CubeSpawnSystem.cs

using Unity.Burst;
using Unity.Collections;
using Unity.Entities;
using Unity.Rendering;
using Unity.Transforms;

namespace HelloCube.StateChange
{
    public partial struct CubeSpawnSystem : ISystem
    {
        Config priorConfig;

        [BurstCompile]
        public void OnCreate(ref SystemState state)
        {
            state.RequireForUpdate<Config>();
            state.RequireForUpdate<ExecuteStateChange>();
        }

        [BurstCompile]
        public void OnUpdate(ref SystemState state)
        {
            var config = SystemAPI.GetSingleton<Config>();

            if (ConfigEquals(priorConfig, config))
            {
                return;
            }
            priorConfig = config;

            var query = SystemAPI.QueryBuilder().WithAll<URPMaterialPropertyBaseColor>().Build();
            state.EntityManager.DestroyEntity(query);

            var entities = state.EntityManager.Instantiate(
                config.Prefab,
                (int)(config.Size * config.Size),
                Allocator.Temp);

            var center = (config.Size - 1) / 2f;
            int i = 0;
            foreach (var transform in
                     SystemAPI.Query<RefRW<LocalTransform>>())
            {
                transform.ValueRW.Scale = 1;
                transform.ValueRW.Position.x = (i % config.Size - center) * 1.5f;
                transform.ValueRW.Position.z = (i / config.Size - center) * 1.5f;
                i++;
            }

            var spinQuery = SystemAPI.QueryBuilder().WithAll<Spin>().Build();

            if (config.Mode == Mode.VALUE)
            {
                state.EntityManager.AddComponent<Spin>(query);
            }
            else if (config.Mode == Mode.ENABLEABLE_COMPONENT)
            {
                state.EntityManager.AddComponent<Spin>(query);
                state.EntityManager.SetComponentEnabled<Spin>(spinQuery, false);
            }
        }

        bool ConfigEquals(Config c1, Config c2)
        {
            return c1.Size == c2.Size && c1.Radius == c2.Radius && c1.Mode == c2.Mode;
        }
    }
}