[1.12.2] Smooth Velocity for Client-Side Entity

[Solitary_Knight]

I'm trying to add a feature to a mod (1.12.2 currently, and ideally 1.8.9 as well) which will allow me to spawn an entity (armor stand) and control its movement. For testing, I'm having the entity copy my movements, offset by x = 2. I need to do everything client-side because I want it to run on a server to which I don't have access. Here is a thread which I am running via a command. "player" is the command sender, "world" is Minecraft.getInstance().world, and "mil" is just the milliseconds between updates.

class EntityThread extends Thread {
	Entity player;
	int mil;
	World world;
	EntityThread(EntityPlayer player, World world, int mil) {
		this.player = player;
		this.mil = mil;
		this.world = world;
	}

	public void run() {
		if (this.world.isRemote == true) {
			TKRS.message("Not server side.");
		}
		double x = player.posX + 2;
		double y = player.posY;
		double z = player.posZ;
		double vx = player.motionX;
		double vy = player.motionY;
		double vz = player.motionZ;
		float yaw = player.rotationYaw;
		float pitch = player.rotationPitch;
		Entity entity = new net.minecraft.entity.item.EntityArmorStand(world, x, y, z);
		world.spawnEntity(entity);
		for (int i = 0; i < (int)(10000/mil); i++) {
			try {
				Thread.sleep(this.mil);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			
			x = player.posX + 2;
			y = player.posY;
			z = player.posZ;
			vx = player.motionX;
			vy = player.motionY;
			vz = player.motionZ;
			yaw = player.rotationYaw;
			pitch = player.rotationPitch;
			
			entity.setLocationAndAngles(x, y, z, yaw, pitch);
			entity.setVelocity(vx, vy, vz);
			entity.velocityChanged = true;
			world.updateEntity(entity);
		}
		world.removeEntity(entity);
	}
}

This works OK both in single-player and on a server, except that it is very jittery because the position is only updating 20 times per second, and the velocity does not update at all. If I provide a server world to the EntityThread (only possible in singleplayer), it is smooth with velocity updates, but lags behind my movements for some reason (client-side world doesn't lag, just jittery).

 

So my question is, how can I update the velocity for an entity spawned on client-side, without significant lag? I've tried looking up how to simulate clientbound packets from a non-existent server to update the velocity, but no luck so far.

Edited November 22, 2019 by Solitary_Knight

[Solitary_Knight]

• Maybe using a different thread is iffy, but it's working perfectly fine for me so far.
• I am spawning the entity client-side, so that statement isn't true. I can't interact with it, and that's fine, I just want to be able to control its visual movement, which I can do, just not smoothly.

I did get it able to be a little smoother by using .setLocationAndAngles() every tick, and .move() 5 times per tick, but a better solution would be appreciated.

[Solitary_Knight]

1 hour ago, diesieben07 said:

It's not iffy, it is broken. It will break. And in unpredictable and seemingly inexplicable and strange ways.

 

The entity will behave strangely and this is in general not an intended use. If you want something to be client-side only use something other than entities, such as particles.

If a thread is going to break, do you have a recommendation for an alternative way to get/set player/entity position ~100 times per second?

I need the object which I am moving to be an armor stand (so that I can put a block on its head). I assume there is no such thing as a particle armor stand?

[SerpentDagger]

9 hours ago, Solitary_Knight said:

so that I can put a block on its head

Perhaps you just want to render a block there instead? I'm not sure exactly what your intent here is, but that might be what you're looking for.

[Draco18s]

9 hours ago, Solitary_Knight said:

I need the object which I am moving to be an armor stand (so that I can put a block on its head)

You realize that this entity you've created on the client side basically is a ghost, right? Nothing you do will ever show up on any other client's view of what you're doing. Placing a block "on" the armor stand won't take that block out of your inventory, etc.

[Cadiboo]

What are you trying to achieve, from a player’s perspective?

[DavidM]

I think OP wants to create a visual effect of an armor stand. There is no need for interaction or synchronizing to other clients.

 

Entities are not meant to be used as client-side rendering techniques. Instead of spawning the entity in the client world, you should subscribe to RenderWorldLastEvent and manually render the armor stand there. One approach would be to create a static list of all the visual armor stand's data, and render ArmorStandEntity in RenderWorldLastEvent according to the list.

 

Then, instead of creating another thread to handle the updating, simply subscribe to ClientTickEvent and make a timer to determine when movements should be applied to the rendered armor stand.

[Solitary_Knight]

45 minutes ago, DavidM said:

I think OP wants to create a visual effect of an armor stand. There is no need for interaction or synchronizing to other clients.

 

Entities are not meant to be used as client-side rendering techniques. Instead of spawning the entity in the client world, you should subscribe to RenderWorldLastEvent and manually render the armor stand there. One approach would be to create a static list of all the visual armor stand's data, and render ArmorStandEntity in RenderWorldLastEvent according to the list.

 

Then, instead of creating another thread to handle the updating, simply subscribe to ClientTickEvent and make a timer to determine when movements should be applied to the rendered armor stand.

Yes, you are correct about what I am trying to do. Although I don't understand it completely yet, what you are suggesting sounds useful, and I'll try it. Thanks