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Thread: QPainter QPaintDevice and QOpenGLFrameBufferObject Possible Incompatibility

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    Feb 2018
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    Question QPainter QPaintDevice and QOpenGLFrameBufferObject Possible Incompatibility


    I am fairly new to QT development and so maybe not good at understanding documentation very well. I am using a QT5.7 and can see that QPainter needs a QPaintDevice for Initialization in one of the constructors which do not have QOpenGLFrameBufferObject specified in the list of "Inherited by" section of QPaintDevice. Same is reflected in the compilation and I get an error if I do so. Everything is as expected until here.

    But in the documentation of QOpenGLFrameBufferObject I can see a QPainter can be used to draw on this. Is there any other way to make it working with QPainter.

    A bit of task context:
    I am using a video and drawing some shaped over it to reflect my research data and for this I implemented QAbstractVideoSurface. The loading of the current frame converted to QPixMap or QImage becomes very slow and so I am trying options with hardware acceleration of OpenGL.

    First is it correct thing to try QOpenGL for this problem.
    Second if I am missing something in using QOpenGL extension of QT to make it work with QPainter.

    Any other hint to make things faster in realtime processing is appreciated.
    Last edited by gaurav.kumar; 13th February 2018 at 21:18.

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