Previously when a new QOpenGLFramebufferObject was bound, the
QOpenGLContextPrivate::qgl_current_fbo member was also updated to point
to this new object.
But if a user called QOpenGLFramebufferObject::bindDefault(),
qgl_current_fbo was not unset, meaning that if the FBO object would be
deleted at some point, qgl_current_fbo would be a dangling pointer.
This patch makes sure to clear the value of qgl_current_fbo when
bindDefault() is called. It is cleared, and not set to point to another
object because the default platform OpenGL FBO is not backed by a
QOpenGLFramebufferObject.
Task-number: QTBUG-56296
Change-Id: I68b53d8b446660accdf5841df3d168ee2f133a90
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>
cd1d114140