ThinClientInputSystem.cs

using System;
using System.Diagnostics;
using Unity.Entities;
using Unity.NetCode;

namespace Samples.HelloNetcode
{
    // This system should only run in thin client worlds (and normal input handling only in normal client worlds)
    [UpdateInGroup(typeof(HelloNetcodeInputSystemGroup))]
    [WorldSystemFilter(WorldSystemFilterFlags.ThinClientSimulation)]
    public partial class ThinClientInputSystem : SystemBase
    {
        int m_FrameCount;
        uint m_WorldIndex;

        protected override void OnCreate()
        {
            RequireForUpdate<EnableThinClients>();
            RequireForUpdate<EnableSpawnPlayer>();
            RequireForUpdate<NetworkIdComponent>();

            // Give every thin client some randomness
            var rand = Unity.Mathematics.Random.CreateFromIndex((uint)Stopwatch.GetTimestamp());
            m_FrameCount = rand.NextInt(100);
            m_WorldIndex = UInt32.Parse(World.Name.Substring(World.Name.Length - 1));
        }

        protected override void OnUpdate()
        {
            // Check if the connection has no command target set yet, if not then create it (this is the dummy thin client player)
            if (SystemAPI.TryGetSingleton<CommandTargetComponent>(out var commandTarget) && commandTarget.targetEntity == Entity.Null)
                CreateThinClientPlayer();

            byte left, right, up, down, jump;
            left = right = up = down = jump = 0;

            // Move in a random direction
            var state = (int)(SystemAPI.Time.ElapsedTime+m_WorldIndex) % 4;
            switch (state)
            {
                case 0: left = 1; break;
                case 1: right = 1; break;
                case 2: up = 1; break;
                case 3: down = 1; break;
            }

            // Jump every 100th frame
            if (++m_FrameCount % 100 == 0)
            {
                jump = 1;
                m_FrameCount = 0;
            }

            // Thin clients do not spawn anything so there will be only one PlayerInput component
            foreach (var inputData in SystemAPI.Query<RefRW<CharacterControllerPlayerInput>>())
            {
                inputData.ValueRW = default;
                if (jump == 1)
                    inputData.ValueRW.Jump.Set();
                if (left == 1)
                    inputData.ValueRW.Movement.x -= 1;
                if (right == 1)
                    inputData.ValueRW.Movement.x += 1;
                if (down == 1)
                    inputData.ValueRW.Movement.y -= 1;
                if (up == 1)
                    inputData.ValueRW.Movement.y += 1;
            }
        }

        void CreateThinClientPlayer()
        {
            // Create dummy entity to store the thin clients inputs
            // When using IInputComponentData the entity will need the input component and its generated
            // buffer, the GhostOwnerComponent set up with the local connection ID and finally the
            // CommandTargetComponent needs to be manually set.
            var ent = EntityManager.CreateEntity();
            EntityManager.AddComponent<CharacterControllerPlayerInput>(ent);

            var connectionId = SystemAPI.GetSingleton<NetworkIdComponent>().Value;
            EntityManager.AddComponentData(ent, new GhostOwnerComponent() { NetworkId = connectionId });

            // NOTE: The buffer type might not be recognized in your IDE but it will be generated and Unity will recognize it
            EntityManager.AddComponent<HelloNetcodeSamples.Generated.CharacterControllerPlayerInputInputBufferData>(ent);

            // NOTE: The server also has to manually set the command target for the thin client player
            // even though auto command target is used on the player prefab (and normal clients), see
            // SpawnPlayerSystem.
            SystemAPI.SetSingleton(new CommandTargetComponent { targetEntity = ent });
        }
    }
}