Different projection matrix per viewpoint

[dcnieho]

Hi Jeff,

I just realize that more is affected by the fact that viz.MainWindow refers to the auxiliary window on the desktop: calls to functions such as viz.MainWindow.worldToScreen() don't do the right thing either, returning values in desktop screen instead of HMD screen pixel-coordinates.

I hope there is some "he, dude, tell me about the HMD screen please" flag somewhere

All the best,
Dee