Drive or query latency tester for Oculus Rift DK2 device ‘oculusPtr’.
‘cmd’ is the command code:
0 = Get next test draw color from 0 - 255 as [r,g,b] vector.
1 = Get most recent latency test results in seconds as a 5 component vector
latency = LatencyRender: (seconds) Last time between render IMU sample
latency = LatencyTimewarp: (seconds) Last time between timewarp IMU sample
latency = LatencyPostPresent (seconds) Average time between Vsync and
latency = ErrorRender (seconds) Last error in render predicted scanout
latency = ErrorTimewarp (seconds) Last error in timewarp predicted
If ‘cmd’ can’t get executed, then an empty result  is returned.