Keep track of destroyed QOpenGLContexts in QOpenGLVertexArrayObject

QOpenGLVertexArrayObject saved the QOpenGLContext it was created in at
the point of QOpenGLVertexArrayObjectPrivate::create(), but didn't set
the saved context back to 0 in QOpenGLVertexArrayObjectPrivate::destroy().

The result was that the zero-pointer checks in the VAO destructor never
hit, and we ended up trying to make a destroyed QOpenGLContext current.

This bug was triggered by the QFontEngine having a limit of 4 concurrent
glyph caches, so when we created the fifth glyph cache we would remove
an earlier one, which destroyed its VOA, that referenced a QOpenGLContext
for a window that had been destroyed already.

We now reset the context back to 0, and disconnect aboutToBeDestroyed()
at the point of QOpenGLVertexArrayObjectPrivate::destroy().

Change-Id: Ib16f3877b310144886cf863b16697c137e7c7941
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

0 files changed, 0 insertions, 0 deletions