Also, QOpenGLFunctions doesn't have a glClear() function while being advertised as "The QOpenGLFunctions class provides cross-platform access to the OpenGL/ES 2.0 API" but GLES2.0 does have a glClear() function.
Is it a bug? Other classes like QOpenGLFunctions_2_1 and QOpenGLFunctions_3_2_Core do have such a function. On Fri, Aug 2, 2013 at 9:35 PM, Jiergir Ogoerg <[email protected]> wrote: > Thanks both of you, I see now, GL is old (1993 I guess) and it shows, e.g. > it requires creating a context on windows before even being able to query > GL info etc. > > What do you think of the new Linux GL ABI proposal from Nvidia: > https://github.com/aritger/linux-opengl-abi-proposal > > I recall doing some WebGL work a month ago (I forgot about) and I ran into > the same issue - couldn't use the same "gl" on multiple GL canvas on an > html5 page, > but in WebGL the function names are stripped of the "gl" prefix so you > don't have to repeat yourself like gl.glUseProgram, just gl.UseProgram - > with > Qt5 I'd have to use the former, unfortunately, but not a big deal. > > > > On Fri, Aug 2, 2013 at 3:21 PM, Sean Harmer <[email protected]> wrote: > >> Hi, >> >> On Friday 02 August 2013 15:01:05 Jiergir Ogoerg wrote: >> > Thanks, but it's better to use functions wrapped in namespaces when it's >> > possible (for example - according to Google's C++ coding style) instead >> of >> > static methods in classes or methods of class instances or any other >> > solution when you can just use functions wrapped in namespaces. >> > And no, Qt5 doesn't allow using glew. >> > >> > On your later point - could you please elaborate on why you need the GL >> > function addresses to be context-specific? I've used freeglut and GLFW >> > before and never cared of had issues with this. >> >> Please see: >> >> http://www.opengl.org/wiki/Load_OpenGL_Functions >> >> and >> >> >> http://msdn.microsoft.com/en-us/library/windows/desktop/dd374386(v=vs.85).aspx >> >> Cheers, >> >> Sean >> >> > >> > On Fri, Aug 2, 2013 at 1:44 PM, Sean Harmer <[email protected]> >> wrote: >> > > On Friday 02 August 2013 10:05:56 Sze Howe Koh wrote: >> > > > On 2 August 2013 08:16, Jiergir Ogoerg <[email protected]> wrote: >> > > > > Hi, >> > > > > I'm willing to switch to QT5 with GL, >> > > > > afaik in Qt5 the GL functions are encapsulated into a class that >> > > >> > > extends >> > > >> > > > > QAbstractOpenGLFunctions and you can't use the GL calls outside >> that >> > > >> > > class >> > > >> > > > > unless you pass each time a reference to this class. >> > > > > >> > > > > Why doesn't it publish the GL functions publicly (not inside a >> class >> > > > > instance) like glew and other tools do? >> > > > > >> > > > > I'm asking because I have a lib of mine that uses GL calls, what >> > > >> > > should I >> > > >> > > > > do, pass an instance of OpenGLFunctions class to each method in >> the >> > > >> > > lib? - >> > > >> > > > > that's cumbersome. >> > > > >> > > > Hi, >> > > > >> > > > To answer your second question, you could use a global pointer to a >> > > > QOpenGLFunctions_X object -- no need to pass it as around as an >> > > > argument. >> > > >> > > Or set it as a member variable in that class. Or inherit your class >> from >> > > QOpenGLFunctions_blah. Or you could resolve global functions >> yourself. Or >> > > maybe use GLEW - although I've not tried that with Qt for a while now. >> > > >> > > The reason we have these functions on a class rather than globally is >> that >> > > the >> > > function addresses can be context-specific. >> > > >> > > Cheers, >> > > >> > > Sean >> > > -- >> > > Join us in October at Qt Developer Days 2013 - >> https://devdays.kdab.com >> > > >> > > Dr Sean Harmer | [email protected] | Managing Director UK >> > > Klarälvdalens Datakonsult AB, a KDAB Group company >> > > Tel. Sweden (HQ) +46-563-540090, USA +1-866-777-KDAB(5322) >> > > KDAB - Qt Experts - Platform-independent software solutions >> -- >> Join us in October at Qt Developer Days 2013 - https://devdays.kdab.com >> >> Dr Sean Harmer | [email protected] | Managing Director UK >> Klarälvdalens Datakonsult AB, a KDAB Group company >> Tel. Sweden (HQ) +46-563-540090, USA +1-866-777-KDAB(5322) >> KDAB - Qt Experts - Platform-independent software solutions >> > >
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