add StateMachine

include/td/common/StateMachine.h

@@ -0,0 +1,39 @@
+#pragma once
+
+#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;
+
+	  protected:
+		TDerived& m_StateMachine;
+	};
+
+	StateMachine() {}
+	virtual ~StateMachine() {}
+
+	TReturn Update(TArgs... args) {
+		assert(m_State);
+		return m_State->Update(args...);
+	}
+
+	template <typename T, typename... Args>
+	void ChangeState(Args&&... args) {
+		m_State = std::make_unique<T>(static_cast<TDerived&>(*this), args...);
+	}
+
+  private:
+	std::unique_ptr<State> m_State;
+};
+
+
+}  // namespace td

include/td/simulation/ClientSimulation.h

@@ -16,8 +16,7 @@ class ClientSimulation : public protocol::PacketHandler {
 	std::uint64_t m_StepTime;
 	game::World& m_World;
 	GameBuffer m_History;
-	std::uint64_t m_CurrentTime;
-	std::uint64_t m_LastTime;
+	float m_CurrentTime;
 	StepTime m_CurrentStep;
 
 	std::shared_ptr<WorldSnapshot> m_LastSnapshot;
@@ -45,7 +44,7 @@ class ClientSimulation : public protocol::PacketHandler {
 	/**
 	 * \return the progress [0-1] between two steps
 	 */
-	float Update();
+	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;