Version information

sodium-fabric-mc1.17.1-0.3.2+build.7

Expected Behavior

The area under this tree should darken smoothly as it progresses to the trunk.

Actual Behavior

Four brighter lines can be seen circling the trunk, which is completely illogical - the world and geometry do not indicate that these should be present at all.

Reproduction Steps

1. Build a setup similar to this tree over a floor where smooth lighting is easy to observe, such as white concrete. A 5x5 square above it should suffice, and a central trunk will help to accentuate these lines
2. Pain

Java version

16

CPU

4x Intel(R) Core(TM) i3-3240 CPU @ 3.40GHz

GPU

Intel(R) HD Graphics 2500

Additional information

lithium-fabric-mc1.17.1-0.7.4

I believe that this is due to how the shadows are rendered based on each vertex having a shadow value, so it cant be perfectly smooth, and will show the triangles if you look too closely. Maybe, increasing Smooth Shading if you haven't might allevieate the issue

It's not possible to fix this issue without radical changes to how lighting works (i.e. generating a light map texture which is UV mapped to geometry, rather than using per-vertex colors.) We are probably never going to implement that just due to how invasive it is.