Custom skybox is weird

[slava110]

Hi. First of all, thank you for this awesome effect! It runs almost perfectly on my KDE system.
However, I cannot use custom skybox. It looks like this

Or this

Should I use some specific image format? Can you send skybox file which has been used in README demo? I'm not sure if this problem is related to VirtualBox so I'd like to test it. Thanks.
P.s.: Skybox files I've used:

[zzag]

iirc skyboxes with .EXR file format exhibit that kind of visual artifacts, no idea why. Try .hdr

[slava110]

iirc skyboxes with .EXR file format exhibit that kind of visual artifacts, no idea why. Try .hdr

Oh, so there is a specific format for skybox! I've tried to use png and jpg, not some special formats like exr or hdr
Yeah, hdr format works perfectly, thanks!
Could you mention allowed formats somewhere tho (in Cube Settings if possible)? I think it's not very clear what formats should be used for skyboxes
Also it's a bit blurry but this problem is already covered by #2 so I'll just subsribe to that issue