QEGLPlatformContext::makeCurrent:eglError - qt

I am working on Qt Quick [camera] application in jetson board. When I am launching and selecting camera from combobox for streaming in the application, It is throwing error
"QEGLPlatformContext::makeCurrent: eglError: 3009, this: 0x67d4d0"
Please help to fix this issue. Thanks in advance.

I encountered the same problem on my Jetson and made some investigation. Probably it had the same origin as yours. QEGLPlatformContext is always created with only support of EGL Window surfaces although its subclasses (at least QEGLXcbPlatformContext) may also use a EGL PBuffer surface. And actually this result in 3009 (EGL_BAD_MATCH) error when you try to bind the context with an offscreen (pbuffer) surface.
I've filed a bug where you can find the description of a dirty fix which helped me. It might help you also. On Ubuntu QEGLPlatformContext and QEGLPbuffer classes are part of libqt5gui5 package. Good luck!

Related

Qt6 circular gauge issue

I am developing a qml app in qt5 with circular gauge. I want to port application qt 6. But in qt 6 qtquick extras is missing, so circular gauge is not available. Is qt planning to make it available in next releases of qt6? What can I do instead of using circular gauge in qt6?
Is there anyone who knows about it?
As far as I know there are no plans yet to port it to Qt 6. You could create a suggestion on Jira to express your interest in having it.
The code is here and here if you want to try to port it yourself or just use parts of it (keeping in mind the license, which is LGPL).
As you stated in the question, CircularGauge is not available in Qt6. So what can you do?
As a minimal effort, you can substitute CircularGauge with a functional similar component, for instance, RangeSlider. Of course, a RangeSlider looks nothing like a CircularGauge, but, it will, at least, allow you to compile and run your application. It will give you an application to test whilst you decide your options.
Then, as others have stated, you need to spend more effort allocated to porting. If you refer to the source code of CircularGauge, you see that they're using Canvas with a custom onPaint implementation. You could do the same in your port, or, you can find an alternative, e.g. Shape with ShapePath, etc. These efforts are non-trivial, and it boils down to the level of effort you wish to invest.

How to get started with drawing robot

I am a beginner to robotics, and I wanted to program a robot arm to draw a picture on arbitrary objects I present to him.
I do have an Intel Realsense camera, will receive a dobot.cc robot arm next days, and thought about using ROS as a base, moveit for movements and the PCL library for object detection.
How do I connect all of these together? Are there any particulary interesting tutorials that you would recommend? Anything I should try out up front?
Also, I suppose I will need to build custom code for detecting the target object in the point cloud and calculate how the picture should be placed on the object and then use moveit to follow the target path. Where would this code go?
Any help would be appreciated.
Thanks,
Gregor
Meanwhile, I found an excellent book on the topic:
http://www.amazon.de/Learning-ROS-Robotics-Programming-Second/dp/B00YSIL6VM/

Qt OpenGLScene working example

I'm using an OpenGLScene as a wrapper of the openGL, and I've started with the most simple example of that I've found on the internet. I've just copied everything from the link where they have a zip.
I compiled and run the program, and apparently this warning is always coming up (in the drawbackground method):
if (painter->paintEngine()->type()
!= QPaintEngine::OpenGL) {
qWarning("OpenGLScene: drawBackground needs a "
"QGLWidget to be set as viewport on the "
"graphics view");
return;
Does anyone knows why (I'm on a Mac)? Does anyone has a more "stable" example? Is this warning relevant?
Basically, I would like to know why this warning is appearing, and how can I get rid of it...
I don't really know where to start. I've tried several simple things (making the QGLWidget current Context for instance), but I don't know enough Qt to understand the when and how is the drawbackground method called.
Qt OpenGLScene working example
"Boxes" demo in Qt 4. Launch qtdemo, select demonstration->boxes. Or read it all online. Either that or read documentation for overpainting, HelloGL or any other OpenGL example.
I'm trying to have a "wrapper" to OpenGL using Qt. Using Qt as GUI, and OpenGL as visualization
QGLWidget
Are you having OpenGL or OpenGL2?
Try this code
if (painter->paintEngine()->type() != QPaintEngine::OpenGL
|| painter->paintEngine()->type() != QPaintEngine::OpenGL2)
What are you trying to do ?
IIRC the qq26 example didn't work in 4.7 (haven't tested it in 4.8).
But overpainting QWidgets on top of an openGL scene was added to 4.8 ( http://qt-project.org/doc/qt-4.8/opengl-overpainting.html ) rather than the hack in that example
edit: Just using an opengl display in Qt is simple, just derive from a QWidget and implement initializeGL, resizeGL and paintGL. There are Qt functions to wrap textures, VBOs, PBOs and all the other opengl stuff. See the OpenGL examples in the distribution.
I've made a small minimal OpenGL+Qt which I think can answer the point:
I don't really know where to start. I've tried several simple things
(making the QGLWidget current Context for instance), but I don't know
enough Qt to understand the when and how is the drawbackground method
called.
I think it can help someone who was in the position I was when I asked this question.

Air native sound extension for IOS

Does anyone know of a sound library for IOS that has been ported to work with Air applications?
I was looking at his list: http://www.adobe.com/devnet/air/native-extensions-for-air.html and did not see anything related to sound but hoping I can find something out there thats not on the list.
Thanks
you can check this one: https://github.com/mateuszmackowiak/SoundExtension
This library enables you to control the default player (pause, play and others) and volume.
http://extensionsforair.com/
You can find the extensions here, if not available request one from 'em they will help.
Follow steps in this will be able to make your own pretty soon....
http://www.adobe.com/devnet/air/articles/transferring-data-ane-ios-pt1.html

graph component in GTK/Qt (like in blueJ)

I'm about to make a program (qt/gtk) where I need to display some kind of UML diagrams (like in BlueJ),
I wanted to ask you if there is such a component in GTK
It must work with new version of Gtk - gi.repository
The name of library is enough for me, I'll read docs, but if somebody post here some simple demo, it'll be appreciated.
Thank you
Dia (Old homepage) is a GTK based UML drawing tool. It is a very good tool with a lot of options. It is available on a number distros from their repositories. It has both application & library (libdia) components. There are python bindings available as well. If you have not checked it out, you should.
Hope this helps!
I found gaphas
You should checkout GooCanvas, I think is the more complete library for that kind of work.
I use python and pygtk, and use matplotlib to draw graphs in the GUI.
See a sample here : http://www.serpia.org/blog/2007/nov/03/matplotlib-and-pygtk-app/

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