[PySide] Is QOpenGLFunctions_3_3_Core supported in PySide2

[Tom Goddard]

I am trying to figure out whether PySide2 offers an API for desktop OpenGL, e.g. 3.3 core profile.  Currently I use PyOpenGL which is poorly maintained and would like to switch to using PySide2 OpenGL bindings if possible.  Here is the Qt documentation of QOpenGLFunctions_3_3_Core that I would like to use from PySide2.

	https://doc.qt.io/qt-5/qopenglfunctions-3-3-core.html <https://doc.qt.io/qt-5/qopenglfunctions-3-3-core.html>

Here are failed attempts.  I am using PySide 15.1 on macOS 10.15.

1) First the class is not in QtGui which is where the live in C++ Qt

	from PySide2.QtGui import QOpenGLFunctions_3_3_Core
	-> import error, no such name

2) But there is an undocumented QtOpenGLFunctions module that has it

	from PySide2.QtOpenGLFunctions import QOpenGLFunctions_3_3_Core as GL

and it contains the functions, e.g. GL.glClear but does not have the constants

	GL.GL_COLOR_BUFFER_BIT
	-> attribute error

dir(GL) -> shows only glXYZ functions not any GL_XYZ constants.

3) If I take my QOpenGLContext instance (that I currently use with PyOpenGL) qc and try to get the functions

	GL = qc.versionFunctions()

it gives a QAbstractOpenGLFunctions instance with no opengl methods

	GL.glClear
	-> attribute error

There is a PySide2 bug report about that from Feb 2019 with no resolution

	https://bugreports.qt.io/browse/PYSIDE-955 <https://bugreports.qt.io/browse/PYSIDE-955?jql=project%20=%20PYSIDE%20AND%20text%20~%20QOpenGLFunctions>

4) In PyQt5 approach 3 works

	GL = qc.versionFunctions()
	GL
	-> <PyQt5._QOpenGLFunctions_4_1_Core.QOpenGLFunctions_4_1_Core at 0x14e325730>

and this module has glClear and GL_COLOR_BUFFER_BIT, seems to have what is needed although I have not tried using it.

Thanks for shedding any light on the using the desktop OpenGL API from PySide2.

	Tom Goddard
	ChimeraX molecular visualization developer


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