>Psychtoolbox>PsychGLImageProcessing

Change parameters for drawing of frame-sequential stereo blue line sync lines for shutter glasses (stereo goggles).

SetStereoBlueLineSyncParameters(win [, vPos=max][, hFraction=0.25][, lineColor=[1,1,1]])

Call this function after the win = Screen(‘OpenWindow’,…); call on an
onscreen window in frame-sequential stereo mode to change the parameters
of drawing of stereo sync lines, as needed by stereo goggles or shutter
glasses like, e.g., CrystalEyes glasses. Enable automatic sync lines if
they aren’t enabled already. Sync lines are auto-enabled on ancient OSX
in stereomode 1, all systems in stereomode 11, and whenever automatic
fallback from stereomode 1 to 11 happens if a given gpu or OS does not
support stereomode 1, e.g., all OSX systems since 10.11 or so.

All parameters except the onscreen ‘win’dowhandle are optional and have
reasonable builtin defaults:

‘vPos’: Vertical position of the sync line: Default to windowheight - 1.
As a workaround for various broken graphics drivers, since October 2017
Psychtoolbox draws sync lines which are 3 scanlines high, from vPos to
vPos + 2, instead of a single line at vPos. This should make blue line
sync more robust against slight misplacement by buggy graphics drivers.

‘hFraction’: Sync lines for left eye view are drawn starting on the left
border with a length of hFraction * windowWidth. Right eye lines are
drawn with a length of (1-hFraction) * windowWidth.

The default of 0.25 should be ok for at least CrystalEyes goggles

‘lineColor’ intensity of the color channels for drawing the line in range
zero to one: Default is [1,1,1] = max red, green and blue –> A white
sync line. A setting of [0,0,1] = red off, green off, blue max would
create a classic blue sync line. However, some CrystalEyes stereoenablers
had problems detecting the signal this way, so we default to all-white.