startScreenCoordinatesSystem with updward == true messes up screenshots #3
Description
When rendering with startScreenCoordinatesSystem(true); screenshots are messed
up. Tested with sample in attached gist on qglviewer 2.4.0 on Qt 5.2 on Linux. PNG
screenshot with oversampling 4.0. oversampling triggers it more often.
attached one messed up screenshot should have two distinct quads one grey one black.
