Hi Sean,
in fact, I'll be interested in contributing with the development of Qt3D.
I have never contributed to an opensource project like Qt so a little help
to start contributing will be great.
After I found that bug, I fix it in my code (just dont delete the
rootEntity in Qt3DWindow but create another entity in my side below the
qt3dwindow one) and thee QBuffer bug appeared.
Basically, when I destroy the scene I also destroy the different components
that ware attached to the scene, and this destroys the Qt3DRender::QBuffer
object, but it doesn't free the VBO in the GPU.
Would it be possible to have some information in how Qt3D works in low
level (something more that an explanation of what a ECS is), so I can try
to contribute in this project.
Thanks
2016-10-05 12:35 GMT+02:00 Sean Harmer <sean.har...@kdab.com>:
> Hi,
>
> that looks like a plain ol' bug. Please file a JIRA and if you want to fix
> it
> then please feel free to do so. If you need help getting started with
> contributions just ask.
>
> Thanks for the feedback!
>
> Sean
>
> On Wednesday 05 October 2016 01:29:35 Juan Jose Casafranca wrote:
> > Hi Sean,
> >
> > I've looking the Qt3DWindow code in the repo. I have seen that the
> > setRootEntity only works well if the window is not shown.
> >
> > During the expose event, if the userRoot is set as a child of the root.
> If
> > after the exposeEvent I call setRootEntity, it will change the m_userRoot
> > entity pointer, but will not set it as a child of m_root and will not
> > detach the previous m_rootEntity. Is this on purpose? Should we create a
> > rootEntity that should stay there for the whole execution? Shouldn't be
> > possible to just change the m_rootEntity in Qt3DWindow and sets this to
> be
> > to the new child of m_root?
> >
> > To summarize:
> > This is the Qt5.7, 5.7.1, 5.8 and dev code:
> >
> > void Qt3DWindow::setRootEntity(Qt3DCore::QEntity *root){
> > Q_ASSERT(!isVisible());
> > m_userRoot = root;}
> >
> >
> > And I dont understand why is not something like:
> >
> > void Qt3DWindow::setRootEntity(Qt3DCore::QEntity *root){
> > Q_ASSERT(!isVisible());
> >
> > m_userRoot = root;
> >
> > m_userRoot->setParent(m_root);
> >
> > }
> >
> >
> > Thanks for your time!
> >
> > 2016-10-03 17:26 GMT+02:00 Juan Jose Casafranca <jjcas...@gmail.com>:
> > > Hi Sean,
> > > thanks for your fast reply.
> > >
> > > I dont know what is a JIRA. Anyway, I have prepared a very simple
> example
> > > where I can reproduce one of the problems I was explaining in my
> previous
> > > message.
> > >
> > > I go through the code:
> > > The main creates the QApplication, a SceneManager and a timer to call
> > > periodycally a scenemanager slot.
> > > The SceneManager, during ctor, creates a Qt3DWindow, a root entity and
> > > calls the changeScene slot.
> > > The changeScene slot destroys the rootEntity (destroying that way all
> the
> > > children) and recreates it. Then it create a new geometry (which
> basically
> > > for this example consist on a red plane) and configures the camera.
> > >
> > > Right now the window show a red plane... great, no problem.
> > >
> > > When the timer timeouts and the changeScene is called again, the
> process
> > > is reapeated, but now, no red plane is shown. This is exactly the same
> > > problem I'm having in the complete code. I dont know why I'm having
> this
> > > behavior. With this example, the buffers are correctly deleted, so I
> > > imagine I have another problem in the complete code.
> > >
> > > Could you provide me some feedback?
> > >
> > > Thanks!
> > >
> > > 2016-10-03 13:57 GMT+02:00 Sean Harmer <s...@theharmers.co.uk>:
> > >> Hi,
> > >>
> > >> could you file a JIRA please ideally along with a small test case that
> > >> reproduces the issue.
> > >>
> > >> Many thanks!
> > >>
> > >> Sean
> > >>
> > >> On Monday 03 October 2016 13:40:36 Juan José Casafranca wrote:
> > >> > Hello!
> > >> >
> > >> > I'm posting to act some questions about Qt3D.
> > >> >
> > >> > I'm trying to show some information for my program. This information
> > >>
> > >> consist
> > >>
> > >> > on a regular grid (I'm painting the lines that define the voxels), a
> > >> > distance map (in each voxel vertex I store a distance value) and the
> > >> > sources for the distance (zones where distance is 0)
> > >> >
> > >> > The software supports resizing the grid or changing the sources so
> the
> > >>
> > >> views
> > >>
> > >> > must be updated accordingly. To achieve that, I emit a signal when a
> > >>
> > >> change
> > >>
> > >> > in the distance or the grid is done and connect that signal to a
> slot
> > >>
> > >> that
> > >>
> > >> > performs the scene preparation. It isn't the best solution but for
> now
> > >>
> > >> is
> > >>
> > >> > enough.
> > >> >
> > >> > The scene preparation slots cleans the previously allocated scene
> > >> > (m_rootEntity->deleteLater()) and reconstructs the scene.
> > >> >
> > >> > The reconstruction generates the geometry data for the different
> things
> > >>
> > >> I
> > >>
> > >> > want to view, creates the renderer and the materials and adds this
> > >> > components to different entities. Finally, this entities are added
> to
> > >>
> > >> the
> > >>
> > >> > root entity.
> > >> >
> > >> > To reduce code paths, the first view also performs this steps
> (removes
> > >>
> > >> the
> > >>
> > >> > previously scene, which is null) and creates the new one. This works
> > >>
> > >> well.
> > >>
> > >> > My problem is when trying to delete an existing scene. I have been
> > >>
> > >> debugging
> > >>
> > >> > with gDEBugger and I have seen that buffers are not deleted (I
> imagine
> > >>
> > >> that
> > >>
> > >> > VAO are also kept) though the buffers are constructed with the
> geometry
> > >>
> > >> as
> > >>
> > >> > parent, and the geometry es an entity children (the entity is delete
> > >>
> > >> when I
> > >>
> > >> > delete m_rootEntity).
> > >> >
> > >> > After 2 or 3 remeshing steps, the screen goes black and I cant see
> any
> > >> > information.
> > >> >
> > >> > I'm using the Qt3D version shipped with Qt 5.7.
> > >> >
> > >> > Any idea what I'm doing wrong? I can provide some code if you ask
> for
> > >>
> > >> it,
> > >>
> > >> > but as the software I'm developing is big, I prefer to show the code
> > >>
> > >> when
> > >>
> > >> > you ask for it, so I don't fill this question with a lot of code
> that
> > >> > wouldn't be necessary.
> > >> >
> > >> > Thanks!
> > >> > _______________________________________________
> > >> > Interest mailing list
> > >> > Interest@qt-project.org
> > >> > http://lists.qt-project.org/mailman/listinfo/interest
> > >>
> > >> _______________________________________________
> > >> Interest mailing list
> > >> Interest@qt-project.org
> > >> http://lists.qt-project.org/mailman/listinfo/interest
>
> --
> Dr Sean Harmer | sean.har...@kdab.com | Managing Director UK
> KDAB (UK) Ltd, a KDAB Group company
> Tel. +44 (0)1625 809908; Sweden (HQ) +46-563-540090
> Mobile: +44 (0)7545 140604
> KDAB - Qt Experts
>
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