Reply To: Calibrating with a mirror???

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#102076
Oliver Kreylos
Keymaster

That is not correct. Your projector does not need a mirroring option, and the Kinect does not have to be in any special orientation.

In principle, the entire sandbox calibration procedure (base plane equation, box corners, projection matrix) can be run with a mirrored projector. If the projector is your only display, you’ll have to be able to read the menu entries backwards, and have to collect box corners in lower-right, lower-left, upper-right, upper-left order, i.e., as a mirror image of the noted order, but other than that everything works.

I overlooked mirrored setups in the SARndbox application itself, meaning that nothing is displayed with a mirrored calibration (it’s a one-line insertion of glFrontFace(GL_CW) if anyone’s curious). I’ll fix that in the future, but for now the solutions are thus:

When using an Nvidia graphics card, the driver has the option to flip the image horizontally or vertically. Open nvidia-settings, go to “X Server Display Configuration,” find the screen associated with your projector, select it (if it isn’t already), and choose either “Reflect along X” or “Reflect along Y” from the “Orientation” drop-down menu. Then apply and confirm.

Alternatively, run
$ xrandr
in a terminal to get the list of video outputs on your computer. For example, I have:

DVI-I-2 connected 1600x1200+0+0
DVI-I-3 connected 2560x1600+1600+0

the first being my secondary monitor, and the second being my primary. Find your projector, for example by its resolution, note its output name (first column of xrandr’s output), and then flip it by
$ xrandr --output <output name> --reflect x

For example, to flip my secondary, I would
$ xrandr --output DVI-I-2 --reflect x

To undo the reflection, run
$ xrandr --output <output name> --reflect normal

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