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Qt 5.2.1 QQuickFrameBufferObject: multisampling not working



  • Hello,

    I'm using a QQuickFramebufferObject and Renderer two draw custom graphics with OpenGL ES 2.0. I'm not able to switch to a newer Version of Qt!

    I have implemented my class based on the this Qt Blog article.

    My problem is, that I want to enable multisampling, but it isn't working. In the article they say multisampling can be enabled by setting the sample counter in QOpenGLFramebufferObjectFormat greater than zero:

    Finally, it is worth noting that QQuickFramebufferObject is also prepared to handle multisampling and screen changes.
    Whenever the QOpenGLFramebufferObject returned from createFramebufferObject() has multisampling enabled (the QOpenGLFramebufferObjectFormat has a sample count greater than 0 and multisampled framebuffers are supported by the OpenGL implementation in use), the samples will be resolved with a glBlitFramebuffer call into a non-multisampled FBO after each invocation of render(). This is done transparently to the applications so they do not have to worry about it."

    Finally I know that multisampling is working, because I also draw some stuff with the QQuickPainter and this graphic is multisampled.
    I have the same result if I run my programm for the embedded linux target or my linux working machine.

    Thanks for your help in advance!

    Best regards
    Heiko



  • Hello,

    no ideas?
    Do you need a minimal project from me?

    Best regards
    Heiko


  • Lifetime Qt Champion

    Hi,

    Yes, a minimal compilable project would be good. Unless people hit the same problem as you, recreating the same setup is not easy. You should also provide your Qt version and OS