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    • UNSOLVED From QOpenGLContext to CGLContext
      General and Desktop • opengl cocoa • • Ulysse  

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    • SOLVED can't read values from QOpenGLFramebuffer 2nd color attachment
      General and Desktop • opengl qopenglframebuf fbo • • strattonbrazil  

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      I did in fact have to call glDrawBuffers myself. I assumed this was handled by the FBO binding, but apparently not. QOpenGLExtraFunctions* f = QOpenGLContext::currentContext()->extraFunctions(); GLenum bufs[2] = { GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1 }; f->glDrawBuffers(2, bufs); This seems strange to me that the FBO abstraction supports color attachments, but requires extra functions to use them.
    • SOLVED QOpenGLFramebufferObject renders only first frame
      QML and Qt Quick • opengl qtquick framebuffer • • Kyroaku  

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      'Client vertex and index arrays - all vertex array attribute and element array index pointers must refer to buffer objects. The default vertex array object (the name zero) is also deprecated. Calling VertexAttribPointer when no buffer object or no vertex array object is bound will generate an INVALID_- OPERATION error, as will calling any array drawing command when no vertex array object is bound.' source: https://www.khronos.org/registry/OpenGL/specs/gl/glspec33.core.pdf page 344
    • SOLVED How to use anti-aliasing on QGLWidget?
      General and Desktop • opengl qopenglwidget antialiasing qglwidge • • BoboFuego  

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      @BoboFuego said in How to use anti-aliasing on QGLWidget?: how can I add MyWidget.h as promoted class for it in the MainWindow constructor? Promoted class won't allow you to pass parameters to a constructor. Just don't add it in the designer at all. Lets say you've got this designer_widget as a central widget of the mian window in the designer. Just delete it entirely and add it in code: MainWindow::Mainwindow(QWidget* parent) : QMainWindow(parent) { ui->setupUi(this); MyWidget* gl_widget = new MyWidget(); setCentralWidget(gl_widget); }
    • UNSOLVED Window's content (OpenGL) freezes when interacting with its title bar - Bug?
      QML and Qt Quick • qml opengl window freezing • • IanShade  

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    • UNSOLVED Failure to find OpenGL and weird warnings in MSVC 2019
      General and Desktop • opengl qmake msvc2019 • • feistykittykat  

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      @feistykittykat Don't know if I'm allowed to bump this bad boy up. Been struggling to use PVRVFrame or something similar to get openGL found on my machine, but I have no idea how to set it up for QT. Still not even sure if that's the source of my problem.
    • SOLVED Using a label to display large images in QT GUI
      General and Desktop • opengl opencv qlabel image display pixmap • • rtavakko  

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      An update on this. It works perfectly and its a very low-cost solution. My processing time remains almost the same (~10mS) using this method since the painter does the scaling for you when it draws. Thanks for your help guys.
    • SOLVED qpainter performance
      General and Desktop • opengl qpainter performance • • dalishi  

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      @kent-dorfman Thanks and will try out those methods also.
    • SOLVED Spout / OpenGL GL_RGBA to QImage
      General and Desktop • opengl spout • • rtavakko  

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      Just to sum up this thread for anyone else having this issue, this would be the correct way to do it: QImage img; unsigned char* data; data = new unsigned char[4*width*height*sizeof(unsigned char)]; img = QImage((uchar*)(data),width,height,QImage::Format_RGBA8888); Make sure you allocate the appropriate space needed. E.g. if image format is RGB, size of the data array will be 3 * width * height * sizeof(unsigned char) and the QImage format will be QImage::Format_RGB888. Thanks all for your help.
    • UNSOLVED How to get vertices, normals and indeces from Qt3DRender::QAttribute buffer of Qt3DRender::QGeometry
      General and Desktop • opengl qt3d • • JulianM  

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      @julianm You will have to set setSyncData(true); on the attribute-buffers and also synch the index buffers to get the right vertices.
    • UNSOLVED Incorrect Position of viewport in OpenGL + Qt
      General and Desktop • opengl qopenglwidget • • sckorpio  

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      Hi and welcome to devnet, From the looks of it you are using both glu and the fixed pipeline. Since you are starting a new project, may a suggest taking a look at the Qt OpenGL examples and their use of current technologies like shaders ?
    • UNSOLVED QWindow - openGL implementation, painter not paiting?
      General and Desktop • opengl qwindow • • Dariusz  

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      Hi Hmm, nope. it looks very much like the sample with some code from TriangleWindow::initialize() in the render() function.
    • UNSOLVED Get context /Id of QOpenGLBuffer, data wont render - debuging help.
      General and Desktop • opengl qopengl • • Dariusz  

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    • SOLVED Displaying widgets on top of Opengl widget (Ogre engine)
      General and Desktop • opengl transparency ogre • • gabbsson  

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      @SGaist My solution is heavily inspired by: this old ogre wiki post (should have linked it as well, forgot about it until now). I mostly slimmed it down to what I posted as my solution, but I agree if I have time I'll try to make an example/entry. There are some things that need to be updated from the linked post to fit Ogre 2.1 since the post is old.
    • UNSOLVED How to convert voice to text with QOpenGL
      General and Desktop • c++ opengl qopengl speech voice recogniti • • HW-Developer  

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      @HW-Developer OK, I don't want to discourage you, maybe you just want to play with it, I've said I have no knowledge. But maybe if that sort of thing was freely available from 2005 there are some more recent ones which might be better?
    • UNSOLVED Draw a Ruler using QtOpenGL
      General and Desktop • opengl gui • • HW-Developer  

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      @kenchan I want to draw it on QOpenGLWidget and i want to relate it to an audio file so i can position it wherever i want
    • UNSOLVED Play an audio file in milliseconds
      General and Desktop • opengl qtmultimedia multimedia audio sfml • • HW-Developer  

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      https://drive.google.com/file/d/1SHw3k6gY9pz8cL7skhDUPUf2NrwF4xeE/view
    • UNSOLVED Draw a line with opengl using xml file
      General and Desktop • opengl gui xml qtopengl • • HW-Developer  

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      @HW-Developer Start here http://doc.qt.io/qt-5/qtxml-index.html
    • UNSOLVED Force QT QOpenGLWidget to use a particular graphics card
      General and Desktop • opengl qopenglwidget cuda • • oracle3001  

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    • UNSOLVED Nixie a vintage digital and virtual 3D clock
      Showcase • linux opengl windows raspberry pi 3 clocks • • ptstream  

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    • UNSOLVED QOpenGLFrameBufferObject for 3D Objects
      General and Desktop • opengl framebufferobje • • Ankit.Jain  

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      Off the top of my head, I am not sure if fbo::save() is valid while the FBO is still bound as the target for drawing. Try releasing it first and then calling save. An FBO can only be used as a texture when it is not bound as a target -- I think that applies to all readback operations. Also, you have a glClearColor, but you never glClear(). If there is garbage in the depth buffer of the FBO, maybe your stuff is never getting drawn. glClear() the depth buffer and the image buffer before you draw. At very least you should be able to see the clear color in the FBO when you save it, so you know the binding is working at that point.
    • SOLVED Simple 3d drawing
      Brainstorm • opengl example 3d canvas tesseract • • J.Hilk  

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      Alright, with much time and an extensive amout of google search I managed to cobble a working QOpenGLWidget program together. I used this official Qt-Example as a basline: http://doc.qt.io/qt-5/qtopengl-cube-example.html here is the combination with my Tesseract code https://github.com/DeiVadder/Tesseract-Challenge-OpenGL It's working, yeah me!!, but I have the feeling that it's far from ideal. I'm just glad I managed to draw something in 3d. Anyway, closed and solved.
    • UNSOLVED OpenGL context and testing with catch2
      General and Desktop • opengl test context • • BePie  

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    • SOLVED How to render graphics components in the separate classes in Qt OpenGL?
      General and Desktop • qt5 opengl qopenglwidget rendering graphics • • Eager  

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      @SGaist Thank you so much! Your response was much helpful!
    • UNSOLVED Cannot turn on overlay plane using OpenGL in Qt5
      General and Desktop • qt5 opengl visual studio • • MikeKit  

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      Before crossing that feature definitively, I'd recommend asking on the interest mailing list. You'll find there Qt's developers/maintainers. This forum is more user oriented.
    • UNSOLVED QPainter drawRect does not work with GL_CULL_FACE
      General and Desktop • opengl qpainter qopenglwidget • • dalishi  

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      @dalishi You should not mix painter and gl calls like that. You should put gl calls between calls to beginNativePainting() and endNativePainting(), which are painter functions. It might also help to save the painter state before and restore it after depending on how it messes up your gl stuff. the docs here tell you what the painter does to the states.
    • SOLVED Problem using QGraphicsVideoItem with QOpenGLWidget
      General and Desktop • opengl qtquick mac os graphcisview • • Ilja  

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      @Ilja Super good to hear. Thank you for the feedback. happy programming.
    • UNSOLVED QGraphicsView and QML: big image is not shown
      General and Desktop • qml opengl qgraphicsview • • KoenBr  

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      Hi and welcome to devnet, What version of Qt are you using ? On what OS ? Which architecture ? What type of image is that ?
    • UNSOLVED How pass an array from qml to opengl Shader
      QML and Qt Quick • qml opengl array gsl • • simkat82  

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    • UNSOLVED OpenGL Core Profile not supported on the current platform (Linux)
      QtWebEngine • opengl • • stefi610  

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    • UNSOLVED Frustrating Installation Process - Helpful hints for Windows 10?
      Tools • opengl windows 10 qt version • • PJM4B  

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      Hi, What version of Qt did you install ? What graphics card are you using ? Did you check whether you had up to date drivers ?
    • SOLVED How to set GL_LINEAR as default on QOpenGLFramebufferObject ?
      Mobile and Embedded • android opengl scale decoder hw acceleration • • delamor  

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      If found the way by myself, if this can help to someone, is a question of attaching the texture again and change it before the fbo generation. Like: ``` glBindTexture(GL_TEXTURE_2D, d->fbo->texture()); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); // Linear Filtering glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); // Linear Filtering
    • UNSOLVED Bad shader result in a custom QQuickItem
      QML and Qt Quick • qml opengl qtquick2 qquickitem scene graph • • seyed  

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      @seyed As I understand things, you need to get hold of the item's transform and do whatever your rendering needs to do with it for it to have effect... see https://stackoverflow.com/questions/28535528/how-can-i-get-transform-matrix-for-qquickitem . (Similarly, nothing will implement the opacity property for you... you have to bring it into your OpenGL code and use it in your fragment shader.)
    • UNSOLVED "Standard expectations" for a renderer
      General and Desktop • opengl qtquick coordinate • • BePie  

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    • UNSOLVED Displaying YUV buffer on a QWidget.
      General and Desktop • opengl qwidget yuv • • SilverSurfer  

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      Hi, IIRC, since 5.8 or 5.9, QtMultimedia has OpenGL (vertex/fragment shaders) support for that kind of format. You should take a look there.
    • UNSOLVED App crashes after changing window size
      General and Desktop • qml opengl qtquick • • Nikita_Dedov  

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      Hi, What graphic hardware are used on these machines ? Version of the driver ? Also note that 5.7 is outdated, you should consider updating to the current LTS which is Qt 5.9.4 or even 5.10
    • SOLVED Unable to run any QML app (QGLXContext issue)
      Installation and Deployment • qml linux opengl nvidia qglxcontext • • tansgumus  

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      I fixed this issue by my nvidia driver to recent version from this PPA ppa:graphics-drivers/ppa