Xlights 2026.12 sloooooow to render

[AAH]

I grabbed Xlights 2026.12 this morning as it had a few good things in it and a bunch of bug fixes. The bits that I tested out worked well but when I did a render to have a look at my changes the sequence that I was working on took 480s to render. A few quick changes and it took a further 480s to re-render. I rolled back to 2026.11 (which had issues with being able to expand groups etc) and the sequence rendered in 19s.
I've submitted a github bug report including the sequence I was working with.
The results may vary depending on your computer and OS but beware that there is the potential for an issue to be lurking that causes a 20:1 blowout in the rendering time.

 

[AAH]

There is a caveat to xlights 2026.12 rendering rather slow. It is 1 effect and 1 setting that causes it.
The setting was from a vendor sequence.
The setting is the "galaxy effect" and under options the "scale to buffer" checkbox works very well as a speed limiter
Xlights 2026.13 will have a new/old render style checkbox I'm told.
Fortunately the Xlights developers could isolate the exact cause which wouldn't have happened if I hadn't provided the sequence that caused the problem. It was a pre-2025 source sequence and the changes to xlights and the older sequence didn't play well together.