[MC-90191] Armorstands, silverfish and endermites in boats spin rapidly

Expectation: Armor stand would just chill in the back.
Reality: https://www.youtube.com/watch?v=a617KVNG-LI

No, I did not have a teleport command running to rotate it or anything. Yes, this world was created in the version used.

Steps to reproduce are in the video, but also below

/summon Boat ~ ~ ~ {Passengers:[{id:"Skeleton"},{id:"ArmorStand"}]}

Armor Stands only start to spin once the boat is rotated. The more the boat is rotated from the south direction, the more it spins, plus the more you wait, the faster it spins. It seems to just rapidly switch from south to its correct rotation. Something about the armor stand's direction not correctly updating according to the boat's rotation.

Code analysis by @unknown can be found in this comment.

Linked issues

is duplicated by 3

MC-93280 ArmorStands on a boat continually turn on themselfs. Resolved

MC-96242 Armor Stand super twitch when in boat Resolved

MC-100176 Armor Stands in Boats going absolute shitnuts Resolved

relates to 1

MC-92962 ArmorStand rotating boat client side Resolved

Comments 26

marcono1234 2015-10-09T15:27:13Z

Confirmed for

15w41b When you ride the boat with an ArmorStand as second passenger and then dismount, the boat spins.

[Mod] redstonehelper 2015-10-15T18:45:41Z

Marcono1234: You're thinking of MC-90148.

kumasasa 2015-10-15T18:46:07Z

@unknown: You mean MC-90148

marcono1234 2015-10-21T15:22:35Z

No I was really talking about the fact that the boat (not only the paddles) spins

dodo comododo 2015-10-21T15:29:27Z

How did you get the armour stand in the boat?

16 more comments

[Mod] redstonehelper 2015-10-21T15:50:34Z

@unknown: But this ticket is about the armor stand spinning. Create a new ticket if the boat is spinning for you.

shufboyardee 2015-11-18T21:12:17Z

Still in 47a. Would be nice if ticket included:

/summon Boat ~ ~ ~ {Passengers:[{id:"Skeleton"},{id:"ArmorStand"}]}

kumasasa 2015-11-18T21:19:08Z

Thanks, done.

Mike Dueck 2015-11-18T21:27:44Z

@dodo comododo
It's in the video. Hence why I wrote "steps to reproduce are in the video".

@Kumasasa
Thanks for adding it to the ticket.

Mike Dueck 2015-11-18T21:30:23Z

@Kumasasa
Could you maybe change the post to say:
"Steps to reproduce are in the video, but also below".

I can't edit anything on mobile.

[Mod]Les3awe 2016-01-24T17:47:17Z

Confirmed for 16w03a

marcono1234 2016-01-28T18:27:24Z

Cannot confirm fixed for 16w04a
Once you start moving with the boat, the ArmorStand starts spinning again

marcono1234 2016-01-28T19:02:39Z

Affects Silverfish and Endermites as well

shufboyardee 2016-02-03T23:02:04Z

Affects 16w05a.

Spake Miner 2016-02-09T14:39:06Z

Confirmed for 16w05b, but one thing; Armor Stands only start to spin once the boat is rotated. The more the boat is rotated from the south direction, the more it spins, plus the more you wait, the faster it spins. It seems to just rapidly switch from south to its correct rotation. Something about the armor stand's direction not correctly updating according to the boat's rotation.

shufboyardee 2016-02-15T21:01:09Z

Affects 16w07a.

shufboyardee 2016-02-16T18:12:40Z

Affects 16w07b.

Jonah Simm 2016-02-17T22:24:22Z

confirmed for 1.9 pre-1

shufboyardee 2016-02-18T19:29:11Z

Affects 1.9 Pre-Release 2.

19Spleen 2016-02-28T13:24:36Z

Confirmed for 1.9-pre4

waterced1 2016-03-17T19:49:21Z

Confirmed for 1.9

kumasasa 2016-03-17T19:53:00Z

@unknown made changes - 29/Feb/16 4:27 PM
Affects Version/s Minecraft 1.9

@unknown added a comment - 3 minutes ago
Confirmed for 1.9

Hm...

marcono1234 2016-03-29T14:54:36Z

Confirmed for

1.9.1-pre3

marcono1234 2016-03-29T15:00:59Z

Please link to this comment in the description

The following is based on decompiled version of Minecraft 1.9 using MCP 9.24 beta. All method and class names are the names used in the decompiled version.

In general it looks like this is caused by wrong values for the fields net.minecraft.entity.EntityLivingBase.prevRenderYawOffset and net.minecraft.entity.EntityLivingBase.renderYawOffset. As I am not very familiar with how the rendering exactly works the following is only an assumption and observation of what happens when you change something. The changes mentioned might only fix the symptoms of the bug, but not the bug itself.

ArmorStands

If net.minecraft.entity.item.EntityArmorStand.updateDistance(float, float) does not update the field net.minecraft.entity.EntityLivingBase.prevRenderYawOffset anymore, the method net.minecraft.entity.EntityLivingBase.onUpdate() adds 360f to it and no rendering bug occurs.

Silverfish and Endermites

The methods net.minecraft.entity.monster.EntitySilverfish.onUpdate() (Silverfish) and net.minecraft.entity.monster.EntityEndermite.onUpdate() (Endermite) set a value for the field net.minecraft.entity.EntityLivingBase.renderYawOffset. Removing this code prevents the rendering bug from occurring.

Shulkers

Shulkers are still not completely fixed because they rotate slightly while rotating a boat.

Preventing the methods net.minecraft.entity.monster.EntityShulker.onUpdate() and net.minecraft.entity.monster.EntityShulker.onLivingUpdate() from setting values for the fields net.minecraft.entity.EntityLivingBase.renderYawOffset and net.minecraft.entity.EntityLivingBase.prevRenderYawOffset prevents this bug from happening.

Keep in mind that these changes are no fix suggestions

shufboyardee 2016-05-11T05:02:20Z

Affects 1.9.4.

Jens Bergensten 2016-08-09T13:23:29Z

Thanks for the help Marcono1234, though I fixed it by making sure that the endermite/silverfish updates all rotations