Xvfb and number of bytes per pixel

[Marcin K]

It's not that easy. We have to make a fade out/in gradient on overlapping areas because it is not possible to align projectors pixel-peefect (there are also some lens errors like barrels etc). We're already using xrandr overlap with hardware edge blending.

> On 13 Sep 2020, at 05:49, Adam Nielsen <a.nielsen at shikadi.net> wrote:
> 
> 
>> 
>> The main issue is that we don't have enough (physical) space and budget ;)
>> to use bigger and more expensive projectors with edge blending, so I wrote
>> small piece of code for that (python + moderngl) which is grabbing pixel
>> data from xvfb to "project" it onto a big quad, then, setting viewports I'm
>> calculating edge masks for overlapping areas, and black levels for non
>> overlapping aras... etc.
> 
> Maybe I'm misunderstanding, but couldn't you just use xrandr to change
> the viewports for each output so that a few pixels near the edges
> overlap and get sent to multiple projectors?
> 
> Maybe the overlapping sections might become a bit brighter having the same
> pixels drawn by two projectors, but I guess you could just overlay a fixed
> rectangle in your code with the right alpha value to dim those pixels to
> compensate.
> 
> Cheers,
> Adam.