Very helpful, thanks! The in-build GDevelop cube map have so exotic and twisted coordinates, it's like build terrible on purpose lol. The set up with https://matheowis.github.io/HDRI-to-CubeMap/ is still far from perfect because I need to export bigger map 12288 x 2048, then cut it x6, and then resize each map to 512x512. If I export straight 512x512 from matheowis's tool, the result is jagged pixels.