limitation if I
remember well. Note this is not Qt3D directly, but my guess here is that
it's proabbly working the same way.
On Wed, 10 Oct 2018 at 08:01, Saif Suleiman wrote:
> Currently I am trying to import a scene in my Qt3d application. The
> problem is, when creating an instance from QSceneLoader and set the sources
> QUrl then add it to an Entity, it freezes the application until it finishes
> the importing. I tried to put it in thread like :
>
> void start(){
> qDebug() << "Thread";
>
> QAspectEngine* pAs = new QAspectEngine();
> pAs->registerAspect(new QRenderAspect());
>
> QRenderSettings *renderSettings = new QRenderSettings();
> renderSettings->setActiveFrameGraph(new Qt3DExtras::QForwardRenderer());
>
>// Root entity
>Qt3DCore::QEntity *sceneRoot2 = new Qt3DCore::QEntity();
>sceneRoot2->addComponent(renderSettings);
>
>pAs->setRootEntity(QSharedPointer(sceneRoot2));
>
>Qt3DRender::QSceneLoader *sceneLoader = new Qt3DRender::QSceneLoader();
>SceneWalker sceneWalker(sceneLoader);
>QObject::connect(sceneLoader, ::QSceneLoader::statusChanged,
> , ::onStatusChanged);
>
>
> sceneLoader->setSource(QUrl::fromLocalFile("C:/Users/USER/Downloads/TreeTest.obj"));
>sceneRoot2->addComponent(sceneLoader);
>
> }
>
> This fuction will run when the Qthread emit the started signal, but then i
> got this : QObject::setParent: Cannot set parent, new parent is in a
> different thread.
>
> So i do not know how to import a scene in qt3d without freezing the app,
> can any one help please.
> Thanks in advance.
> ___
> Interest mailing list
> Interest@qt-project.org
> http://lists.qt-project.org/mailman/listinfo/interest
>
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*Jérôme Godbout*Senior Software Developer
*p:* +1 (418) 800-1073 ext.:109
*m:* +1 (581) 777-0050
amotus.ca
[Interest] [Qt3d] QSceneLoader in Thread
Currently I am trying to import a scene in my Qt3d application. The problem
is, when creating an instance from QSceneLoader and set the sources QUrl
then add it to an Entity, it freezes the application until it finishes the
importing. I tried to put it in thread like :
void start(){
qDebug() << "Thread";
QAspectEngine* pAs = new QAspectEngine();
pAs->registerAspect(new QRenderAspect());
QRenderSettings *renderSettings = new QRenderSettings();
renderSettings->setActiveFrameGraph(new Qt3DExtras::QForwardRenderer());
// Root entity
Qt3DCore::QEntity *sceneRoot2 = new Qt3DCore::QEntity();
sceneRoot2->addComponent(renderSettings);
pAs->setRootEntity(QSharedPointer(sceneRoot2));
Qt3DRender::QSceneLoader *sceneLoader = new Qt3DRender::QSceneLoader();
SceneWalker sceneWalker(sceneLoader);
QObject::connect(sceneLoader,
::QSceneLoader::statusChanged, ,
::onStatusChanged);
sceneLoader->setSource(QUrl::fromLocalFile("C:/Users/USER/Downloads/TreeTest.obj"));
sceneRoot2->addComponent(sceneLoader);
}
This fuction will run when the Qthread emit the started signal, but then i
got this : QObject::setParent: Cannot set parent, new parent is in a
different thread.
So i do not know how to import a scene in qt3d without freezing the app,
can any one help please.
Thanks in advance.
___
Interest mailing list
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http://lists.qt-project.org/mailman/listinfo/interest
