As for differentiating between (non-ANGLE) OpenGL implementations, it's more tricky since there's no difference from Qt's point of view. However, you can still query strings like GL_RENDERER and look for "llvmpipe".

The example qtbase/examples/opengl/contextinfo may be a useful tool and reference for doing such checks.

@
#include <QApplication>
#include <QOpenGLWidget>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
a.setAttribute(Qt::AA_UseDesktopOpenGL);

QSurfaceFormat fmt;
fmt.setDepthBufferSize(24);
fmt.setVersion(3, 2);
fmt.setProfile(QSurfaceFormat::CoreProfile);

QSurfaceFormat::setDefaultFormat(fmt);

bool test = a.testAttribute(Qt::AA_UseDesktopOpenGL);
QOpenGLWidget w;
w.show();

return a.exec();
}@

play with commenting , uncommenting the line with setAttribute, test give tru if the line is uncommented, false if is commented, as expected.

@QCoreApplication a(argc,argv);//in main

bool test = a.testAttribute(Qt::AA_UseDesktopOpenGL);

//or somewhere else in the code:
bool test = qApp->testAttribute(Qt::AA_UseDesktopOpenGL);
@