add basic README

.gitignore

@@ -8,4 +8,6 @@ build/
 
 .vscode
 
-imgui.ini
+imgui.ini
+
+test/tdmap.tdmap3

README.md

@@ -0,0 +1,3 @@
+# (CubeCraft) Tower Defense
+
+## Currently in contruction 🏗️👷⚙️

assets/stats.json

@@ -0,0 +1,5 @@
+{
+	"Zombie" : {
+		
+	}
+}

include/client/Client.h

@@ -0,0 +1,24 @@
+#pragma once
+
+#include <client/IClientSocket.h>
+#include <td/common/StateMachine.h>
+
+namespace td {
+namespace client {
+
+class ClientState;
+
+class Client : public StateMachine<Client, void, float> {
+  private:
+	std::shared_ptr<IClientSocket> m_Socket;
+
+  public:
+	Client(const std::shared_ptr<IClientSocket>& a_Socket) : m_Socket(a_Socket) {}
+
+	void SendPacket(const protocol::PacketBase& a_Packet);
+
+	friend class ClientState;
+};
+
+}  // namespace client
+}  // namespace td

include/client/ClientState.h

@@ -0,0 +1,20 @@
+#pragma once
+
+#include <client/Client.h>
+#include <td/misc/SlotGuard.h>
+
+namespace td {
+namespace client {
+
+class ClientState : public Client::State, private utils::SlotGuard {
+  public:
+	ClientState(Client& a_Client);
+	virtual ~ClientState() {}
+
+  protected:
+	void SendPacket(const protocol::PacketBase& a_Packet);
+	virtual void HandlePacket(const protocol::PacketBase& a_Packet) {}
+};
+
+}  // namespace server
+}  // namespace td

include/client/IClientSocket.h

@@ -0,0 +1,23 @@
+#pragma once
+
+#include <td/Types.h>
+#include <td/misc/Signal.h>
+#include <td/protocol/packet/Packets.h>
+
+namespace td {
+namespace client {
+
+class IClientSocket {
+  public:
+	utils::Signal<> OnConnect;
+	utils::Signal<> OnDisconnect;
+	utils::Signal<const protocol::PacketBase&> OnReceive;
+
+	virtual void Send(const protocol::PacketBase& a_Packet) = 0;
+
+	IClientSocket() {}
+	virtual ~IClientSocket() {}
+};
+
+}  // namespace client
+}  // namespace td

include/client/socket/FakeSocket.h

@@ -0,0 +1,33 @@
+#pragma once
+
+#include <client/IClientSocket.h>
+
+namespace td {
+
+namespace server {
+class FakeSocket;
+}  // namespace server
+
+
+namespace client {
+
+class FakeSocket : public IClientSocket {
+  private:
+	std::shared_ptr<server::FakeSocket> m_Server;
+	PeerID m_PeerId;
+
+	struct Private{ explicit Private() = default; };
+
+  public:
+	FakeSocket(Private) {}
+	~FakeSocket() {}
+
+	static std::shared_ptr<FakeSocket> Connect(const std::shared_ptr<server::FakeSocket>& a_Server);
+
+	void ReceiveFromFakePeer(PeerID a_Peer, const protocol::PacketBase& a_Packet);
+
+	virtual void Send(const protocol::PacketBase& a_Packet) override;
+};
+
+}  // namespace client
+}  // namespace td

include/client/state/GameState.h

@@ -0,0 +1,31 @@
+#pragma once
+
+#include <client/ClientState.h>
+#include <td/game/World.h>
+#include <td/simulation/ClientSimulation.h>
+
+namespace td {
+namespace client {
+
+class GameState : public ClientState {
+  private:
+	std::shared_ptr<game::World> m_World;
+	sim::ClientSimulation m_Simulation;
+	float m_CurrentLerp;
+
+  public:
+	GameState(Client& a_Client, const std::shared_ptr<game::World>& a_World, std::uint64_t a_StepTime);
+	~GameState() {}
+
+	virtual void Update(float a_Delta) override;
+
+	float GetCurrentLerp() const {
+		return m_CurrentLerp;
+	}
+
+  protected:
+	virtual void HandlePacket(const protocol::PacketBase& a_Packet) override;
+};
+
+}  // namespace client
+}  // namespace td

include/server/IServerSocket.h

@@ -0,0 +1,33 @@
+#pragma once
+
+#include <server/PlayerIds.h>
+#include <td/misc/Signal.h>
+#include <td/protocol/packet/Packets.h>
+
+namespace td {
+namespace server {
+
+class IServerSocket {
+  public:
+	utils::Signal<PlayerID> OnConnect;
+	utils::Signal<PlayerID> OnDisconnect;
+	utils::Signal<PlayerID, const protocol::PacketBase&> OnReceive;
+
+	void Send(PlayerID a_PlayerId, const protocol::PacketBase& a_Packet);
+	void Broadcast(const protocol::PacketBase& a_Packet);
+
+	IServerSocket() {}
+	virtual ~IServerSocket() {}
+
+  private:
+	PlayerIds m_Ids;
+
+  protected:
+	void OnConnectPeer(PeerID a_PeerId);
+	void OnDisconnectPeer(PeerID a_PeerId);
+	void OnReceivePeer(PeerID a_PeerId, const protocol::PacketBase& a_Packet);
+	virtual void SendPeer(PeerID a_PeerId, const protocol::PacketBase& a_Packet) = 0;
+};
+
+}  // namespace server
+}  // namespace td

include/server/PlayerIds.h

@@ -0,0 +1,49 @@
+#pragma once
+
+#include <map>
+#include <td/Types.h>
+
+namespace td {
+namespace server {
+
+class PlayerIds {
+  private:
+	std::map<PeerID, PlayerID> m_PeerToPlayer;
+	std::map<PlayerID, PeerID> m_PlayerToPeer;
+	PlayerID m_NextId;
+
+  public:
+	PlayerIds() : m_NextId(0) {}
+	~PlayerIds() {}
+
+	void AddConnection(PeerID a_PeerId) {
+		m_PeerToPlayer.emplace(a_PeerId, m_NextId);
+		m_PlayerToPeer.emplace(m_NextId, a_PeerId);
+		m_NextId++;
+	}
+
+	PlayerID GetPlayerId(PeerID a_PeerId) const {
+		return m_PeerToPlayer.at(a_PeerId);
+	}
+
+	PeerID GetPeerId(PlayerID a_PlayerId) const {
+		return m_PlayerToPeer.at(a_PlayerId);
+	}
+
+	void RemovePeer(PeerID a_PeerId) {
+		PlayerID playerId = GetPlayerId(a_PeerId);
+		m_PeerToPlayer.erase(a_PeerId);
+		m_PlayerToPeer.erase(playerId);
+	}
+
+	auto begin() {
+		return m_PeerToPlayer.begin();
+	}
+
+	auto end() {
+		return m_PeerToPlayer.end();
+	}
+};
+
+}  // namespace server
+}  // namespace td

include/server/Server.h

@@ -0,0 +1,22 @@
+#pragma once
+
+#include <server/IServerSocket.h>
+#include <td/common/StateMachine.h>
+
+namespace td {
+namespace server {
+
+class ServerState;
+
+class Server : public StateMachine<Server, void, float> {
+  private:
+	std::shared_ptr<IServerSocket> m_Socket;
+
+  public:
+	Server(const std::shared_ptr<IServerSocket>& a_Socket) : m_Socket(a_Socket) {}
+
+	friend class ServerState;
+};
+
+}  // namespace server
+}  // namespace td

include/server/ServerState.h

@@ -0,0 +1,23 @@
+#pragma once
+
+#include <server/Server.h>
+#include <td/misc/SlotGuard.h>
+
+namespace td {
+namespace server {
+
+class ServerState : public Server::State, private utils::SlotGuard {
+  public:
+	virtual void HandlePacket(PlayerID a_Id, const protocol::PacketBase& a_Packet) = 0;
+	virtual void Update(float a_Delta) = 0;
+
+	ServerState(Server& a_Server);
+	virtual ~ServerState();
+
+  protected:
+	void SendPacket(PlayerID a_Id, const protocol::PacketBase& a_Packet);
+	void BroadcastPacket(const protocol::PacketBase& a_Packet);
+};
+
+}  // namespace server
+}  // namespace td

include/server/socket/FakeSocket.h

@@ -0,0 +1,35 @@
+#pragma once
+
+#include <client/socket/FakeSocket.h>
+#include <optional>
+#include <server/IServerSocket.h>
+
+namespace td {
+namespace server {
+
+class FakeSocket : public IServerSocket {
+  private:
+	std::vector<std::optional<std::weak_ptr<client::FakeSocket>>> m_Clients;
+
+  public:
+	FakeSocket() {}
+	~FakeSocket() {}
+
+	PeerID ConnectFakePeer(const std::shared_ptr<client::FakeSocket>& a_Socket);
+	void DisconnectFakePeer(PeerID a_Peer);
+	void ReceiveFromFakePeer(PeerID a_Peer, const protocol::PacketBase& a_Packet);
+
+  protected:
+	virtual void SendPeer(PeerID a_Peer, const protocol::PacketBase& a_Packet) override;
+
+  private:
+	/**
+	 * \return -1 if all previous ids are not free
+	 */
+	int GetNextFreeId();
+
+	friend class client::FakeSocket;
+};
+
+}  // namespace server
+}  // namespace td

include/server/state/EndGameState.h

@@ -0,0 +1,17 @@
+#pragma once
+
+#include <server/ServerState.h>
+
+namespace td {
+namespace server {
+
+class EndGameState : public ServerState {
+  private:
+	/* data */
+  public:
+	EndGameState(/* args */) {}
+	~EndGameState() {}
+};
+
+}  // namespace server
+}  // namespace td

include/server/state/GameState.h

@@ -0,0 +1,29 @@
+#pragma once
+
+#include <server/ServerState.h>
+#include <td/game/World.h>
+#include <td/simulation/ServerSimulation.h>
+
+namespace td {
+namespace server {
+
+class GameStateHandler;
+
+class GameState : public ServerState {
+  private:
+	std::shared_ptr<game::World> m_World;
+	sim::ServerSimulation m_Simulation;
+	float m_Time;
+
+  public:
+	GameState(Server& a_Server, const std::shared_ptr<game::World>& a_World);
+	~GameState() {}
+
+	virtual void HandlePacket(PlayerID a_Id, const protocol::PacketBase& a_Packet) override;
+	virtual void Update(float a_Delta) override;
+
+	friend class GameStateHandler;
+};
+
+}  // namespace server
+}  // namespace td

include/server/state/GameStateHandler.h

@@ -0,0 +1,26 @@
+#pragma once
+
+#include <td/protocol/packet/Packets.h>
+
+namespace td {
+namespace server {
+
+class GameState;
+
+class GameStateHandler : public protocol::PacketHandler {
+  private:
+	GameState& m_GameState;
+	PlayerID m_PlayerId;
+
+	using protocol::PacketHandler::Handle;
+
+  public:
+	GameStateHandler(GameState& a_GameState, PlayerID a_PlayerId);
+
+	virtual void Handle(const protocol::packets::SpawnTroopPacket& a_Packet) override;
+	virtual void Handle(const protocol::packets::PlaceTowerPacket& a_Packet) override;
+	virtual void Handle(const protocol::packets::LockStepRequestPacket& a_Packet) override;
+};
+
+}  // namespace server
+}  // namespace td

include/server/state/LobbyState.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include <server/ServerState.h>
+
+namespace td {
+namespace server {
+
+// this class is temporary useless
+class LobbyState : public ServerState {
+  private:
+	std::shared_ptr<game::World> m_World;
+  public:
+	LobbyState(Server& a_Server, const std::shared_ptr<game::World>& a_World);
+	~LobbyState() {}
+
+	virtual void HandlePacket(PlayerID a_Id, const protocol::PacketBase& a_Packet) override;
+	virtual void Update(float a_Delta) override;
+};
+
+}  // namespace server
+}  // namespace td

include/td/Constants.h

@@ -0,0 +1,10 @@
+#pragma once
+
+#include <cstdint>
+
+namespace td {
+
+constexpr int TPS = 20;
+constexpr float STEP_PERIOD = 1.0f / static_cast<float>(TPS);
+
+}  // namespace td

include/td/Maths.h

@@ -1,6 +1,6 @@
 #pragma once
 
-#include <cstdint>
+#include <sp/common/DataBufferOperators.h>
 
 namespace td {
 
@@ -183,6 +183,35 @@ T Lerp(T v0, T v1, T t) {
 
 }  // namespace maths
 
+template <typename T>
+sp::DataBuffer& operator<<(sp::DataBuffer& a_Buffer, const Vec2<T>& a_Vec) {
+	return a_Buffer << a_Vec.x << a_Vec.y;
+}
 
+template <typename T>
+sp::DataBuffer& operator>>(sp::DataBuffer& a_Buffer, Vec2<T>& a_Vec) {
+	return a_Buffer >> a_Vec.x >> a_Vec.y;
+}
+
+template <typename T>
+sp::DataBuffer& operator<<(sp::DataBuffer& a_Buffer, const Vec3<T>& a_Vec) {
+	return a_Buffer << a_Vec.x << a_Vec.y << a_Vec.z;
+}
+
+template <typename T>
+sp::DataBuffer& operator>>(sp::DataBuffer& a_Buffer, Vec3<T>& a_Vec) {
+	return a_Buffer >> a_Vec.x >> a_Vec.y >> a_Vec.z;
+}
+
+
+template <typename T>
+sp::DataBuffer& operator<<(sp::DataBuffer& a_Buffer, const Vec4<T>& a_Vec) {
+	return a_Buffer << a_Vec.x << a_Vec.y << a_Vec.z << a_Vec.w;
+}
+
+template <typename T>
+sp::DataBuffer& operator>>(sp::DataBuffer& a_Buffer, Vec4<T>& a_Vec) {
+	return a_Buffer >> a_Vec.x >> a_Vec.y >> a_Vec.z >> a_Vec.w;
+}
 
 }  // namespace td

include/td/Types.h

@@ -12,6 +12,10 @@ namespace td {
 
 using FpFloat = fpm::fixed_16_16;
 
+using StepTime = std::uint16_t;
+
+constexpr int STEP_TIME = 50;
+
 enum class TeamColor : std::int8_t {
 	None = -1,
 	Blue,
@@ -61,10 +65,7 @@ using TowerID = std::uint16_t;
 using PlayerID = std::uint8_t;
 using EntityID = std::uint16_t;
 
-struct TowerCoords {
-	std::int16_t x;
-	std::int16_t y;
-};
+using TowerCoords = Vec2<std::int16_t>;
 
 using EntityCoords = Vec2<FpFloat>;
 

include/td/common/StateMachine.h

@@ -0,0 +1,47 @@
+#pragma once
+
+#include <cassert>
+#include <memory>
+
+namespace td {
+
+template <typename TDerived, typename TReturn, typename... TArgs>
+class StateMachine {
+  public:
+	class State {
+	  public:
+		State(TDerived& a_StateMachine) : m_StateMachine(a_StateMachine) {}
+		virtual ~State() {}
+
+		virtual TReturn Update(TArgs... args) = 0;
+
+		template <typename T, typename... Args>
+		T* ChangeState(Args&&... args) {
+			return m_StateMachine.template ChangeState<T>(std::forward<Args>(args)...);
+		}
+
+	  protected:
+		TDerived& m_StateMachine;
+	};
+
+	StateMachine() {}
+	StateMachine(StateMachine&&) = default;
+	virtual ~StateMachine() {}
+
+	virtual TReturn Update(TArgs... args) {
+		assert(m_State && "You must change state at least once before updating !");
+		return m_State->Update(args...);
+	}
+
+	template <typename T, typename... Args>
+	T* ChangeState(Args&&... args) {
+		m_State = std::make_unique<T>(static_cast<TDerived&>(*this), std::forward<Args>(args)...);
+		return static_cast<T*>(m_State.get());
+	}
+
+  private:
+	std::unique_ptr<State> m_State;
+};
+
+
+}  // namespace td

include/td/common/StateStack.h

@@ -0,0 +1,69 @@
+#pragma once
+
+#include <cassert>
+#include <vector>
+#include <memory>
+
+namespace td {
+
+template <typename TDerived, typename TReturn, typename... TArgs>
+class StateStack {
+  public:
+	class State {
+	  public:
+		State(TDerived& a_StateStack) : m_StateStack(a_StateStack) {}
+		virtual ~State() {}
+
+		virtual TReturn Update(TArgs... args) = 0;
+
+	  protected:
+		/**
+		 * \brief Called when enabled (can be used to connect signals)
+		 */
+		virtual void OnEnable() {}
+
+		/**
+		 * \brief Called when disabled (can be used to disconnect signals)
+		 */
+		virtual void OnDisable() {}
+
+	  protected:
+		TDerived& m_StateStack;
+
+		friend class StateStack;
+	};
+
+	StateStack() {}
+	StateStack(StateStack&&) = default;
+	virtual ~StateStack() {}
+
+	virtual TReturn Update(TArgs... args) {
+		assert(!m_States.empty() && "You must push at least one state before updating !");
+		return m_States.back()->Update(args...);
+	}
+
+	void PopState() {
+		assert(!m_States.empty() && "You must push at least one state before poping !");
+		m_States.back()->OnDisable();
+		m_States.pop_back();
+		if (m_States.empty())
+			return;
+		m_States.back()->OnEnable();
+	}
+
+	template <typename T, typename... Args>
+	T* PushState(Args&&... args) {
+		if (!m_States.empty())
+			m_States.back()->OnDisable();
+		auto newState = std::make_unique<T>(static_cast<TDerived&>(*this), std::forward<Args>(args)...);
+		newState->OnEnable();
+		m_States.push_back(std::move(newState));
+		return static_cast<T*>(newState.get());
+	}
+
+  private:
+	std::vector<std::unique_ptr<State>> m_States;
+};
+
+
+}  // namespace td

include/td/display/Display.h

@@ -2,39 +2,14 @@
 
 #include <string>
 
-#include <SDL3/SDL_video.h>
 #include <SDL3/SDL_keycode.h>
+#include <SDL3/SDL_video.h>
+#include <td/common/StateMachine.h>
 #include <td/misc/Signal.h>
 
 namespace td {
 
-class Display {
-  public:
-	utils::Signal<float> OnAspectRatioChange;
-	utils::Signal<SDL_Keycode> OnKeyDown;
-
-	Display(int a_Width, int a_Height, const std::string& a_Title);
-	~Display();
-
-	void PollEvents();
-	void Update();
-
-	bool IsCloseRequested() {
-		return m_ShouldClose;
-	}
-
-	float GetAspectRatio() {
-		return m_AspectRatio;
-	}
-	
-	int GetWindowWidth() {
-		return m_LastWidth;
-	}
-
-	int GetWindowHeight() {
-		return m_LastHeight;
-	}
-
+class Display : public StateMachine<Display, void, float> {
   private:
 	SDL_Window* m_Window;
 	SDL_GLContext m_GLContext;
@@ -43,6 +18,33 @@ class Display {
 	float m_AspectRatio;
 
 	bool m_ShouldClose;
+
+  public:
+	utils::Signal<float> OnAspectRatioChange;
+	utils::Signal<SDL_Keycode> OnKeyDown;
+
+	Display(int a_Width, int a_Height, const std::string& a_Title);
+	~Display();
+
+	void PollEvents();
+	void Update(float a_Delta) override;
+	void Close();
+
+	bool IsCloseRequested() {
+		return m_ShouldClose;
+	}
+
+	float GetAspectRatio() {
+		return m_AspectRatio;
+	}
+
+	int GetWindowWidth() {
+		return m_LastWidth;
+	}
+
+	int GetWindowHeight() {
+		return m_LastHeight;
+	}
 };
 
 }  // namespace td

include/td/display/DisplayState.h

@@ -0,0 +1,16 @@
+#pragma once
+
+#include <td/display/Display.h>
+#include <td/misc/SlotGuard.h>
+
+namespace td {
+class DisplayState : public Display::State, private utils::SlotGuard {
+  public:
+	DisplayState(Display& a_Display);
+	virtual ~DisplayState() {}
+
+  protected:
+	virtual void OnAspectRatioChange(float a_Ratio) {}
+	virtual void OnKeyDown(SDL_Keycode a_Key) {}
+};
+}  // namespace td

include/td/display/menu/CreatePartyMenu.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#include <td/display/state/MainMenuState.h>
+
+namespace td {
+
+class CreatePartyMenu : public MainMenuState::Menu {
+  public:
+	CreatePartyMenu(MainMenuState& a_MainMenu);
+	~CreatePartyMenu();
+
+	virtual void Update() override;
+};
+
+}  // namespace td

include/td/display/menu/JoinPartyMenu.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#include <td/display/state/MainMenuState.h>
+
+namespace td {
+
+class JoinPartyMenu : public MainMenuState::Menu {
+  public:
+	JoinPartyMenu(MainMenuState& a_MainMenu);
+	~JoinPartyMenu();
+
+	virtual void Update() override;
+};
+
+}  // namespace td

include/td/display/menu/MainMenu.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#include <td/display/state/MainMenuState.h>
+
+namespace td {
+
+class MainMenu : public MainMenuState::Menu {
+  public:
+	MainMenu(MainMenuState& a_MainMenu);
+	~MainMenu();
+
+	virtual void Update() override;
+};
+
+}  // namespace td

include/td/display/menu/SettingsMenu.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#include <td/display/state/MainMenuState.h>
+
+namespace td {
+
+class SettingsMenu : public MainMenuState::Menu {
+  public:
+	SettingsMenu(MainMenuState& a_MainMenu);
+	~SettingsMenu();
+
+	virtual void Update() override;
+};
+
+}  // namespace td

include/td/display/state/DebugWorldState.h

@@ -0,0 +1,31 @@
+#pragma once
+
+#include <client/Client.h>
+#include <server/Server.h>
+#include <td/display/DisplayState.h>
+#include <td/render/Renderer.h>
+#include <td/simulation/ClientSimulation.h>
+#include <client/state/GameState.h>
+
+namespace td {
+
+class DebugWorldState : public DisplayState {
+  private:
+	render::RenderPipeline m_Renderer;
+	render::Camera m_Camera;
+	std::unique_ptr<client::Client> m_Client;
+	std::unique_ptr<server::Server> m_Server;
+	client::GameState* m_ClientState;
+
+  public:
+	DebugWorldState(Display& a_Display);
+	~DebugWorldState();
+
+	virtual void Update(float a_Delta) override;
+
+  protected:
+	virtual void OnAspectRatioChange(float a_Ratio) override;
+	virtual void OnKeyDown(SDL_Keycode a_Key) override;
+};
+
+}  // namespace td

include/td/display/state/MainMenuState.h

@@ -0,0 +1,27 @@
+#pragma once
+
+#include <td/common/StateStack.h>
+#include <td/display/DisplayState.h>
+
+namespace td {
+
+class MainMenuState;
+
+using MainMenuStateStack = StateStack<MainMenuState, void>;
+
+class MainMenuState : public DisplayState, public MainMenuStateStack {
+  public:
+	using Menu = MainMenuStateStack::State;
+
+	MainMenuState(Display& a_Display);
+	~MainMenuState();
+
+	virtual void Update(float a_Delta) override;
+
+	void RenderBackButton();
+
+  protected:
+	virtual void OnKeyDown(SDL_Keycode a_Key) override;
+};
+
+}  // namespace td

include/td/game/World.h

@@ -1,25 +1,25 @@
 #pragma once
 
-#include <td/simulation/WorldTicker.h>
 #include <td/game/WorldTypes.h>
 #include <td/protocol/packet/Packets.h>
+#include <td/simulation/WorldTicker.h>
 
 namespace td {
 namespace game {
 
 class World {
   protected:
+	// header
 	TowerTileColorPalette m_TowerPlacePalette;
 	Color m_WalkablePalette;
 	std::vector<Color> m_DecorationPalette;
 	Color m_Background;
-
-	ChunkList m_Chunks;
-
 	SpawnColorPalette m_SpawnColorPalette;
-
 	TilePalette m_TilePalette;
 
+	//data
+	ChunkList m_Chunks;
+
 	std::shared_ptr<sim::WorldSnapshot> m_CurrentState;
 	std::shared_ptr<sim::WorldSnapshot> m_NextState;
 
@@ -28,6 +28,7 @@ class World {
 
   public:
 	World();
+	World(World&&) = default;
 
 	bool LoadMap(const protocol::pdata::WorldHeader& worldHeader);
 	bool LoadMap(const protocol::pdata::WorldData& worldData);
@@ -61,7 +62,7 @@ class World {
 
 	TilePtr GetTilePtr(TileIndex index) const {
 		if (index == 0)
-			return nullptr;
+			return TilePtr(nullptr);
 		return m_TilePalette.at(index - 1);
 	}
 
@@ -130,12 +131,9 @@ class World {
   private:
 	void TickMobs(std::uint64_t delta);
 	void CleanDeadMobs();
-
 };
 
-
-
-
+using WorldPtr = std::shared_ptr<World>;
 
 }  // namespace game
-}  // namespace td
+}  // namespace td

include/td/game/WorldTypes.h

@@ -67,7 +67,7 @@ using TileFactory = sp::MessageFactory<Tile, AllTiles>;
 
 class TileHandler : public sp::GenericHandler<AllTiles> {};
 
-using TilePtr = std::shared_ptr<sp::SerializableMessage<TileFactory>>;
+using TilePtr = sp::SerializableMessage<TileFactory>;
 
 // typedef std::shared_ptr<Tile> TilePtr;
 typedef std::vector<std::uint16_t> ChunkPalette;

include/td/misc/Signal.h

@@ -8,16 +8,27 @@
 namespace td {
 namespace utils {
 
+/**
+ * \brief Signal class
+ */
 template <typename... Args>
-class Signal : private NonCopyable {
-  private:
-	using CallBack = std::function<void(Args...)>;
+class SignalRaw : private NonCopyable {
+  public:
+	using FnType = void(Args...);
+	using CallBack = std::function<FnType>;
 
+  private:
 	std::vector<CallBack> m_Callbacks;
 
   public:
-	void Connect(CallBack&& a_Callback) {
-		m_Callbacks.push_back(std::move(a_Callback));
+	void Connect(const CallBack& a_Callback) {
+		m_Callbacks.push_back(a_Callback);
+	}
+
+	void Disconnect(const CallBack& a_Callback) {
+		auto it = std::find_if(m_Callbacks.begin(), m_Callbacks.end(),
+			[&a_Callback](CallBack& callback) { return a_Callback.template target<FnType>() == callback.template target<FnType>(); });
+		m_Callbacks.erase(it);
 	}
 
 	void operator()(Args... args) const {
@@ -27,5 +38,63 @@ class Signal : private NonCopyable {
 	}
 };
 
+/**
+ * \brief Memory managed Signal class
+ */
+template <typename... Args>
+class Signal {
+  public:
+	using SignalBase = SignalRaw<Args...>;
+	using CallBack = typename SignalBase::CallBack;
+	using SignalPtr = std::shared_ptr<SignalBase>;
+	class ConnectionGuard;
+
+  private:
+	SignalPtr m_Signal;
+
+  public:
+	Signal() : m_Signal(std::make_shared<SignalBase>()) {}
+	Signal(const Signal&) = default;
+
+	void Connect(const CallBack& a_Callback) {
+		m_Signal->Connect(a_Callback);
+	}
+
+	[[nodiscard]] std::unique_ptr<ConnectionGuard> ConnectSafe(const CallBack& a_Callback) {
+		Connect(a_Callback);
+		return std::make_unique<ConnectionGuard>(*this, a_Callback);
+	}
+
+	void Disconnect(const CallBack& a_Callback) {
+		m_Signal->Disconnect(a_Callback);
+	}
+
+	void operator()(Args... args) const {
+		m_Signal->operator()(args...);
+	}
+};
+
+class Connection {
+  public:
+	virtual ~Connection() {}
+};
+
+template <typename... Args>
+class Signal<Args...>::ConnectionGuard : public Connection {
+  private:
+	using CallBack = typename Signal<Args...>::CallBack;
+
+	std::weak_ptr<SignalRaw<Args...>> m_Signal;
+	CallBack m_Callback;
+
+  public:
+	ConnectionGuard(const Signal<Args...>& a_Signal, const CallBack& a_Callback) : m_Signal(a_Signal.m_Signal), m_Callback(a_Callback) {}
+
+	~ConnectionGuard() {
+		if (!m_Signal.expired())
+			m_Signal.lock()->Disconnect(m_Callback);
+	}
+};
+
 }  // namespace utils
 }  // namespace td

include/td/misc/SlotGuard.h

@@ -0,0 +1,32 @@
+#pragma once
+
+#include <td/misc/Signal.h>
+
+namespace td {
+namespace utils {
+
+/**
+ * \brief Wrapper class to automatically disconnect from a Signal on object destruction
+ * \note You should inherit this class privately
+ * \sa Signal
+ */
+class SlotGuard {
+  private:
+	std::vector<std::unique_ptr<Connection>> m_Connections;
+
+  public:
+	/**
+	 * \brief Connect a signal to a function (with the same signature)
+	 */
+	template <typename... Args>
+	void Connect(Signal<Args...> a_Signal, const typename Signal<Args...>::CallBack& a_Callback) {
+		m_Connections.push_back(a_Signal.ConnectSafe(a_Callback));
+	}
+
+	void Disconnect() {
+		m_Connections.clear();
+	}
+};
+
+}  // namespace utils
+}  // namespace td

include/td/network/EnetClient.h

@@ -0,0 +1 @@
+#pragma once

include/td/network/EnetConnection.h

@@ -0,0 +1 @@
+#pragma once

include/td/network/EnetServer.h

@@ -0,0 +1 @@
+#pragma once

include/td/protocol/command/CommandData.h

@@ -21,10 +21,8 @@ struct UpgradeTower {
 	sp::BitField<std::uint8_t, 4> m_Upgrade;
 };
 
-using EntityTypeInt = std::uint8_t;
-
 struct SpawnTroop {
-	sp::BitField<EntityTypeInt, 5> m_Type;
+	sp::BitField<EntityType, 5> m_Type;
 	sp::BitField<std::uint8_t, 3> m_Level;
 	EntityCoords m_Position;
 	PlayerID m_Sender;

include/td/protocol/command/Commands.h

@@ -7,7 +7,6 @@
 
 #include <memory>
 #include <sp/common/GenericHandler.h>
-#include <sp/io/SerializableMessage.h>
 #include <sp/protocol/ConcreteMessage.h>
 #include <sp/protocol/MessageDispatcher.h>
 #include <sp/protocol/MessageFactory.h>
@@ -15,6 +14,8 @@
 #include <td/common/NonCopyable.h>
 #include <td/protocol/command/CommandData.h>
 
+#include <sp/io/SerializableMessage.h>
+
 namespace td {
 namespace protocol {
 
@@ -58,9 +59,9 @@ using CommandDispatcher = sp::MessageDispatcher<CommandBase>;
 
 using CommandFactory = sp::MessageFactory<CommandBase, AllCommands>;
 
-using LockStep = std::vector<std::shared_ptr<CommandBase>>;
+using CommandPtr = sp::SerializableMessage<CommandFactory>;
 
-using CommandPtr = std::unique_ptr<sp::SerializableMessage<CommandFactory>>;
+using LockStep = std::vector<CommandPtr>;
 
 }  // namespace protocol
 }  // namespace td

include/td/protocol/packet/PacketData.h

@@ -7,7 +7,11 @@
 #include <td/game/WorldTypes.h>
 
 // Make it dynamic ?
+#ifdef NDEBUG
 #define LOCKSTEP_BUFFER_SIZE 10
+#else
+#define LOCKSTEP_BUFFER_SIZE 1
+#endif
 
 namespace td {
 namespace protocol {
@@ -45,7 +49,7 @@ struct PlayerLeave {
 
 struct PredictCommand {
 	CommandPtr m_Command;
-	std::uint16_t m_FrameNumber;
+	StepTime m_FrameNumber;
 };
 
 /** Keep alive */
@@ -73,8 +77,8 @@ struct BeginGame {
 };
 
 struct LockSteps {
-	std::uint16_t m_FirstFrameNumber;
-	Array<LockStep, LOCKSTEP_BUFFER_SIZE> m_LockSteps;
+	StepTime m_FirstFrameNumber;
+	std::array<LockStep, LOCKSTEP_BUFFER_SIZE> m_LockSteps;
 };
 
 struct WorldHeader {
@@ -95,6 +99,25 @@ struct WorldData {
 	game::ChunkList m_Chunks;
 };
 
+// TODO: spawn multiple troops at the same time
+struct SpawnTroop {
+	sp::BitField<EntityType, 5> m_Type;
+	sp::BitField<std::uint8_t, 3> m_Level;
+};
+
+struct PlaceTower {
+	TowerType m_Type;
+	TowerCoords m_Position;
+};
+
+struct LockStepRequest {
+	std::vector<StepTime> m_Missing;
+};
+
+struct LockStepResponse {
+	std::map<StepTime, LockStep> m_Steps;
+};
+
 }  // namespace pdata
 }  // namespace protocol
 }  // namespace td

include/td/protocol/packet/PacketSerialize.h

@@ -4,44 +4,15 @@
 
 namespace td {
 
-template <typename T>
-sp::DataBuffer& operator<<(sp::DataBuffer& a_Buffer, const Vec2<T>& a_Vec) {
-	return a_Buffer << a_Vec.x << a_Vec.y;
-}
 
-template <typename T>
-sp::DataBuffer& operator>>(sp::DataBuffer& a_Buffer, Vec2<T>& a_Vec) {
-	return a_Buffer >> a_Vec.x >> a_Vec.y;
-}
-
-template <typename T>
-sp::DataBuffer& operator<<(sp::DataBuffer& a_Buffer, const Vec3<T>& a_Vec) {
-	return a_Buffer << a_Vec.x << a_Vec.y << a_Vec.z;
-}
-
-template <typename T>
-sp::DataBuffer& operator>>(sp::DataBuffer& a_Buffer, Vec3<T>& a_Vec) {
-	return a_Buffer >> a_Vec.x >> a_Vec.y >> a_Vec.z;
-}
-
-
-template <typename T>
-sp::DataBuffer& operator<<(sp::DataBuffer& a_Buffer, const Vec4<T>& a_Vec) {
-	return a_Buffer << a_Vec.x << a_Vec.y << a_Vec.z << a_Vec.w;
-}
-
-template <typename T>
-sp::DataBuffer& operator>>(sp::DataBuffer& a_Buffer, Vec4<T>& a_Vec) {
-	return a_Buffer >> a_Vec.x >> a_Vec.y >> a_Vec.z >> a_Vec.w;
-}
 
 namespace game {
 
 sp::DataBuffer& operator<<(sp::DataBuffer& a_Buffer, const TeamCastle& a_Castle);
 sp::DataBuffer& operator>>(sp::DataBuffer& a_Buffer, TeamCastle& a_Castle);
 
-sp::DataBuffer& operator<<(sp::DataBuffer& a_Buffer, const ChunkPtr& a_Chunk);
-sp::DataBuffer& operator>>(sp::DataBuffer& a_Buffer, ChunkPtr& a_Chunk);
+sp::DataBuffer& operator<<(sp::DataBuffer& a_Buffer, const Spawn& a_Spawn);
+sp::DataBuffer& operator>>(sp::DataBuffer& a_Buffer, Spawn& a_Spawn);
 
 }  // namespace game
 }  // namespace td

include/td/protocol/packet/Packets.h

@@ -8,11 +8,11 @@
 #include <td/common/NonCopyable.h>
 #include <td/protocol/packet/PacketData.h>
 
+#include <sp/common/GenericHandler.h>
 #include <sp/protocol/ConcreteMessage.h>
 #include <sp/protocol/MessageBase.h>
 #include <sp/protocol/MessageDispatcher.h>
 #include <sp/protocol/MessageFactory.h>
-#include <sp/common/GenericHandler.h>
 
 namespace td {
 namespace protocol {
@@ -22,12 +22,16 @@ enum class PacketID : std::uint8_t {
 	BeginGame,
 	Disconnect,
 	KeepAlive,
+	LockStepRequest,
+	LockStepResponse,
 	LockSteps,
 	LoggingSuccess,
+	PlaceTower,
 	PlayerJoin,
 	PlayerLeave,
 	PlayerLogin,
 	PredictCommand,
+	SpawnTroop,
 	WorldHeader,
 	WorldData,
 };
@@ -47,20 +51,25 @@ using BeginGamePacket = PacketMessage<pdata::BeginGame, PacketID::BeginGame>;
 using ChatMessagePacket = PacketMessage<pdata::ChatMessage, PacketID::ChatMessage>;
 using DisconnectPacket = PacketMessage<pdata::Disconnect, PacketID::Disconnect>;
 using KeepAlivePacket = PacketMessage<pdata::KeepAlive, PacketID::KeepAlive>;
+using LockStepRequestPacket = PacketMessage<pdata::LockStepRequest, PacketID::LockStepRequest>;
+using LockStepResponsePacket = PacketMessage<pdata::LockStepResponse, PacketID::LockStepResponse>;
 using LockStepsPacket = PacketMessage<pdata::LockSteps, PacketID::LockSteps>;
 using LoggingSuccessPacket = PacketMessage<pdata::LoggingSuccess, PacketID::LoggingSuccess>;
+using PlaceTowerPacket = PacketMessage<pdata::PlaceTower, PacketID::PlaceTower>;
 using PlayerJoinPacket = PacketMessage<pdata::PlayerJoin, PacketID::PlayerJoin>;
 using PlayerLeavePacket = PacketMessage<pdata::PlayerLeave, PacketID::PlayerLeave>;
 using PlayerLoginPacket = PacketMessage<pdata::PlayerLogin, PacketID::PlayerLogin>;
 using PredictCommandPacket = PacketMessage<pdata::PredictCommand, PacketID::PredictCommand>;
+using SpawnTroopPacket = PacketMessage<pdata::SpawnTroop, PacketID::SpawnTroop>;
 using WorldHeaderPacket = PacketMessage<pdata::WorldHeader, PacketID::WorldHeader>;
 using WorldDataPacket = PacketMessage<pdata::WorldData, PacketID::WorldData>;
 
 }  // namespace packets
 
 using AllPackets = std::tuple<packets::BeginGamePacket, packets::ChatMessagePacket, packets::DisconnectPacket,
-	packets::KeepAlivePacket, packets::LockStepsPacket, packets::LoggingSuccessPacket, packets::PlayerJoinPacket,
-	packets::PlayerLeavePacket, packets::PlayerLoginPacket, packets::PredictCommandPacket, packets::WorldHeaderPacket, packets::WorldDataPacket>;
+	packets::KeepAlivePacket, packets::LockStepRequestPacket, packets::LockStepResponsePacket, packets::LockStepsPacket, packets::LoggingSuccessPacket, packets::PlaceTowerPacket,
+	packets::PlayerJoinPacket, packets::PlayerLeavePacket, packets::PlayerLoginPacket, packets::PredictCommandPacket,
+	packets::SpawnTroopPacket, packets::WorldHeaderPacket, packets::WorldDataPacket>;
 
 class PacketHandler : public sp::GenericHandler<AllPackets> {};
 

include/td/render/Renderer.h

@@ -4,6 +4,7 @@
 #include <td/render/Camera.h>
 #include <td/render/loader/GLLoader.h>
 #include <td/render/shader/CameraShaderProgram.h>
+#include <td/misc/SlotGuard.h>
 
 namespace td {
 namespace render {
@@ -17,7 +18,7 @@ class BasicRenderer {
 };
 
 template <typename TShader>
-class Renderer : public BasicRenderer {
+class Renderer : public BasicRenderer, private utils::SlotGuard {
   protected:
 	std::unique_ptr<TShader> m_Shader;
 	Camera& m_Camera;
@@ -62,12 +63,12 @@ class RenderPipeline {
 
 template <typename TShader>
 Renderer<TShader>::Renderer(Camera& a_Camera) : m_Shader(std::make_unique<TShader>()), m_Camera(a_Camera) {
-	a_Camera.OnPerspectiveChange.Connect([this]() {
+	Connect(a_Camera.OnPerspectiveChange, [this](){
 		m_Shader->Start();
 		m_Shader->SetProjectionMatrix(m_Camera.GetProjectionMatrix());
 	});
 
-	a_Camera.OnViewChange.Connect([this]() {
+	Connect(a_Camera.OnViewChange, [this]() {
 		m_Shader->Start();
 		m_Shader->SetViewMatrix(m_Camera.GetViewMatrix());
 	});

include/td/simulation/ClientSimulation.h

@@ -0,0 +1,70 @@
+#pragma once
+
+#include <td/game/World.h>
+#include <optional>
+#include <td/misc/Signal.h>
+
+namespace td {
+namespace sim {
+
+using GameHistory = std::vector<td::protocol::LockStep>;
+using GameBuffer = std::vector<std::optional<td::protocol::LockStep>>;
+
+// TODO: OnEnd signal
+class ClientSimulation : public protocol::PacketHandler {
+  private:
+	std::uint64_t m_StepTime;
+	std::shared_ptr<game::World> m_World;
+	GameBuffer m_History;
+	float m_CurrentTime;
+	StepTime m_CurrentStep;
+
+	std::shared_ptr<WorldSnapshot> m_LastSnapshot;
+	StepTime m_LastValidStep;
+
+	static const protocol::LockStep EMPTY_LOCKSTEP;
+
+	using protocol::PacketHandler::Handle;
+
+  public:
+	utils::Signal<const std::vector<StepTime>&> OnMissingLockSteps;
+
+	/**
+	 * \brief Replay constructor
+	 * \param a_StepTime in ms
+	 */
+	ClientSimulation(std::shared_ptr<game::World> a_World, GameHistory&& a_History, std::uint64_t a_StepTime);
+
+	/**
+	 * \brief Live update constructor (continuous game updates)
+	 * \param a_StepTime in ms
+	 */
+	ClientSimulation(std::shared_ptr<game::World> a_World, std::uint64_t a_StepTime);
+
+	/**
+	 * \return the progress [0-1] between two steps
+	 */
+	float Update(float a_Delta);
+
+	virtual void Handle(const protocol::packets::LockStepsPacket& a_LockSteps) override;
+	virtual void Handle(const protocol::packets::LockStepResponsePacket& a_LockSteps) override;
+
+  private:
+	/**
+	 * \returns false if the empty lockstep was used
+	 */
+	bool Step();
+
+	/**
+	 * \brief Ticks a_Count times
+	 */
+	std::size_t FastForward(std::size_t a_Count);
+
+	/**
+	 * \brief Tries to recompute simulation if needed (for example in late command receival)
+	 */
+	void FastReplay();
+};
+
+}  // namespace sim
+}  // namespace td

include/td/simulation/GameHistory.h

@@ -1,37 +0,0 @@
-#pragma once
-
-#include <optional>
-#include <td/protocol/command/Commands.h>
-#include <td/protocol/packet/Packets.h>
-
-namespace td {
-namespace game {
-
-class GameHistory {
-  private:
-	using HistorySizeType = std::uint16_t;
-
-	std::vector<std::optional<protocol::LockStep>> m_History;
-	
-	HistorySizeType m_Cursor;
-
-  public:
-	GameHistory();
-
-	void SetLockStep(HistorySizeType a_Index, protocol::LockStep&& a_LockStep);
-
-	const protocol::LockStep& GetLockStep(HistorySizeType a_Index) const;
-
-	bool HasLockStep(HistorySizeType a_Index) const;
-
-	const protocol::LockStep& GetNextStep();
-
-	bool HasNextStep() const;
-
-	void FromPacket(td::protocol::pdata::LockSteps&& a_Steps);
-
-	td::protocol::packets::LockStepsPacket ToPacket(HistorySizeType a_StartIndex);
-};
-
-}  // namespace game
-}  // namespace td

include/td/simulation/RealTimeSimulation.h

@@ -1,62 +0,0 @@
-#pragma once
-
-#include <td/game/World.h>
-#include <optional>
-
-namespace td {
-namespace sim {
-
-using GameHistory = std::vector<td::protocol::LockStep>;
-using GameBuffer = std::vector<std::optional<td::protocol::LockStep>>;
-
-class RealTimeSimulation {
-  private:
-	std::uint64_t m_StepTime;
-	game::World& m_World;
-	GameBuffer m_History;
-	std::uint64_t m_CurrentTime;
-	std::uint64_t m_LastTime;
-	std::size_t m_CurrentStep;
-
-	std::shared_ptr<WorldSnapshot> m_LastSnapshot;
-	std::uint64_t m_LastValidStep;
-
-	static const protocol::LockStep EMPTY_LOCKSTEP;
-
-  public:
-	/**
-	 * \brief Replay constructor
-	 * \param a_StepTime in ms
-	 */
-	RealTimeSimulation(game::World& a_World, const GameHistory& a_History, std::uint64_t a_StepTime);
-
-	/**
-	 * \brief Live update constructor (continuous game updates)
-	 * \param a_StepTime in ms
-	 */
-	RealTimeSimulation(game::World& a_World, std::uint64_t a_StepTime);
-
-	/**
-	 * \return the progress [0-1] between two steps
-	 */
-	float Update();
-
-	void HandlePacket(const protocol::packets::LockStepsPacket& a_LockSteps);
-	void HandlePacket(const protocol::packets::PredictCommandPacket& a_Predict);
-
-  private:
-	void Step();
-
-	/**
-	 * \brief Ticks a_Count times
-	 */
-	void FastForward(std::size_t a_Count);
-
-	/**
-	 * \brief Tries to recompute simulation if needed (for example in late command receival)
-	 */
-	void FastReplay();
-};
-
-}  // namespace sim
-}  // namespace td

include/td/simulation/ServerSimulation.h

@@ -0,0 +1,39 @@
+#pragma once
+
+#include <mutex>
+#include <td/game/World.h>
+
+namespace td {
+namespace sim {
+
+// TODO: OnEnd signal
+/**
+ * \note This class is thread safe
+ */
+class ServerSimulation : public protocol::CommandHandler {
+  private:
+	std::mutex m_Mutex;
+	game::World& m_World;
+	std::uint64_t m_StepTime;
+	std::uint64_t m_CurrentTime;
+	std::vector<td::protocol::LockStep> m_History;
+
+	using protocol::CommandHandler::Handle;
+
+  public:
+	ServerSimulation(game::World& a_World, std::uint64_t a_StepTime);
+
+	protocol::packets::LockStepsPacket Update();
+
+	protocol::packets::LockStepsPacket MakePacket();
+
+	// no checks are done !
+
+	virtual void Handle(const protocol::commands::SpawnTroopCommand& a_SpawnTroop) override;
+	virtual void Handle(const protocol::commands::PlaceTowerCommand& a_PlaceTower) override;
+
+	protocol::packets::LockStepResponsePacket GetResponse(const protocol::packets::LockStepRequestPacket& a_Missing) const;
+};
+
+}  // namespace sim
+}  // namespace td

src/client/Client.cpp

@@ -0,0 +1,11 @@
+#include <client/Client.h>
+
+namespace td {
+namespace client {
+
+void Client::SendPacket(const protocol::PacketBase& a_Packet) {
+	m_Socket->Send(a_Packet);
+}
+
+}  // namespace client
+}  // namespace td

src/client/ClientState.cpp

@@ -0,0 +1,16 @@
+#include <client/ClientState.h>
+#include <client/Client.h>
+
+namespace td {
+namespace client {
+
+ClientState::ClientState(Client& a_Client) : Client::State(a_Client) {
+	Connect(m_StateMachine.m_Socket->OnReceive, std::bind(&ClientState::HandlePacket, this, std::placeholders::_1));
+}
+
+void ClientState::SendPacket(const protocol::PacketBase& a_Packet) {
+	m_StateMachine.m_Socket->Send(a_Packet);
+}
+
+}  // namespace server
+}  // namespace td

src/client/socket/FakeSocket.cpp

@@ -0,0 +1,19 @@
+#include <client/socket/FakeSocket.h>
+#include <server/socket/FakeSocket.h>
+
+namespace td {
+namespace client {
+
+void FakeSocket::Send(const protocol::PacketBase& a_Packet) {
+	m_Server->OnReceivePeer(m_PeerId, a_Packet);
+}
+
+std::shared_ptr<FakeSocket> FakeSocket::Connect(const std::shared_ptr<server::FakeSocket>& a_Server) {
+	auto socket = std::make_shared<FakeSocket>(Private());
+	socket->m_Server = a_Server;
+	socket->m_PeerId = a_Server->ConnectFakePeer(socket);
+	return socket;
+}
+
+}  // namespace client
+}  // namespace td

src/client/state/GameState.cpp

@@ -0,0 +1,41 @@
+#include <client/state/GameState.h>
+
+namespace td {
+namespace client {
+
+class ClientHandler : public protocol::PacketHandler {
+  private:
+	sim::ClientSimulation& m_Simulation;
+
+	using protocol::PacketHandler::Handle;
+
+  public:
+	ClientHandler(sim::ClientSimulation& a_Simulation) : m_Simulation(a_Simulation) {}
+
+	void Handle(const protocol::packets::LockStepsPacket& a_LockStep) {
+		m_Simulation.Handle(a_LockStep);
+	}
+
+	void Handle(const protocol::packets::LockStepResponsePacket& a_LockStep) {
+		m_Simulation.Handle(a_LockStep);
+	}
+};
+
+GameState::GameState(Client& a_Client, const std::shared_ptr<game::World>& a_World, std::uint64_t a_StepTime) :
+	ClientState(a_Client), m_World(a_World), m_Simulation(a_World, a_StepTime) {
+	m_Simulation.OnMissingLockSteps.Connect([this](const std::vector<td::StepTime>& a_MissingSteps) {
+		SendPacket(protocol::packets::LockStepRequestPacket(a_MissingSteps));
+	});
+}
+
+void GameState::HandlePacket(const protocol::PacketBase& a_Packet) {
+	ClientHandler handler(m_Simulation);
+	a_Packet.Dispatch(handler);
+}
+
+void GameState::Update(float a_Delta) {
+	m_CurrentLerp = m_Simulation.Update(a_Delta);
+}
+
+}  // namespace client
+}  // namespace td

src/main.cpp

@@ -1,135 +1,24 @@
-#include <iostream>
+#include <chrono>
+#include <td/display/state/MainMenuState.h>
 
-#include <fstream>
-#include <td/game/World.h>
-#include <td/input/Display.h>
-#include <td/protocol/packet/PacketSerialize.h>
-#include <td/protocol/packet/Packets.h>
-#include <td/render/renderer/EntityRenderer.h>
-#include <td/render/renderer/TowerRenderer.h>
-#include <td/render/renderer/WorldRenderer.h>
-#include <td/simulation/RealTimeSimulation.h>
-
-#include <sp/common/DataBuffer.h>
-#include <sp/extensions/Compress.h>
-#include <sp/io/MessageStream.h>
-#include <sp/io/StdIo.h>
-
-class WorldApply : public td::protocol::PacketHandler {
-  private:
-	td::game::World& m_World;
-	using td::protocol::PacketHandler::Handle;
-
-  public:
-	WorldApply(td::game::World& a_World) : m_World(a_World) {}
-
-	void Handle(const td::protocol::packets::WorldHeaderPacket& a_Header) override {
-		m_World.LoadMap(*a_Header);
-	}
-
-	void Handle(const td::protocol::packets::WorldDataPacket& a_Data) override {
-		m_World.LoadMap(*a_Data);
-	}
-};
-
-void Save(const td::protocol::PacketBase& header, const td::protocol::PacketBase& data) {
-	auto comp = std::make_shared<sp::ZlibCompress>();
-
-	std::ofstream fStream("test/tdmap.tdmap3");
-	auto out = std::make_shared<sp::StdOuput>(fStream);
-
-	sp::MessageStream<td::protocol::PacketFactory> stream(std::move(out), std::move(comp));
-
-	stream.WriteMessage(header);
-	stream.WriteMessage(data);
+float GetDelta() {
+	static std::chrono::time_point<std::chrono::system_clock> m_LastTime = std::chrono::system_clock::now();
+	auto timeElapsed = std::chrono::system_clock::now() - m_LastTime;
+	float timeSeconds = std::chrono::duration<float, std::chrono::seconds::period>(timeElapsed).count();
+	m_LastTime = std::chrono::system_clock::now();
+	return timeSeconds;
 }
 
-td::game::World GetWorld() {
-	auto comp = std::make_shared<sp::ZlibCompress>();
-
-	std::ifstream fStream("test/tdmap.tdmap2");
-	auto out = std::make_shared<sp::StdInput>(fStream);
-
-	sp::MessageStream<td::protocol::PacketFactory> stream(std::move(out), std::move(comp));
-
-	auto header = stream.ReadMessage();
-	auto data = stream.ReadMessage();
-
-	td::game::World w;
-	WorldApply wa(w);
-
-	td::protocol::PacketDispatcher d;
-	d.RegisterHandler(td::protocol::PacketID::WorldData, &wa);
-	d.RegisterHandler(td::protocol::PacketID::WorldHeader, &wa);
-
-	d.Dispatch(*header);
-	d.Dispatch(*data);
-
-	Save(*header, *data);
-
-	return w;
-}
-
-void FastForward(td::game::World& a_World, const td::sim::GameHistory& a_LockSteps) {
-	const td::FpFloat delta = td::FpFloat(1) / td::FpFloat(75);
-	for (const auto& lockstep : a_LockSteps) {
-		a_World.Tick(lockstep, delta);
-	}
-}
-
-td::sim::GameHistory GetCustomHistory() {
-	constexpr std::size_t MAX_COUNT = 20 * 60 * 40;
-
-	td::sim::GameHistory gh(MAX_COUNT);
-
-	auto spawn = std::make_shared<td::protocol::commands::SpawnTroopCommand>(0, 0, td::Vec2fp{td::FpFloat(77), td::FpFloat(13)}, 0);
-	gh[0].push_back(spawn);
-
-	auto tower = std::make_shared<td::protocol::commands::PlaceTowerCommand>(td::TowerType::Archer, 0, td::TowerCoords{77, 13});
-	gh[0].push_back(tower);
-
-	return gh;
-}
-
-
 int main(int argc, char** argv) {
-	td::game::World w = GetWorld();
-
 	// init GL context
 	td::Display display(1920, 1080, "Tower-Defense 2");
 
-	td::render::Camera cam;
-
-	display.OnAspectRatioChange.Connect([&cam](float a_AspectRatio) { cam.UpdatePerspective(a_AspectRatio); });
-
-	td::sim::GameHistory gh = GetCustomHistory();
-
-	td::render::RenderPipeline renderer;
-	renderer.AddRenderer<td::render::WorldRenderer>(cam, w);
-	renderer.AddRenderer<td::render::EntityRenderer>(cam, w);
-	renderer.AddRenderer<td::render::TowerRenderer>(cam, w);
-
-	cam.SetCamPos({77, 5, 13});
-	cam.UpdatePerspective(display.GetAspectRatio());
-
-	td::sim::RealTimeSimulation simulation(w, 500);
-
-	display.OnKeyDown.Connect([&simulation](SDL_Keycode key) {
-		if (key == SDLK_A) {
-			auto spawn =
-				std::make_shared<td::protocol::commands::SpawnTroopCommand>(0, 0, td::Vec2fp{td::FpFloat(77), td::FpFloat(13)}, 0);
-			td::Array<td::protocol::LockStep, LOCKSTEP_BUFFER_SIZE> steps{};
-			steps[0].push_back(spawn);
-			td::protocol::packets::LockStepsPacket packet{0, steps};
-			simulation.HandlePacket(packet);
-		}
-	});
+	display.ChangeState<td::MainMenuState>();
 
 	while (!display.IsCloseRequested()) {
 		display.PollEvents();
-		float lerp = simulation.Update();
-		renderer.Render(lerp);
-		display.Update();
+		float delta = GetDelta();
+		display.Update(delta);
 	}
 
 	return 0;

src/server/IServerSocket.cpp

@@ -0,0 +1,31 @@
+#include <server/IServerSocket.h>
+
+namespace td {
+namespace server {
+
+void IServerSocket::OnConnectPeer(PeerID a_PeerId) {
+	m_Ids.AddConnection(a_PeerId);
+	OnConnect(m_Ids.GetPlayerId(a_PeerId));
+}
+
+void IServerSocket::OnDisconnectPeer(PeerID a_PeerId) {
+	OnDisconnect(m_Ids.GetPlayerId(a_PeerId));
+	m_Ids.RemovePeer(a_PeerId);
+}
+
+void IServerSocket::OnReceivePeer(PeerID a_PeerId, const protocol::PacketBase& a_Packet) {
+	OnReceive(m_Ids.GetPlayerId(a_PeerId), a_Packet);
+}
+
+void IServerSocket::Send(PlayerID a_PlayerId, const protocol::PacketBase& a_Packet) {
+	SendPeer(m_Ids.GetPeerId(a_PlayerId), a_Packet);
+}
+
+void IServerSocket::Broadcast(const protocol::PacketBase& a_Packet) {
+	for (auto [peerId, playerId] : m_Ids) {
+		SendPeer(peerId, a_Packet);
+	}
+}
+
+}  // namespace server
+}  // namespace td

src/server/Server.cpp

@@ -0,0 +1,9 @@
+#include <server/Server.h>
+
+namespace td {
+namespace server {
+
+
+
+}  // namespace server
+}  // namespace td

src/server/ServerState.cpp

@@ -0,0 +1,24 @@
+#include <server/ServerState.h>
+#include <server/Server.h>
+
+#include <td/common/StateMachine.h>
+
+namespace td {
+namespace server {
+
+ServerState::ServerState(Server& a_Server) : Server::State(a_Server) {
+	Connect(m_StateMachine.m_Socket->OnReceive, std::bind(&ServerState::HandlePacket, this, std::placeholders::_1, std::placeholders::_2));
+}
+
+ServerState::~ServerState() {}
+
+void ServerState::SendPacket(PlayerID a_Id, const protocol::PacketBase& a_Packet) {
+	m_StateMachine.m_Socket->Send(a_Id, a_Packet);
+}
+
+void ServerState::BroadcastPacket(const protocol::PacketBase& a_Packet) {
+	m_StateMachine.m_Socket->Broadcast(a_Packet);
+}
+
+}  // namespace server
+}  // namespace 

src/server/socket/FakeSocket.cpp

@@ -0,0 +1,48 @@
+#include <server/socket/FakeSocket.h>
+
+namespace td {
+namespace server {
+
+void FakeSocket::SendPeer(PeerID a_Peer, const protocol::PacketBase& a_Packet) {
+	auto socket = m_Clients.at(a_Peer);
+	assert(socket.has_value());
+	assert(!socket.value().expired());
+	socket.value().lock()->OnReceive(a_Packet);
+}
+
+void FakeSocket::ReceiveFromFakePeer(PeerID a_Peer, const protocol::PacketBase& a_Packet) {
+	OnReceivePeer(a_Peer, a_Packet);
+}
+
+PeerID FakeSocket::ConnectFakePeer(const std::shared_ptr<client::FakeSocket>& a_Socket) {
+	int peerId = GetNextFreeId();
+	if (peerId == -1) {
+		peerId = m_Clients.size();
+		m_Clients.push_back(a_Socket);
+	} else {
+		m_Clients.emplace(m_Clients.begin() + peerId, a_Socket);
+	}
+	a_Socket->OnConnect();
+	OnConnectPeer(peerId);
+	return peerId;
+}
+
+void FakeSocket::DisconnectFakePeer(PeerID a_Peer) {
+	auto socket = m_Clients.at(a_Peer);
+	assert(socket.has_value());
+	assert(!socket.value().expired());
+	socket.value().lock()->OnDisconnect();
+	OnDisconnectPeer(a_Peer);
+}
+
+int FakeSocket::GetNextFreeId() {
+	auto it = std::find_if(m_Clients.begin(), m_Clients.end(), [](const auto& a_Value) { return !a_Value.has_value(); });
+
+	if (it == m_Clients.end())
+		return -1;
+
+	return std::distance(m_Clients.begin(), it);
+}
+
+}  // namespace server
+}  // namespace td

src/server/state/GameState.cpp

@@ -0,0 +1,31 @@
+#include <server/state/GameState.h>
+#include <server/state/GameStateHandler.h>
+
+#include <iostream>
+
+namespace td {
+namespace server {
+
+GameState::GameState(Server& a_Server, const std::shared_ptr<game::World>& a_World) : ServerState(a_Server), m_World(a_World), m_Simulation(*m_World, STEP_TIME), m_Time(0) {
+	std::cout << "Switched to Game state !\n";
+	BroadcastPacket(m_Simulation.MakePacket());
+}
+
+void GameState::HandlePacket(PlayerID a_Id, const protocol::PacketBase& a_Packet) {
+	GameStateHandler handler(*this, a_Id);
+	a_Packet.Dispatch(handler);
+}
+
+void GameState::Update(float a_Delta) {
+	// TODO: don't make STEP_TIME constant
+	static const float stepTimeSecond = static_cast<float>(STEP_TIME) / 1000.0f;
+	m_Time += a_Delta;
+	if (m_Time > stepTimeSecond) {
+		m_Time = std::fmod(m_Time, stepTimeSecond);
+		auto lockStepPacket = m_Simulation.Update();
+		BroadcastPacket(lockStepPacket);
+	}
+}
+
+}  // namespace server
+}  // namespace td

src/server/state/GameStateHandler.cpp

@@ -0,0 +1,28 @@
+#include <server/state/GameState.h>
+#include <server/state/GameStateHandler.h>
+
+namespace td {
+namespace server {
+
+GameStateHandler::GameStateHandler(GameState& a_GameState, PlayerID a_PlayerId) : m_GameState(a_GameState), m_PlayerId(a_PlayerId) {}
+
+// TODO: redo this
+void GameStateHandler::Handle(const protocol::packets::SpawnTroopPacket& a_Packet) {
+	static const EntityCoords DEFAULT_POS(td::FpFloat(77), td::FpFloat(13));
+
+	td::protocol::commands::SpawnTroopCommand spawn(*a_Packet->m_Type, *a_Packet->m_Level, DEFAULT_POS, m_PlayerId);
+	m_GameState.m_Simulation.Handle(spawn);
+}
+
+// TODO: and this
+void GameStateHandler::Handle(const protocol::packets::PlaceTowerPacket& a_Packet) {
+	td::protocol::commands::PlaceTowerCommand place(a_Packet->m_Type, m_PlayerId, a_Packet->m_Position);
+	m_GameState.m_Simulation.Handle(place);
+}
+
+void GameStateHandler::Handle(const protocol::packets::LockStepRequestPacket& a_Packet) {
+	m_GameState.SendPacket(m_PlayerId, m_GameState.m_Simulation.GetResponse(a_Packet));
+}
+
+}  // namespace server
+}  // namespace td

src/server/state/LobbyState.cpp

@@ -0,0 +1,18 @@
+#include <server/state/LobbyState.h>
+#include <server/state/GameState.h>
+
+#include <iostream>
+
+namespace td {
+namespace server {
+
+void LobbyState::HandlePacket(PlayerID a_Id, const protocol::PacketBase& a_Packet) {
+
+}
+
+void LobbyState::Update(float a_Delta) {
+	m_StateMachine.ChangeState<GameState>(m_World);
+}
+
+}  // namespace server
+}  // namespace td

src/td/Types.cpp

@@ -2,6 +2,7 @@
 
 #include <sp/common/DataBuffer.h>
 #include <sp/common/ByteSwapping.h>
+#include <sp/common/DataBufferOperators.h>
 
 namespace td {
 

src/td/display/Display.cpp

@@ -1,4 +1,4 @@
-#include <td/input/Display.h>
+#include <td/display/Display.h>
 
 #include <GL/glew.h>
 #include <SDL3/SDL.h>
@@ -38,6 +38,9 @@ Display::Display(int a_Width, int a_Height, const std::string& a_Title) :
 	SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
 	SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 8);
 
+	SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS, 1);
+	SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES, 8);
+
 	m_GLContext = SDL_GL_CreateContext(m_Window);
 
 	if (!m_GLContext) {
@@ -46,6 +49,8 @@ Display::Display(int a_Width, int a_Height, const std::string& a_Title) :
 
 	int major, minor, mask;
 	int r, g, b, a, depth;
+	int mBuffers, mSamples;
+
 	SDL_GL_GetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, &mask);
 	SDL_GL_GetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, &major);
 	SDL_GL_GetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, &minor);
@@ -57,6 +62,9 @@ Display::Display(int a_Width, int a_Height, const std::string& a_Title) :
 
 	SDL_GL_GetAttribute(SDL_GL_DEPTH_SIZE, &depth);
 
+	SDL_GL_GetAttribute(SDL_GL_MULTISAMPLEBUFFERS, &mBuffers);
+	SDL_GL_GetAttribute(SDL_GL_MULTISAMPLESAMPLES, &mSamples);
+
 	const char* mask_desc;
 
 	if (mask & SDL_GL_CONTEXT_PROFILE_CORE) {
@@ -72,6 +80,8 @@ Display::Display(int a_Width, int a_Height, const std::string& a_Title) :
 	utils::LOG(utils::Format(
 		"GL Context : %i.%i %s, Color : R:%i G:%i B:%i A:%i, Depth bits : %i", major, minor, mask_desc, r, g, b, a, depth));
 
+	utils::LOG(utils::Format("MultiSamples : Buffers : %i, Samples : %i", mBuffers, mSamples));
+
 	SDL_GL_MakeCurrent(m_Window, m_GLContext);
 
 	GLenum error = glewInit();
@@ -81,6 +91,9 @@ Display::Display(int a_Width, int a_Height, const std::string& a_Title) :
 
 	// WindowResizeEvent(WindowWidth, WindowHeight);
 
+	// vsync
+	SDL_GL_SetSwapInterval(1);
+
 	// Setup Dear ImGui context
 	IMGUI_CHECKVERSION();
 	ImGui::CreateContext();
@@ -111,6 +124,9 @@ Display::Display(int a_Width, int a_Height, const std::string& a_Title) :
 	ImGui_ImplOpenGL3_Init("#version 330");
 }
 
+void Display::Close() {
+	m_ShouldClose = true;
+}
 
 void Display::PollEvents() {
 	SDL_Event event;
@@ -131,7 +147,7 @@ void Display::PollEvents() {
 			}
 
 			case SDL_EVENT_KEY_DOWN: {
-				if(!event.key.repeat)
+				if (!event.key.repeat)
 					OnKeyDown(event.key.key);
 				break;
 			}
@@ -147,7 +163,11 @@ void Display::PollEvents() {
 	ImGui::NewFrame();
 }
 
-void Display::Update() {
+void Display::Update(float a_Delta) {
+	StateMachine::Update(a_Delta);
+#ifndef NDEBUG
+	ImGui::ShowDemoWindow();
+#endif
 	ImGui::Render();
 	ImGuiIO& io = ImGui::GetIO();
 	glViewport(0, 0, (int)io.DisplaySize.x, (int)io.DisplaySize.y);

src/td/display/DisplayState.cpp

@@ -0,0 +1,10 @@
+#include <td/display/DisplayState.h>
+
+namespace td {
+
+DisplayState::DisplayState(Display& a_Display) : Display::State(a_Display) {
+	Connect(m_StateMachine.OnKeyDown, std::bind(&DisplayState::OnKeyDown, this, std::placeholders::_1));
+	Connect(m_StateMachine.OnAspectRatioChange, std::bind(&DisplayState::OnAspectRatioChange, this, std::placeholders::_1));
+}
+
+}  // namespace td

src/td/display/menu/CreatePartyMenu.cpp

@@ -0,0 +1,16 @@
+#include <td/display/menu/CreatePartyMenu.h>
+
+#include <imgui.h>
+
+namespace td {
+
+CreatePartyMenu::CreatePartyMenu(MainMenuState& a_MainMenu) : MainMenuState::Menu(a_MainMenu) {}
+
+CreatePartyMenu::~CreatePartyMenu() {}
+
+void CreatePartyMenu::Update() {
+	ImGui::Text("CreatePartyMenu");
+	m_StateStack.RenderBackButton();
+}
+
+}  // namespace td

src/td/display/menu/JoinPartyMenu.cpp

@@ -0,0 +1,16 @@
+#include <td/display/menu/JoinPartyMenu.h>
+
+#include <imgui.h>
+
+namespace td {
+
+JoinPartyMenu::JoinPartyMenu(MainMenuState& a_MainMenu) : MainMenuState::Menu(a_MainMenu) {}
+
+JoinPartyMenu::~JoinPartyMenu() {}
+
+void JoinPartyMenu::Update() {
+	ImGui::Text("JoinPartyMenu");
+	m_StateStack.RenderBackButton();
+}
+
+}  // namespace td

src/td/display/menu/MainMenu.cpp

@@ -0,0 +1,28 @@
+#include <td/display/menu/MainMenu.h>
+
+#include <imgui.h>
+#include <td/display/menu/CreatePartyMenu.h>
+#include <td/display/menu/JoinPartyMenu.h>
+#include <td/display/menu/SettingsMenu.h>
+#include <td/display/state/DebugWorldState.h>
+
+namespace td {
+
+MainMenu::MainMenu(MainMenuState& a_MainMenu) : MainMenuState::Menu(a_MainMenu) {}
+
+MainMenu::~MainMenu() {}
+
+void MainMenu::Update() {
+	if (ImGui::Button("Create Party"))
+		m_StateStack.PushState<CreatePartyMenu>();
+	if (ImGui::Button("Join Party"))
+		m_StateStack.PushState<JoinPartyMenu>();
+	if (ImGui::Button("Settings"))
+		m_StateStack.PushState<SettingsMenu>();
+#ifndef NDEBUG
+	if (ImGui::Button("Debug world"))
+		m_StateStack.ChangeState<DebugWorldState>();
+#endif
+}
+
+}  // namespace td

src/td/display/menu/SettingsMenu.cpp

@@ -0,0 +1,16 @@
+#include <td/display/menu/SettingsMenu.h>
+
+#include <imgui.h>
+
+namespace td {
+
+SettingsMenu::SettingsMenu(MainMenuState& a_MainMenu) : MainMenuState::Menu(a_MainMenu) {}
+
+SettingsMenu::~SettingsMenu() {}
+
+void SettingsMenu::Update() {
+	ImGui::Text("SettingsMenu");
+	m_StateStack.RenderBackButton();
+}
+
+}  // namespace td

src/td/display/state/DebugWorldState.cpp

@@ -0,0 +1,134 @@
+#include <td/display/state/DebugWorldState.h>
+
+#include <chrono>
+#include <fstream>
+#include <iostream>
+
+#include <td/game/World.h>
+#include <td/protocol/packet/PacketSerialize.h>
+#include <td/protocol/packet/Packets.h>
+#include <td/render/renderer/EntityRenderer.h>
+#include <td/render/renderer/TowerRenderer.h>
+#include <td/render/renderer/WorldRenderer.h>
+
+#include <sp/common/DataBuffer.h>
+#include <sp/extensions/Compress.h>
+#include <sp/io/MessageStream.h>
+#include <sp/io/StdIo.h>
+
+#include <server/Server.h>
+#include <server/socket/FakeSocket.h>
+#include <server/state/GameState.h>
+
+#include <client/Client.h>
+#include <client/socket/FakeSocket.h>
+#include <client/state/GameState.h>
+
+#include <td/display/Display.h>
+#include <td/display/state/DebugWorldState.h>
+
+namespace td {
+
+// TODO: get rid of this class
+class WorldApply : public protocol::PacketHandler {
+  private:
+	game::World& m_World;
+	using protocol::PacketHandler::Handle;
+
+  public:
+	WorldApply(game::World& a_World) : m_World(a_World) {}
+
+	void Handle(const protocol::packets::WorldHeaderPacket& a_Header) override {
+		m_World.LoadMap(*a_Header);
+	}
+
+	void Handle(const protocol::packets::WorldDataPacket& a_Data) override {
+		m_World.LoadMap(*a_Data);
+	}
+};
+
+void Save(const protocol::PacketBase& header, const protocol::PacketBase& data) {
+	auto comp = std::make_shared<sp::ZlibCompress>();
+
+	std::ofstream fStream("test/tdmap.tdmap3");
+	auto out = std::make_shared<sp::StdOuput>(fStream);
+
+	sp::MessageStream<protocol::PacketFactory> stream(std::move(out), std::move(comp));
+
+	stream.WriteMessage(header, false);
+	stream.WriteMessage(data, false);
+}
+
+game::WorldPtr GetWorld() {
+	auto comp = std::make_shared<sp::ZlibCompress>();
+
+	std::ifstream fStream("test/tdmap.tdmap2");
+	auto out = std::make_shared<sp::StdInput>(fStream);
+
+	sp::MessageStream<protocol::PacketFactory> stream(std::move(out), std::move(comp));
+
+	auto header = stream.ReadMessage(protocol::PacketID::WorldHeader);
+	auto data = stream.ReadMessage(protocol::PacketID::WorldData);
+
+	auto w = std::make_shared<game::World>();
+	auto wa = std::make_shared<WorldApply>(*w);
+
+	protocol::PacketDispatcher d;
+	d.RegisterHandler(wa);
+
+	d.Dispatch(*header);
+	d.Dispatch(*data);
+
+	Save(*header, *data);
+
+	return w;
+}
+
+DebugWorldState::DebugWorldState(Display& a_Display) : DisplayState(a_Display) {
+	// server
+	game::WorldPtr serverWorld = GetWorld();
+	auto serverFakeSocket = std::make_shared<server::FakeSocket>();
+	m_Server = std::make_unique<server::Server>(serverFakeSocket);
+
+	// client
+	game::WorldPtr clientWorld = GetWorld();
+	auto clientFakeSocket = client::FakeSocket::Connect(serverFakeSocket);
+	m_Client = std::make_unique<client::Client>(clientFakeSocket);
+
+	// render
+	m_Renderer.AddRenderer<render::WorldRenderer>(m_Camera, *clientWorld);
+	m_Renderer.AddRenderer<render::EntityRenderer>(m_Camera, *clientWorld);
+	m_Renderer.AddRenderer<render::TowerRenderer>(m_Camera, *clientWorld);
+
+	// camera
+	m_Camera.SetCamPos({77, 7, 13});
+	m_Camera.UpdatePerspective(m_StateMachine.GetAspectRatio());
+
+	// states
+	m_ClientState = m_Client->ChangeState<client::GameState>(clientWorld, STEP_TIME);
+	m_Server->ChangeState<server::GameState>(serverWorld);
+}
+
+void DebugWorldState::Update(float a_Delta) {
+	m_Server->Update(a_Delta);
+	m_Client->Update(a_Delta);
+	// TODO: m_ClientState might be invalid !
+	m_Renderer.Render(m_ClientState->GetCurrentLerp());
+}
+
+void DebugWorldState::OnAspectRatioChange(float a_Ratio) {
+	m_Camera.UpdatePerspective(a_Ratio);
+}
+
+void DebugWorldState::OnKeyDown(SDL_Keycode a_Key) {
+	// temporary tests
+	if (a_Key == SDLK_A) {
+		m_Client->SendPacket(td::protocol::packets::SpawnTroopPacket(td::EntityType::Zombie, 1));
+	} else if (a_Key == SDLK_Z) {
+		m_Client->SendPacket(td::protocol::packets::PlaceTowerPacket(td::TowerType::Archer, td::TowerCoords(77, 13)));
+	}
+}
+
+DebugWorldState::~DebugWorldState() {}
+
+}  // namespace td

src/td/display/state/MainMenuState.cpp

@@ -0,0 +1,31 @@
+#include <td/display/state/MainMenuState.h>
+
+#include <imgui.h>
+#include <td/display/menu/MainMenu.h>
+#include <td/display/state/DebugWorldState.h>
+
+namespace td {
+
+MainMenuState::MainMenuState(Display& a_Display) : DisplayState(a_Display) {
+	PushState<MainMenu>();
+}
+
+MainMenuState::~MainMenuState() {}
+
+void MainMenuState::Update(float a_Delta) {
+	ImGui::Begin("MainWindow");
+	MainMenuStateStack::Update();
+	ImGui::End();
+}
+
+void MainMenuState::RenderBackButton() {
+	if (ImGui::Button("Back"))
+		PopState();
+}
+
+void MainMenuState::OnKeyDown(SDL_Keycode a_Key) {
+	if (a_Key == SDLK_ESCAPE)
+		PopState();
+}
+
+}  // namespace td

src/td/protocol/packet/ChunkSerialize.cpp

@@ -3,17 +3,7 @@
 namespace td {
 namespace game {
 
-sp::DataBuffer& operator<<(sp::DataBuffer& a_Buffer, const ChunkPtr& a_Chunk) {
-	a_Buffer << a_Chunk->m_Palette;
-	a_Buffer << a_Chunk->m_Data;
-	return a_Buffer;
-}
 
-sp::DataBuffer& operator>>(sp::DataBuffer& a_Buffer, ChunkPtr& a_Chunk) {
-	a_Chunk = std::make_shared<td::game::Chunk>();
-	a_Buffer >> a_Chunk->m_Palette;
-	return a_Buffer >> a_Chunk->m_Data;
-}
 
 } // namespace game
 } // namespace td

src/td/protocol/packet/PacketSerialize.cpp

@@ -1,6 +1,8 @@
 #include <td/protocol/packet/PacketData.h>
 #include <td/protocol/packet/PacketSerialize.h>
 
+#include <sp/common/DataBufferOperators.h>
+
 namespace td {
 namespace game {
 
@@ -15,5 +17,17 @@ sp::DataBuffer& operator>>(sp::DataBuffer& a_Buffer, TeamCastle& a_Castle) {
 	return a_Buffer;
 }
 
+sp::DataBuffer& operator<<(sp::DataBuffer& a_Buffer, const Spawn& a_Spawn) {
+	return a_Buffer << a_Spawn.GetCenterX() << a_Spawn.GetCenterY();
+}
+
+sp::DataBuffer& operator>>(sp::DataBuffer& a_Buffer, Spawn& a_Spawn) {
+	float x, y;
+	a_Buffer >> x >> y;
+	a_Spawn.SetCenter({x, y});
+	return a_Buffer;
+}
+
+
 }  // namespace game
 }  // namespace td

src/td/render/loader/WorldLoader.cpp

@@ -27,7 +27,7 @@ GL::VertexArray LoadWorldModel(const td::game::World* world) {
 				td::game::TileIndex tileIndex = chunk->GetTileIndex(tileNumber);
 				td::game::TilePtr tile = world->GetTilePtr(tileIndex);
 
-				if (tile == nullptr)
+				if (!tile)
 					continue;
 
 				positions.insert(

src/td/render/renderer/WorldRenderer.cpp

@@ -16,7 +16,6 @@ WorldRenderer::~WorldRenderer() {}
 void WorldRenderer::Render(float a_Lerp) {
 	m_Shader->Start();
 	Renderer::Render(*m_WorldVao);
-	ImGui::ShowDemoWindow();
 }
 
 }  // namespace render

src/td/simulation/ClientSimulation.cpp

@@ -0,0 +1,126 @@
+#include <td/simulation/ClientSimulation.h>
+
+#include <chrono>
+
+#include <iostream>
+
+// TODO: mutex this bad boy
+
+namespace td {
+namespace sim {
+
+const protocol::LockStep ClientSimulation::EMPTY_LOCKSTEP;
+
+std::uint64_t GetTime() {
+	return static_cast<std::uint64_t>(
+		std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::system_clock().now().time_since_epoch()).count());
+}
+
+ClientSimulation::ClientSimulation(std::shared_ptr<game::World> a_World, GameHistory&& a_History, std::uint64_t a_StepTime) :
+	m_StepTime(a_StepTime),
+	m_World(a_World),
+	m_CurrentTime(0),
+	m_CurrentStep(0),
+	m_LastSnapshot(std::make_shared<WorldSnapshot>()),
+	m_LastValidStep(0) {
+	m_History.reserve(a_History.size());
+	for (auto&& lockstep : a_History) {
+		m_History.emplace_back(std::move(lockstep));
+	}
+	Step();
+}
+
+ClientSimulation::ClientSimulation(std::shared_ptr<game::World> a_World, std::uint64_t a_StepTime) :
+	m_StepTime(a_StepTime),
+	m_World(a_World),
+	m_History(std::numeric_limits<StepTime>::max()),
+	m_CurrentTime(0),
+	m_CurrentStep(0),
+	m_LastSnapshot(std::make_shared<WorldSnapshot>()),
+	m_LastValidStep(0) {}
+
+float ClientSimulation::Update(float a_Delta) {
+	// TODO: handle freezes (m_CurrentTime > 2 * m_StepTime)
+	static const float stepTimeSecond = static_cast<float>(m_StepTime) / 1000.0f;
+	m_CurrentTime += a_Delta;
+	if (m_CurrentTime > stepTimeSecond) {
+		m_CurrentTime = std::fmod(m_CurrentTime, stepTimeSecond);
+		Step();
+	}
+	return (float)m_CurrentTime / stepTimeSecond;
+}
+
+bool ClientSimulation::Step() {
+	const auto& step = m_History[m_CurrentStep];
+	if (step.has_value()) {
+		auto snapshot = m_World->Tick(step.value(), FpFloat(m_StepTime) / FpFloat(1000));
+		if (m_LastValidStep + 1 == m_CurrentStep) {
+			m_LastValidStep = m_CurrentStep;
+			m_LastSnapshot = snapshot;
+		}
+	} else {
+		m_World->Tick(EMPTY_LOCKSTEP, FpFloat(m_StepTime) / FpFloat(1000));
+		std::cout << "Empty tick (" << m_CurrentStep << ") !\n";
+	}
+	m_CurrentStep++;
+	return step.has_value();
+}
+
+void ClientSimulation::Handle(const protocol::packets::LockStepsPacket& a_LockSteps) {
+	const auto& steps = a_LockSteps->m_LockSteps;
+	for (std::size_t i = 0; i < LOCKSTEP_BUFFER_SIZE; i++) {
+		m_History[a_LockSteps->m_FirstFrameNumber + i] = steps[i];
+	}
+
+	// to be in the state [0-1]
+	if (a_LockSteps->m_FirstFrameNumber == 0)
+		Step();
+
+	FastReplay();
+}
+
+void ClientSimulation::Handle(const protocol::packets::LockStepResponsePacket& a_LockSteps) {
+	for (const auto& [stepTime, lockStep] : a_LockSteps->m_Steps) {
+		m_History[stepTime] = lockStep;
+	}
+	FastReplay();
+}
+
+std::size_t ClientSimulation::FastForward(std::size_t a_Count) {
+	std::size_t stepCount;
+	bool hasMissingStep = false;
+	for (std::size_t i = 0; i < a_Count; i++) {
+		if (!Step() && !hasMissingStep) {
+			hasMissingStep = true;
+			stepCount = i + 1;
+		}
+	}
+	std::cout << "Was behind " << (hasMissingStep ? stepCount : a_Count) << " ticks !\n";
+	return hasMissingStep ? stepCount : a_Count;
+}
+
+void ClientSimulation::FastReplay() {
+	if (m_LastValidStep + 1 >= m_CurrentStep)
+		return;
+
+	m_World->ResetSnapshots(m_LastSnapshot, m_LastSnapshot);
+
+	const std::size_t stepCount = m_CurrentStep - m_LastValidStep;
+	m_CurrentStep = m_LastValidStep;
+
+	if (FastForward(stepCount) == stepCount)
+		return;
+
+	std::vector<StepTime> missingSteps;
+	missingSteps.reserve(stepCount);
+
+	for (StepTime step = m_LastValidStep + 1; step < m_CurrentStep; step++) {
+		if (!m_History[step].has_value())
+			missingSteps.push_back(step);
+	}
+
+	OnMissingLockSteps(missingSteps);
+}
+
+}  // namespace sim
+}  // namespace td

src/td/simulation/GameHistory.cpp

@@ -1,44 +0,0 @@
-#include <td/simulation/GameHistory.h>
-
-namespace td {
-namespace game {
-
-GameHistory::GameHistory() : m_History(std::numeric_limits<HistorySizeType>::max()), m_Cursor(0) {}
-
-void GameHistory::SetLockStep(HistorySizeType a_Index, protocol::LockStep&& a_LockStep) {
-	m_History[a_Index] = std::move(a_LockStep);
-}
-
-const protocol::LockStep& GameHistory::GetLockStep(HistorySizeType a_Index) const {
-	return *m_History[a_Index];
-}
-
-bool GameHistory::HasLockStep(HistorySizeType a_Index) const {
-	return m_History[a_Index].has_value();
-}
-
-const protocol::LockStep& GameHistory::GetNextStep() {
-	return GetLockStep(m_Cursor++);
-}
-
-bool GameHistory::HasNextStep() const {
-	return HasLockStep(m_Cursor);
-}
-
-void GameHistory::FromPacket(protocol::pdata::LockSteps&& a_Steps) {
-	for (int i = 0; i < LOCKSTEP_BUFFER_SIZE; i++) {
-		protocol::LockStep& step = a_Steps.m_LockSteps[i];
-		SetLockStep(i + a_Steps.m_FirstFrameNumber, std::move(step));
-	}
-}
-
-protocol::packets::LockStepsPacket GameHistory::ToPacket(HistorySizeType a_StartIndex) {
-	Array<protocol::LockStep, LOCKSTEP_BUFFER_SIZE> steps;
-	for (int i = 0; i < LOCKSTEP_BUFFER_SIZE; i++) {
-		steps[i] = GetLockStep(a_StartIndex + i);
-	}
-	return {a_StartIndex, std::move(steps)};
-}
-
-}  // namespace game
-}  // namespace td

src/td/simulation/RealTimeSimulation.cpp

@@ -1,93 +0,0 @@
-#include <td/simulation/RealTimeSimulation.h>
-
-#include <chrono>
-
-namespace td {
-namespace sim {
-
-const protocol::LockStep RealTimeSimulation::EMPTY_LOCKSTEP;
-
-std::uint64_t GetTime() {
-	return static_cast<std::uint64_t>(
-		std::chrono::duration_cast<std::chrono::milliseconds>(std::chrono::system_clock().now().time_since_epoch()).count());
-}
-
-RealTimeSimulation::RealTimeSimulation(game::World& a_World, const GameHistory& a_History, std::uint64_t a_StepTime) :
-	m_StepTime(a_StepTime),
-	m_World(a_World),
-	m_CurrentTime(0),
-	m_LastTime(GetTime()),
-	m_CurrentStep(0),
-	m_LastSnapshot(std::make_shared<WorldSnapshot>()),
-	m_LastValidStep(0) {
-	m_History.reserve(a_History.size());
-	for (const auto& lockstep : a_History) {
-		m_History.emplace_back(lockstep);
-	}
-	Step();
-}
-
-RealTimeSimulation::RealTimeSimulation(game::World& a_World, std::uint64_t a_StepTime) :
-	m_StepTime(a_StepTime),
-	m_World(a_World),
-	m_History(std::numeric_limits<std::uint16_t>::max()),
-	m_CurrentTime(0),
-	m_LastTime(GetTime()),
-	m_CurrentStep(0),
-	m_LastSnapshot(std::make_shared<WorldSnapshot>()),
-	m_LastValidStep(0) {
-	Step();
-}
-
-float RealTimeSimulation::Update() {
-	// TODO: handle freezes (m_CurrentTime > 2 * m_StepTime)
-	m_CurrentTime += GetTime() - m_LastTime;
-	m_LastTime = GetTime();
-	if (m_CurrentTime > m_StepTime) {
-		Step();
-		m_CurrentTime -= m_StepTime;
-	}
-	return (float)m_CurrentTime / (float)m_StepTime;
-}
-
-void RealTimeSimulation::Step() {
-	const auto& step = m_History[m_CurrentStep];
-	if (step.has_value()) {
-		m_LastSnapshot = m_World.Tick(step.value(), FpFloat(m_StepTime) / FpFloat(1000));
-		m_LastValidStep = m_CurrentStep;
-	} else {
-		m_World.Tick(EMPTY_LOCKSTEP, FpFloat(m_StepTime) / FpFloat(1000));
-	}
-	m_CurrentStep++;
-}
-
-void RealTimeSimulation::HandlePacket(const protocol::packets::LockStepsPacket& a_LockSteps) {
-	const auto& steps = a_LockSteps->m_LockSteps;
-	for (std::size_t i = 0; i < LOCKSTEP_BUFFER_SIZE; i++) {
-		m_History[a_LockSteps->m_FirstFrameNumber + i] = steps[i];
-	}
-	FastReplay();
-}
-
-void RealTimeSimulation::HandlePacket(const protocol::packets::PredictCommandPacket& a_Predict) {}
-
-void RealTimeSimulation::FastForward(std::size_t a_Count) {
-	for (std::size_t i = 0; i < a_Count; i++) {
-		Step();
-	}
-}
-
-void RealTimeSimulation::FastReplay() {
-	if (m_LastValidStep >= m_CurrentStep)
-		return;
-
-	m_World.ResetSnapshots(m_LastSnapshot, m_LastSnapshot);
-
-	const std::size_t stepCount = m_CurrentStep - m_LastValidStep;
-	m_CurrentStep = m_LastValidStep;
-	
-	FastForward(stepCount);
-}
-
-}  // namespace sim
-}  // namespace td

src/td/simulation/ServerSimulation.cpp

@@ -0,0 +1,52 @@
+#include <td/simulation/ServerSimulation.h>
+
+namespace td {
+namespace sim {
+
+ServerSimulation::ServerSimulation(game::World& a_World, std::uint64_t a_StepTime) :
+	m_World(a_World), m_StepTime(a_StepTime), m_CurrentTime(0), m_History(std::numeric_limits<StepTime>::max()) {}
+
+protocol::packets::LockStepsPacket ServerSimulation::Update() {
+	std::lock_guard<std::mutex> lock(m_Mutex);
+
+	m_World.Tick(m_History[m_CurrentTime], FpFloat(m_StepTime) / FpFloat(1000));
+	m_CurrentTime++;
+
+	return MakePacket();
+}
+
+protocol::packets::LockStepsPacket ServerSimulation::MakePacket() {
+	std::array<protocol::LockStep, LOCKSTEP_BUFFER_SIZE> nextSteps;
+	std::copy(m_History.begin() + m_CurrentTime, m_History.begin() + m_CurrentTime + nextSteps.size(), nextSteps.begin());
+	return {m_CurrentTime, std::move(nextSteps)};
+}
+
+template <typename T>
+void AddToCommandHistory(protocol::LockStep& a_LockStep, const T& a_Cmd) {
+	a_LockStep.push_back({std::make_shared<T>(a_Cmd)});
+}
+
+void ServerSimulation::Handle(const protocol::commands::SpawnTroopCommand& a_SpawnTroop) {
+	std::lock_guard<std::mutex> lock(m_Mutex);
+	AddToCommandHistory(m_History[m_CurrentTime + LOCKSTEP_BUFFER_SIZE], a_SpawnTroop);
+}
+
+void ServerSimulation::Handle(const protocol::commands::PlaceTowerCommand& a_PlaceTower) {
+	std::lock_guard<std::mutex> lock(m_Mutex);
+	AddToCommandHistory(m_History[m_CurrentTime + LOCKSTEP_BUFFER_SIZE], a_PlaceTower);
+}
+
+protocol::packets::LockStepResponsePacket ServerSimulation::GetResponse(
+	const protocol::packets::LockStepRequestPacket& a_Missing) const {
+	std::map<StepTime, protocol::LockStep> result;
+
+	for (StepTime step : a_Missing->m_Missing) {
+		result.emplace(step, m_History[step]);
+	}
+
+	return {result};
+}
+
+
+}  // namespace sim
+}  // namespace td

xmake.lua

@@ -3,8 +3,7 @@ add_rules("mode.debug", "mode.release")
 add_repositories("persson-repo https://git.ale-pri.com/Persson-dev/xmake-repo.git")
 
 add_requires("imgui 1.92.0", {configs = {sdl3 = true, opengl3 = true}})
-add_requires("splib 2.1.0", "zlib")
-add_requires("libsdl3 3.2.16", "glew", "fpm", "enet6")
+add_requires("libsdl3 3.2.16", "splib 2.3.0", "zlib", "glew", "fpm", "enet6")
 
 set_languages("c++17")