[1.18.x] Chickens in MC are slower than players despite having higher speed stats? Why?

[Budschie]

Hello,

whilst experimenting with copying attribute maps from a chicken to a player, I stumbled across one peculiar little detail. When copying the movement speed attribute to the player, they become extremely fast. After looking at the code, I could indeed verify that the movement speed of the chicken is (in theory) indeed higher than the speed of the player - the chicken has a movement speed of 0.25D while the player only has a movement speed of 0.1F. I looked deeper in the code and could verify that the chicken's WaterAvoidingRandomStrollGoal has a speed modifier of 1.0D, which means that the movement of the chicken (0.25D) should in theory not be altered. This interesting behavior is not unique to the chicken though - it applies to pretty much every living entity as well.

So, this begs the question: Why? Why is the chicken in practice slower than the player?

For me, there are two possibilities: Either the player moves too fast for their speed value, or the chicken moves too slow. As of now, I could not verify either of those possibilities.

By the way, the reason why I even sought the solution of this issue is that I am currently in the process of creating a new version for my morph mod, and I would like to set the player's speed to the speed of the entity in which you're currently morphed into.

I'd be very grateful if someone could help me with this topic, as my expertise and trivia in regards to the code of Minecraft (as well as the hour that I spent trying to solve this issue) is evidently not enough to solve this mystery.

With kind regards,

- Budschie

[warjort]

Whenever I look at the movement code in Minecraft, it always makes my head hurt. 🙂

 

I can't give you a definite answer, but I think you want to look at how zza is changed in Mob.setSpeed() vs LocalPlayer.serverAiStep() and follow the rabbit hole.

Basically, it is setting the forward impulse to the speed for Mobs, but giving players a forward impulse of 1.0f when they hold the key down. See KeyboardInput.

The speed is used later in LivingEntity.handleRelativeFrictionAndCalculateMovement()

 

 

[warjort]

If you are planning on changing the base movement speed for players, you are probably going to have to look at how Abilities.walkingSpeed is used.

Edited September 9, 2022 by warjort