[Qt-interest] a bug in QGraphicsScene

[Yifei Li]

Bug description:

Shapes/texts drawn using QPainterPath may not be displayed correctly if GL_DEPTH_TEST is enabled in OpenGL

To reproduce:
Do OpenGL rendering in QGraphicsScene::drawBackground with depth test enabled, and then Qt 2D painting in QGraphicsScene::drawForeground()

Platform and Qt version:
Qt4.6.2: this problem happened to me on Windows 7(from time to time) and MacOS(all the time). 

Qt4.5: I haven't had the problem with the same code on Windows XP.

Yifei