[MC-161150] Low light emitting full blocks darken shadows around on low brightness settings

I don't think the light is supposed to look like this.

Affected blocks:

Respawn anchor (1, 2 or 3 charges)
Redstone ore (when lit)
Crying obsidian
Furnace (when lit, very subtly yellow)
Blast Furnace (when lit, very subtly yellow)
Smoker (when lit, very subtly yellow)

Linked issues

Attachments

Minecraft 26.1 Snapshot 5 - Singleplayer 28_01_2026 02_03_13.png

Comments 18

slicedlime 2019-09-26T07:20:18Z

I cannot reproduce this on 1.14.4 or 19w38b. What is required for this to happen? Is it only a problem in certain lighting conditions?

muzikbike 2019-09-26T08:56:04Z

I'll check more thoroughly when I get home but the world is a custom superflat with white concrete roughly within the y=20-30 range and created in the early 1.14 snapshots. If I can't reproduce this on other worlds I'll upload the world file (assuming it isn't too big).

muzikbike 2019-09-26T20:59:59Z

Can reproduce on a freshly created superflat world with the following preset:

minecraft:bedrock,20*minecraft:dirt,minecraft:white_concrete;minecraft:the_void;village

Brightness at or close to Moody.

Michael Wobst 2019-09-26T21:08:43Z

Yep. Can be reproduced quite easy with the aforementioned reproduction steps.

slicedlime 2019-09-27T08:16:12Z

Great, thank you!

8 more comments

pulpetti 2020-07-13T17:48:45Z

Also affects 1.16.1

muzikbike 2020-07-13T19:18:57Z

no prob

GeForceLegend 2020-11-12T11:25:42Z

This is caused by ambient occlusion of emitting opaque blocks are achieved by modifing smoothed skylight. This can be easily seen when loading with Optifine and a shaderpack. Lots of shader features uses skylight, for example, puddles in rainy weather. You can see there is no puddles near these blocks.
And for emitting opaque blocks with light level less than 14, their ambient occlusion seems also modify smoothed block light map. Smoothed block light of pixels near them can even drop to 1 (since this is smoothed light map in rendering, the light value in F3 screen is normal).

Avoma 2021-02-13T14:36:33Z

Can confirm in 21w06a.

Avoma 2021-03-01T12:54:01Z

Can confirm in 1.16.5 and 21w08b.

migrated 2021-04-17T15:28:16Z

Can confirm in 21w15a.

bodakugga 2022-03-15T15:12:14Z

Could this be fixed by simply making light emitting blocks NOT cast shadows onto other blocks? That was their behavior in versions from beta 1.3 (smooth lighting added) to beta 1.7.3, and got broken in beta 1.8, when the lighting engine was changed.

Avoma 2022-05-31T13:40:52Z

Can confirm in 1.18.2 and 1.19 Pre-release 4.

Avoma 2022-11-14T17:40:19Z

Can confirm in 1.19.2.

Maximus_3069 2026-01-28T05:04:11Z

Can confirm in 26.1 snapshot 5

Smooth lightning: ON

Maximus_3069 2026-02-03T19:16:44Z

Can confirm in 26.1 snapshot 6

GeForceLegend 2026-04-29T08:42:12Z

Looks like it was fixed in certain snapshot of 26.1. Smoothed sky light level around most opaque light sources is no longer reduced.

GeForceLegend 2026-04-29T08:50:58Z