As Game Developer known on Reddit as hoahluke explained, the LEDs are controlled by a WLED controller. They wrote a script to cycle through all 2,000 LEDs, lighting them one at a time while a laptop webcam captured a photo of each. This process was repeated from four different angles, and the resulting images were processed using NumPy and OpenCV to generate a rough 3D map of the lights.
"For any lights which were not visible, I just interpolated the positions between their nearest known neighbours – this worked quite well to fix the positioning of a lot of missed lights!", commented hoahluke.
If you want to feel some festive vibes, check out this adorable French supermarket ad that's gone viral recently:
