[1.14.4] Unable to set Y motion

[-fr0st-]

Hello mod-makers.

I am trying to create a pair of boots that make the player bounce upon falling while wearing them. So I have this item class that does nothing special apart from extending ArmorItem, and a PlayerEvent class that does the following:

 

@Mod.EventBusSubscriber(modid = PegasusVanguard.ID)
public class ModPlayerEvents {

	@SubscribeEvent
	public static void onPlayerFall(LivingFallEvent event) {
		LivingEntity entity = event.getEntityLiving();

		if (entity instanceof PlayerEntity && !entity.getEntityWorld().isRemote) {
			Iterator<ItemStack> armorSlots = entity.getArmorInventoryList().iterator();
			entity = (PlayerEntity) entity;

			while (armorSlots.hasNext()) {
				if (armorSlots.next().getItem() instanceof ItemAirForceBoots) {
					event.setDamageMultiplier(0);
					entity.setFire(1); // why not
					
					Vec3d v = entity.getMotion();
					entity.setMotion(v.x, -v.y * 5.0D, v.z);
					entity.setJumping(true);
					entity.isAirBorne = true;
				}
			}
		}
	}
}

 

The only problem is setting the Y motion yields no result. First thing I tried is copying vanilla SlimeBlock code, but that didn't work. Then I played around with setMotion, setVelocity and travel, but I only managed to modify the X and Z components of the motion vector (and it works). I also tried, as you can see, to set some boolean flags to no avail. I am out of ideas at this point, the event fires just fine and code above setMotion is perfectly working. I don't see why just the Y axis is problematic...

Hoping someone can help out! Cheers!

[Differentiation]

4 hours ago, -fr0st- said:

Hello mod-makers.

I am trying to create a pair of boots that make the player bounce upon falling while wearing them. So I have this item class that does nothing special apart from extending ArmorItem, and a PlayerEvent class that does the following:

 

@Mod.EventBusSubscriber(modid = PegasusVanguard.ID)
public class ModPlayerEvents {

	@SubscribeEvent
	public static void onPlayerFall(LivingFallEvent event) {
		LivingEntity entity = event.getEntityLiving();

		if (entity instanceof PlayerEntity && !entity.getEntityWorld().isRemote) {
			Iterator<ItemStack> armorSlots = entity.getArmorInventoryList().iterator();
			entity = (PlayerEntity) entity;

			while (armorSlots.hasNext()) {
				if (armorSlots.next().getItem() instanceof ItemAirForceBoots) {
					event.setDamageMultiplier(0);
					entity.setFire(1); // why not
					
					Vec3d v = entity.getMotion();
					entity.setMotion(v.x, -v.y * 5.0D, v.z);
					entity.setJumping(true);
					entity.isAirBorne = true;
				}
			}
		}
	}
}

 

The only problem is setting the Y motion yields no result. First thing I tried is copying vanilla SlimeBlock code, but that didn't work. Then I played around with setMotion, setVelocity and travel, but I only managed to modify the X and Z components of the motion vector (and it works). I also tried, as you can see, to set some boolean flags to no avail. I am out of ideas at this point, the event fires just fine and code above setMotion is perfectly working. I don't see why just the Y axis is problematic...

Hoping someone can help out! Cheers!

Okay, motions and velocity have to be handled on the client side as well. The reason why nothing happens is because you have !World#isRemote check; only the server is notified of the velocity change, the client is not, so you won't witness anything happening.

 

Also, use PlayerEntity###getItemStackFromSlot to check if the boots are equipped.

 

Lastly, you don't need to include your Mod ID in the EventBusSubscriber annotation.

 

P.S. was the Entity#world field removed? If not, just use PlayerEntity#world instead of PlayerEntity###getEntityWorld.

Edited October 18, 2019 by Differentiation

[-fr0st-]

Hey! Thanks for the reply.

I have removed the check for client side and now it... sort of works.

The problem is that it works as long as i remove event.setDamageMultiplier(0), otherwise it just behaves as before.

This is certainly not good, because I also want to be able to avoid fall damage entirely. There might be some workaround (like using potion effects or something?) but I want it to be as elegant as possible. I just don't get why it interferes like that. Thanks for everything else, though.

 

For some reason it works if i set the damage multiplier to something really small, like 0.0001F. Another thing i noticed is that if I press the spacebar in midair, then the bounce effect will not trigger, otherwise it works (90%). Might be due to some boolean flags being set?

Edited October 18, 2019 by -fr0st-

[salvestrom]

1 hour ago, -fr0st- said:

it works as long as i remove event.setDamageMultiplier(0), otherwise it just behaves as before.

The damage multiplier is used directly on the fall distance, not the damage that you took from falling. Therefore, multiplying it by zero reduces your fall distance to 0. Which, I assume, is setting your Y motion to 0. Afraid I can't help with the space bar issue.

[Differentiation]

2 hours ago, -fr0st- said:

Hey! Thanks for the reply.

I have removed the check for client side and now it... sort of works.

The problem is that it works as long as i remove event.setDamageMultiplier(0), otherwise it just behaves as before.

This is certainly not good, because I also want to be able to avoid fall damage entirely. There might be some workaround (like using potion effects or something?) but I want it to be as elegant as possible. I just don't get why it interferes like that. Thanks for everything else, though.

 

For some reason it works if i set the damage multiplier to something really small, like 0.0001F. Another thing i noticed is that if I press the spacebar in midair, then the bounce effect will not trigger, otherwise it works (90%). Might be due to some boolean flags being set?

Simply cancel the event after running all the code will cancel damaging the player. HOWEVER, make sure to set event priority to low or lowest not to conflict with aspects/effects of other mods.

[-fr0st-]

13 hours ago, Differentiation said:

Simply cancel the event after running all the code will cancel damaging the player. HOWEVER, make sure to set event priority to low or lowest not to conflict with aspects/effects of other mods.

Hey!

I did as you instructed me, and I set the event priority to lowest.

I tried canceling the event but even doing so after running the rest of the code just yields the same result (player being set on fire and no movement).

[Animefan8888]

8 hours ago, -fr0st- said:

Hey!

Here is what you should do instead. Set the multiplier to 0. Check if the world is on the server (isRemote is false). Then modify the velocity/motion. Then do living.velocityChanged = true.

[-fr0st-]

15 hours ago, Animefan8888 said:

Here is what you should do instead. Set the multiplier to 0. Check if the world is on the server (isRemote is false). Then modify the velocity/motion. Then do living.velocityChanged = true.

Ahh yes, this is exactly what I was looking for! Thanks

[DavidM]

On 10/19/2019 at 2:22 AM, Differentiation said:

Lastly, you don't need to include your Mod ID in the EventBusSubscriber annotation.

You do have to include it unless the annotation is attached to a class inside the main mod class (which would have the mod ID passed in as a parameter in the @Mod annotation), which is not the case here.