[MC-124331] Redstone lamps do not show on maps

The Bug

Redstone lamps do not show up on maps. Instead, the block below them is displayed.

Steps To Reproduce

Place a large amount of redstone lamps:

/fill ~1 ~ ~1 ~9 ~ ~9 minecraft:redstone_lamp

Create a map.
Look at the filled map and take note of whether or not the redstone lamps are on the map.

Observed Behavior

Redstone lamps are not shown on maps.

Expected Behavior

Redstone lamps would be shown on maps.

Code Analysis

Code analysis by @unknown in this comment.

Linked issues

relates to 1

MCPE-112543 Redstone lamps don't show up on maps Open

Attachments

MC-124331.mp4

Comments 19

Oval 2018-09-15T00:26:22Z

Confirmed for 1.13.1.

[Mod] markderickson 2020-11-09T20:40:50Z

I can confirm in 20w45a.

Giovanni Lanzarote 2020-12-14T11:01:25Z

confirmed for snapshot 20w49a

Giovanni Lanzarote 2020-12-20T11:40:17Z

Still an issue in snapshot 20W51A

Giovanni Lanzarote 2021-01-20T16:37:17Z

Still an issue in snapshot 21w03a

9 more comments

Avoma 2021-02-08T09:55:50Z

Can confirm in 21w05b.

Avoma 2021-02-17T12:43:47Z

Can confirm in 21w06a.

Avoma 2021-05-03T13:55:09Z

Can confirm in 21w17a.

Avoma 2021-08-21T17:36:13Z

Can confirm in 1.17.1. Video attached.

Avoma 2021-10-14T12:59:37Z

I am able to confirm this behavior in 21w41a. Here are some extra details regarding this problem.

The Bug:

Redstone lamps are not shown on maps.

Steps to Reproduce:

Summon a large area of redstone lamps.

/fill ~1 ~ ~1 ~9 ~ ~9 minecraft:redstone_lamp

Obtain an empty map and use it.
Look at the filled map you now have and take note as to whether or not redstone lamps are shown on maps.

Observed Behavior:

Redstone lamps are not shown on maps.

Expected Behavior:

Redstone lamps would be shown on maps.

Avoma 2021-11-27T12:24:46Z

I can confirm this behavior in 1.18 Release Candidate 3.

Here's a code analysis of this issue. The following is based on a decompiled version of Minecraft 1.17.1 using MCP-Reborn.

net.minecraft.world.level.block.Blocks.java

public class Blocks {
   ...
   public static final Block REDSTONE_LAMP = register("redstone_lamp", new RedstoneLampBlock(BlockBehaviour.Properties.of(Material.BUILDABLE_GLASS).lightLevel(litBlockEmission(15)).strength(0.3F).sound(SoundType.GLASS).isValidSpawn(Blocks::always)));
   ...

net.minecraft.world.level.material.Material.java

public final class Material {
   ...
   public static final Material BUILDABLE_GLASS = (new Material.Builder(MaterialColor.NONE)).build();
   ...

If we look at the above classes, we can see that redstone lamps do not have a MaterialColor, so instead, they use the MaterialColor of Material.BUILDABLE_GLASS. The problem here is that Material.BUILDABLE_GLASS has a MaterialColor of NONE, meaning that redstone lamps cannot be seen on maps.

Avoma 2021-12-22T12:11:05Z

Can confirm in 1.18.1.

Avoma 2022-04-04T11:34:15Z

Can confirm in 1.18.2 and 22w13a.

Avoma 2022-06-19T13:42:58Z

Can confirm in 1.19 and 22w24a.

Avoma 2022-08-21T19:02:29Z

Can confirm in 1.19.2.

TomatoClownfish 2023-01-20T12:48:09Z

Can confirm in 23w03a.

BeeTeeKay 2024-07-07T23:25:16Z

Affects 1.21

Viradex 2024-07-08T03:06:56Z

Requesting ownership of this issue to continue adding affected versions for future snapshots and releases, as the reporter has been inactive since 2018.

crubleigh 2024-08-27T07:02:37Z

Maybe it's not intentional, however, this is actually a very useful feature because redstone lamps are unique in that they act like a solid block when powered, while still being transparent on a map. This can be very useful while working on redstone map displays, animations, etc. Additionally, it's the only map transparent block that will block daylight, so it's the only suitable material to use for map displays and map tech to reduce lighting updates on big piston monstrosities (as map displays tend to be). It's my opinion that this feature should remain as is.

Alternatively, if redstone lamps are to be given color on a map, it would be really neat if the powered and unpowered states had different colors, maybe off is transparent and on is colored.

Thanks