The Crouch Mystery

[iHDeveloper]

A mystery that awaits us

It took about a week to figure out and solve the issue, probably @InventivetalentDev would have resolved it faster and quicker, but it was fun to solve for me. :)

Description

It appears that when the player sneaks/crouches in 1.19+. The glow around the player vanishes sadly.

Cause

After doing a deep investigation into NMS. I reached to this analysis provided in the picture below.

Analysis of outgoing packets from the server to the target (player)

It appears that when the player sneaks (crouches) a metadata packet is sent with the sneaking flag enabled (and without the glow flag enabled as expected). What's interesting here is that the sneaking flag is stored in the ENTITY_SHARED_FLAGS data watcher object. (are we expecting many entities being able to sneak? I don't really know. It will be fun to see though. lol)

This metadata packet is sent from an update players function that gets triggered from PlayerChunkMap tick method. The entity tracker gets called (by the update players function) and sends to the player the metadata packet of its new state.

Screenshots

• Player standing but glowing as well as other entities around him

• Player sneaking but glowing as well as other entities around him

Solution

We inject a packet handler using PacketListenerAPI to catch any metadata packet with the interested data watcher object (ENTITY_SHARED_FLAGS).

Then, we compare the glow data between the player who receives the packet and the entity thats the target of the glow flag in the metadata packet. We modify the packet when one of the parties are registered in the GlowAPI. If not, we just ignore the packet and proceed to listen to other packets.

Note: I added a map to register the entity unique id (UUID) by the entity id. It helps to avoid the async access to Bukkit/CraftBukkit APIs. And, it provides easy access in general. When the entity id is not found we just ignore modifying the packet in general.

Additional Fixes

• [92ca605] Looking for libraries without the craftbukkit prefix (only for 1.19+)
• [2fb5d58] Extending the class lookup to be used for 1.18+ versions.

Notes

• Is the issue reproducible on Minecraft 1.18.x?

References

• Glow goes away #126
• setGlowing() error in 1.18.2 #123
• Glow does not appear if receiver is not close to entity #128

[TherealB9B]

Also does this fix the glow vanishing with sprinting? Iirc it goes away while sprinting too and idk anything about github stuff so is this fix already in any jar file that works on 1.19.2?

[iHDeveloper]

Also does this fix the glow vanishing with sprinting? Iirc it goes away while sprinting too and idk anything about github stuff so is this fix already in any jar file that works on 1.19.2?

Picture the PR as installing a body guard that make sure that every party involved with GlowAPI has the right glow information. This body guard will ignore anything unrelated to GlowAPI. So, anything like spiriting or sneaking will not matter as much as long as this body guard is making sure the right glow information is given to the right players/entities.

Basically, it will also fix the sprinting issue. :)

[TherealB9B]

Also does this fix the glow vanishing with sprinting? Iirc it goes away while sprinting too and idk anything about github stuff so is this fix already in any jar file that works on 1.19.2?

Picture the PR as installing a body guard that make sure that every party involved with GlowAPI has the right glow information. This body guard will ignore anything unrelated to GlowAPI. So, anything like spiriting or sneaking will not matter as much as long as this body guard is making sure the right glow information is given to the right players/entities.

Basically, it will also fix the sprinting issue. :)

Great! But wdym with the first part?

[iHDeveloper]

Basically it makes sure that the correct glow information provided by the GlowAPI is already sent to the player

[TherealB9B]

Basically it makes sure that the correct glow information provided by the GlowAPI is already sent to the player

Ah okay. So will the fix be in the next update/jar of glowapi?

[iHDeveloper]

That I leave to Inventivetalent. She can review it whenever she wants. After all, she is the expert. No need for rushing :)

[TherealB9B]

That I leave to Inventivetalent. She can review it whenever she wants. After all, she is the expert. No need for rushing :)

Yeah I understand. Sorry if it sounded like I was rushing/pushing anyone btw. I was just curious haha

[iHDeveloper]

It's okay. I was just answering your question. If you have any about the PR, you can ask them here.

[iHDeveloper]

This PR will also solve the new issued issue #128 due to the solution being at the packet level (Supposing the entity will not show unless with a packet that shows it and a metadata that describes it).

Note: This is purely speculative analysis. I didn't give it a test. But, I will soon :)

[srnyx]

This PR will also solve the new issued issue #128 due to the solution being at the packet level (Supposing the entity will not show unless with a packet that shows it and a metadata that describes it).

Note: This is purely speculative analysis. I didn't give it a test. But, I will soon :)

Yep, looks to fixed, thank you! @InventivetalentDev

[srnyx]

Although... I think it broke color codes somehow (it only started doing this when I started using this GlowAPI PR):

[InventivetalentDev]

really nice PR, thank you! :)
I made a few more changes & merged your packet handling with the existing handler, the mystery seems to be solved though!

[InventivetalentDev]

@srnyx I don't see anything that would break color codes specifically, maybe there's something else interfering with it?
I'll also go ahead and redirect your thanks to @iHDeveloper, he put all the work into this! ^^