>Psychtoolbox>PsychTests

FlipTimingWithRTBoxPhotoDiodeTest([configFile][, targetFolder][, usevulkan=0][, bpc=8][, useXR=0])

Test visual stimulus onset timing accuracy and visual stimulus onset
timestamping precision and robustness under varying loads, conditions and
modes of operation. This requires one of the supported external
measurement devices to provide the “ground truth” for true stimulus onset
times. Currently supported:

• UCST RTBox with its own photo-diode (p)
• VPixx Inc. DataPixx/ViewPixx/ProPixx (d)
• UBW32/Bitwhacker + UCST VideoSwitcher (b)
• UCST Videoswitcher + UCST RtBox or CRS Bits# emulated RtBox (v)
• Other TTL trigger timestamp emitting devices + UCST RtBox or CRS Bits#,
  e.g., the CRS-ColorCal2 used as a photo-diode. (p)

The script can also be used without external equipment (n) to just test
stimulus onset accuracy with only indirect test of timestamping.

This documentation is incomplete for now, good luck!

‘configFile’ Filename of benchmark configuration file. If none is specified,
the file fliptimingdefaultconfig.mat from the Psychtoolbox/PsychTests/TestConfigurations/
folder is used for some reasonable default testing setup.

‘targetFolder’ Target folder for result files. If none is specified, a reasonable
location is selected if that location exists and is writable, if that does not work,
a fallback location is selected, if that does not work, the users home directory is
selected. If a folder is specified, that folder is used if it is writable, otherwise
the users home directory is tried as target.

‘usevulkan’ If 1, try to use a Vulkan display backend instead of the
OpenGL display backend. See ‘help PsychVulkan’ for supported hardware +
operating system combinations and required setup.

‘bpc’ Request a specific output framebuffer color precision. Currently
supported are 8 for standard 8 bpc RGBA8 framebuffer, 10 bpc for RGB10A2,
and 16 bpc for a RGBA16F floating point framebuffer. Defaults to 8 bpc,
which is the only precision that is guaranteed to be supported on all
operating systems, graphics cards and displays.

‘useXR’ If 1, try to test timing on a supported VR/AR/MR/XR display via
PsychVRHMD(). Might be fiddly and low performance, but not impossible.

Mandatory variables in the config file, part of the struct variable ‘conf’

conf.Stereo = Stereomode to use.
conf.Priority = Realtime priority to use.
conf.DWMEnabled = 1,0,-1 = On, Off, Auto
conf.SetForegroundWindow = 1,0,-1 = On, Off, Auto
conf.VBLTimestampingMode = Mode of high-precision timestamping.
conf.CheckAsyncFlip = 0,1,2 = Off-Use sync flip, 1 = Use async flip, 2 = Use async flip with polling, 3 = Use async flip with Waituntilasyncflipcertain.

Per trial parameters for trial i:

conf.waitFramesSched(i) = Number of ifi’s to wait before onset in trial i.
conf.loadjitter(i) = Max. random cpu load jitter to apply in frame i.
conf.gpuLoad(i) = Number of rects to draw in frame i (GPU load)