add (very) basic main menu

include/td/common/StateMachine.h

@@ -1,7 +1,7 @@
 #pragma once
 
-#include <memory>
 #include <cassert>
+#include <memory>
 
 namespace td {
 
@@ -15,6 +15,11 @@ class StateMachine {
 
 		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;
 	};

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/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/MainMenuState.h

@@ -1,15 +1,27 @@
 #pragma once
 
+#include <td/common/StateStack.h>
 #include <td/display/DisplayState.h>
 
 namespace td {
 
-class MainMenuState : public DisplayState {
+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