Built on Bestsoft100's Base Shader v3.0 so that it looks like Vanilla.
Overlays a square cut-out on the Sun when the Moon is overlapping it. Also culls stars near the Sun/Moon so that they don't appear in front. Originally intended as a companion shader for the Ardwick data pack, but works generally.
CC0 licensed so please use this however you like.
Only works nicely for resource packs that have square Moons. ECLIPSE_BODY_HALFWIDTH controls the size of the cut-out, set to 2.85 for the Vanilla Moon size. See the Ardwick data pack's sun.png if you wish to shrink the Sun to be the same size as the Moon so that a full eclipse is possible (as the Vanilla resource pack ships a Moon that is smaller than the Sun).
Tested in 26.3 but its so light touch that it should work for 1.21+. If you want to check out eclipses try this shader with the Ardwick data pack and /time set 150000.
Other:
- Added Panini Projection. Off by default, customisable in settings.