The bug
Short:
A water or ice block in the air makes the daylight it lets through decrease with every block in negative y-direction, which is normally NOT a feature of daylight.
Long:
While building an ice farm in a mountains biome, I moved the platform to a certain height. To make sure that the ground beneath the platform was not too dark, I decided to create the platform out of (white stained) glass. Since the Block of water and the ice block are (partially) transparent, I thought, the daylight would reach the ground with a light level of about 12 (Ice and water reduce the light level by 2 or 3). Actually the light level on the ground went down to 6 (distance of 9 blocks to the next not water filled glass block in horizontal direction). After some trial and error, I found out, that the daylight (normally not height dependent) was changed to a height dependent normal light of light level 12, which is decreased by 1, every block downwards.
How to reproduce
Set the time to daytime:
/time set noonRun the following commands in an open area without moving:
/fill ~-3 ~-3 ~-3 ~3 ~12 ~3 stone hollow /fill ~-2 ~12 ~-2 ~2 ~12 ~2 ice→ ❌ Skylight decreases with altitude after passing through the ice
Linked issues
Attachments
Comments 6
Confirmed in 1.16.1 and 20w27a. Steps to reproduce:
Set the time to daytime:
/time set noonRun the following commands in an open area without moving:
/fill ~-3 ~-3 ~-3 ~3 ~12 ~3 stone hollow /fill ~-2 ~12 ~-2 ~2 ~12 ~2 ice→ ❌ Skylight decreases with altitude after passing through the ice
With MC-265585 having received a priority and assignee, we now have confirmation that this is an intended mechanic.
Not exactly, I believe. The intended behavior could be that it's only diffused by the single block the light passes through.
That report is about it not diffusing at all,even inside the barrier.
This is working as intended. According to the Minecraft wiki, water and ice diffuse sunlight. This means that after passing through water and ice, sunlight will act like ordinary light (like light from a torch) instead of going all the way down like it usually does.