tsubaki/FollowTargetSystem.cs

## FollowTargetSystem.cs
using Unity.Entities;
using Unity.Jobs;
using Unity.Collections;
using Unity.Burst;
using Unity.Transforms;
using Unity.Mathematics;
using UnityEngine;

public class FollowTargetSystem : JobComponentSystem
{
    protected override JobHandle OnUpdate(JobHandle inputDeps)
    {
        inputDeps = new LookTargetJob {
            deltaTime = Time.deltaTime,
            positionFromEntity = GetComponentDataFromEntity<Position>(true)
        }.Schedule(this, inputDeps);

        return inputDeps;
    }

    [BurstCompile]
    private struct LookTargetJob : IJobProcessComponentData<Target, Position>
    {
        [ReadOnly] public ComponentDataFromEntity<Position> positionFromEntity;
        public float deltaTime;

        public void Execute([ReadOnly] ref Target target, ref Position pos)
        {
            if (!positionFromEntity.Exists(target.Value))
                return;

            var targetPos = positionFromEntity[target.Value];
            var diff = targetPos.Value - pos.Value;
            diff = math.normalize(diff);
            pos.Value += diff * deltaTime;
        }
    }
}
	using Unity.Entities;
	using Unity.Jobs;
	using Unity.Collections;
	using Unity.Burst;
	using Unity.Transforms;
	using Unity.Mathematics;
	using UnityEngine;

	public class FollowTargetSystem : JobComponentSystem
	{
	protected override JobHandle OnUpdate(JobHandle inputDeps)
	{
	inputDeps = new LookTargetJob {
	deltaTime = Time.deltaTime,
	positionFromEntity = GetComponentDataFromEntity<Position>(true)
	}.Schedule(this, inputDeps);

	return inputDeps;
	}

	[BurstCompile]
	private struct LookTargetJob : IJobProcessComponentData<Target, Position>
	{
	[ReadOnly] public ComponentDataFromEntity<Position> positionFromEntity;
	public float deltaTime;

	public void Execute([ReadOnly] ref Target target, ref Position pos)
	{
	if (!positionFromEntity.Exists(target.Value))
	return;

	var targetPos = positionFromEntity[target.Value];
	var diff = targetPos.Value - pos.Value;
	diff = math.normalize(diff);
	pos.Value += diff * deltaTime;
	}
	}
	}