Hi, I have pushed the following WIP patch for review:
https://codereview.qt-project.org/#change,30554 The idea of this is to provide a set of classes that expose the OpenGL functions specific to the version and profile of the corresponding QOpenGLContext. This means that it is no longer necessary to use GLEW or similar or to manually resolve OpenGL entry points by hand. This allows developers using these classes to get per-context entry points easily and to also get compiler errors rather than runtime errors if they try to use a function not supported by that {version, profile} of OpenGL. The set of QOpenGLFunctions_<Major>_<Minor>_<Profile> classes are generated directly from the official OpenGL spec files as published by the Khronos group. As such we could potentially make the generation of these classes part of the qtbase bootstrap process. This would require importing the OpenGL spec files into the qtbase repo along with the code generator. The current WIP patch exposes the version specific functions via QOpenGLContext::versionFunctions() at present as there already exists a function QOpenGLContext::functions() which returns a pointer to a QOpenGLFunctions object. QOpenGLFunctions provides basically the same as the new classes but for the common subset of Desktop OpenGL 2 and OpenGL ES 2 as this is what is required by Qt itself (e.g. in QQ2). Another motivation for these new classes is that the existing QOpenGLFunctions is not enough to support modern OpenGL on the desktop. It cannot answer questions such as "are geometry shaders supported?". Geometry shaders are available in Qt4's QGLShaderProgram but are disabled in Qt 5's QOpenGLShaderProgram at present. If we combine these proposed classes with the extension resolved (which should be improved and made public) then we would able to easily check for support (either as a core feature or via an extension) and also be able to easily get access to resolved function entry points in the implementation. It would be a fairly simple job to extend the code generator to create classes for OpenGL extensions too (they are also in the spec files). I am currently thinking that the extension matcher can be used to query the available extensions and then as a factory to a family of classes that each represent one extension. I would like to seek opinion on whether people are happy with this general approach and how it should be placed in relation to the existing QOpenGLFunctions::functions(). Alongside it? Replace it? I do worry about the number of added symbols to QtGui though - OpenGL is not a small API. Perhaps adding these classes as plugins would be a good idea? I believe that such a framework coupled with QWindow would make Qt5 an excellent platform for OpenGL development as it would allow us to develop additional OpenGL enabler classes easily e.g. QOpenGLVertexArrayObject. Comments/thoughts/flames? Cheers, Sean -- Dr Sean Harmer | sean.har...@kdab.com | Senior Software Engineer 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 _______________________________________________ Development mailing list Development@qt-project.org http://lists.qt-project.org/mailman/listinfo/development
