v 1.09 problems with STEREO/HMD modes

[rdotsch]

viz.displaymode(2560,1024) 
viz.go(viz.FULLSCREEN | viz.STEREO)

didn't work for me. I get the same results as when I don't use the viz.displaymode statement. When I set it to other values (1280,1024) or anything else, I either get the following error:

ERROR: Failed to set requested display mode

or it doesn't help.