Are there any ways to use web camera on qt 4.8?
On qt5.1.1 I saw example camera and I can use QCamera, but on qt4.8 I couldn't. Does somebody give examples?
There are no native camera support in Qt4. Use Qt5 or some thirdpaty libraries. For example - GStreamer.
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I have a Qt application that draws using Open GL. At some point I'm using a QQuickWindow associated to a QQuickRenderControl to draw a QML scene into a texture to later compose it in the final image.
Now, I'm considering porting OpenGL to Vulkan and I'm not sure if it is possible to do the same with this QML layer.
Reading Qt docs I found that
QQuickWindow uses a scene graph on top of OpenGL to render.
Do you think it is possible to port it to Vulkan? Perhaps overriding QQuickWindow and QQuickRenderControl? I'm not a Qt expert so perhaps someone can give me a better insight of the problem.
As of June 2019 and Qt 5.13, Qt Quick 2 supports the following backends:
OpenGL 2.0
OpenGL ES 2.0
Direct3D 12 (support is still experimental)
OpenVG
Software rendering
However, only OpenGL and OpenGL ES are fully functional. For instance some effects (like particles) do not work with the other banckends.
For more information about how to select a backend and what are the limitations of each backend I suggest to read the documentation: https://doc.qt.io/qt-5/qtquick-visualcanvas-adaptations.html
Regarding Vulkan specifically, Qt has added support to it since Qt 5.10.
However, the support is still very limited and does not cover Qt Quick.
Change will come in the future; quoting an email from Qt development mailing list:
A very early preview of Qt Quick for Vulkan, Metal, and D3D11 may come already in Qt 5.14, then evolve in 5.15 and beyond, with 6.0 as its final destination.
So rendering Qt Quick with Vulkan should be possible when Qt 6 will be out. The planned release date for Qt 6 is currently November 2020. In the mean time technical previews might be available starting with Qt 5.14.
I would not be too optimistic for anything before Qt 6 as (1) it will just be technical previews and (2) as far as I know, current official Qt binaries are not linked with Vulkan at all and you need to build Qt from source if you want to use Vulkan.
Is OpenGL mandatory in order to run a Qt application made of QML pages ?
Well, an implementation of OpenGL ES 2 is mandatory for Qt Quick 2, but that doesn't mean you need to use native OpenGL. On Windows you really should be using ANGLE, since on many Windows systems the installed OpenGL is either too old or broken.
Yes, with Qt Quick 2.0 OpenGL is a mandatory requirement.
I've been trying to make an application using Qt + OpenGL ES, so that it would run on devices but i can't seem to find any code on it, and the only few i could find wouldn't build. And when i searched for why it wasn't building people would say that i had to wait for a new version of Qt or something like that.
Anyone has ever done it? If so, there is a tutorial out there or something like that?
Examples for OpenGL ES 1.0 and OpenGL ES 2.0 are in examples/opengl/ of your Qt installation.
If you are targeting to Symbian, you need to wait Qt 4.7 and it's "experimental" OpenGL ES support for Symbian. With Maemo (N900), OpenGL ES 2.0 has been working since Qt 4.6.
Just as regular openGL - you just can't use a few features like pixel buffers
http://doc.qt.io/qt-5/windowsce-opengl.html
Qt OpenGL Nehe tutorials converted to the Qt environment
I haven't tried it yet, so hopefully will help.
before posting this quesiton i did extensive research on Forum nokia, Stackoverflow and developer.symbian.org but still unable to find solution to the problem
I am building an application that uses Symbian C++ (to get advanced network data which QT cant provide) and QT libs (for user interface and xml saving and so many other things). Now here is the problem, i cannot build and run Symbian Series 3 sdk (0.9 and o.8) with QT Designer nor Carbide C++. if i use the same approach with Series 60 5th edition, it works like a charm but combining both Symbian C++ and QT (tried 4.6 and 4.7) targeting N8, i am unable to do so.
1:Can someone advise about how to setup the environment in which we can blend Symbian and QT together.
2:Can someone help me in writing down the instuctions from point 1 (i,e pre requisites) and then running a sample code.
This thing is going on my nerves, i will really appreciate your help Stackoverflow!!
Is there any reason you need to build on the Symbian^3 SDK? A build for S60 5th will work on the N8, so unless you need APIs specific to Symbian^3, why not stick with the S60 5th SDK?
(I've had similar problems with the S^3 SDK, but now work with 5th without a hitch)
I have a question about supporting of QtConcurrent in Qt for Symbian. I use Qt 4.6.2 but I'dont understant how to use QtConcurrent. All works fine on Wice platform in the same version of QT, but doesn't work on Symbian. How to enable QtConcurrent, QFuture, QFutureWatcher?
Big thanks in advance for your answers!
QtConcurrent and QFuture are not implemented in Qt for Symbian yet: see Qt bug about that: https://bugreports.qt.io/browse/QTBUG-5182