[Qt5.1 beta] OpenGL, white screen

  • Hi !

    I am a complete beginner in OpenGL (Windows x64)

    I used this example from KDAB :

    The code is exactly the same, except a dynamic_cast on this line:
    @m_funcs = m_context->versionFunctions()@

    And whatever I do, I get a white window.

    A @m_funcs->glClearColor(0.0f, 0.0f, 0.0f, 1.0f)@

    is expected to show a black background, isn't it ? It's always a white background, nothing is displayed.

    I also tested with a OpenGL 3.3 context.
    My drivers are updated, there must be something I did not understand ...

    (sorry, my English must be deplorable)

    Thanks !

  • Hi Bilouse,

    you must perform some other calls in order to see something into the screen.

    @m_context->makeCurrent( this ); // Make sure you make the context current
    m_funcs->glClearColor(0.0f, 0.0f, 0.0f, 1.0f); // Specify the color that glClear(...) will use
    m_funcs->glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT ); // Actually, clear the window with the color mentioned above
    m_context->swapBuffers( this ); // Send the data to the window

    Edit: I recommend you to download the tesselation example at the bottom of the "5th Qt5.1 post at KDAB":http://www.kdab.com/opengl-in-qt-5-1-part-5/

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