Just Like Rays

Light emitted by blocks in vanilla Minecraft spreads in a simple pattern that ignores how light travels in a room. Just Like Rays replaces that spread with a ray-like model, so walls cast shadows and light follows lines through open space. The change applies to block light across the world, and the mod works on existing worlds as well as new ones.

The mod is client and server, so the server and every player need it. Its effect on the server side is described as small, and it saves nothing extra to the world file. The author notes that a shader pack cannot yet be disabled while the mod is active, and that stability in edge cases is still expected to have quirks. Players who try it are advised to back up their world or test it in a new one first.

The code is under the GNU General Public License v3.0 or later and is open source. Fabric is the only loader with files, and builds exist for 26.3 as well as the 1.20.1 and 1.21.x line, with 26.1 – 26.2 also covered. Snapshot builds are published. A Forge 1.20.1 setup through a compatibility layer is reported to work, though it is not a supported setup.