Hierarchical Final State Machine

About Hierarchical Final State Machine HFSM (Hierarchical Finite State Machine) is a simple and flexible library for building state machines in C#. The library provides an easy-to-use API for defining states, transitions, and hierarchical relationships between states. Feature - Define states with custom behavior (OnEnter, OnUpdate, OnExit) - Define transitions based on events and/or guard conditions - Hierarchical state organization - State machine builder for easy construction and configuration - Event-driven state updates Exemple of usage - Fictionnal // Define your state and event enums public enum MyState { Root, Idle, Walk, Run } public enum MyEvent { FreezePlayer , StartRun} private HFSM m_hfsm; private void BuildHFSM() { // Create a new HFSMBuilder instance var builder = new HFSMBuilder(); // Add states to the builder builder.AddState(MyState.Movement); builder.AddState(MyState.Idle, MyState.Movement); builder.AddState(MyState.Walk, MyState.Movement, OnStartWalk, OnUpdateWalk, OnExitWalk); builder.AddState(MyState.Run, MyState.Movement); builder.AddState(MyState.Freeze, OnEnterFreeze); //// Define transitions between states // Can use a guard builder.AddTransition(MyState.Idle, MyState.Walk, () => IsMoving); // An event builder.AddTransition(MyState.Movement, MyState.Freeze, MyEvent.FreezePlayer); // Or both builder.AddTransition(MyState.Walk, MyState.Run, () => Pawn.Velocity > 15, MyEvent.StartRun); // Build the state machine var hfsm = builder.Build(); } protected override void OnActivate() { BuildHFSM(); base.OnActivate(); } [GameEvent.Tick] private void OnUpdate() { // Update the state machine m_hfsm.Update(); } private void OnStartWalk() { Log.Info("I'm walking!") } private void OnUpdateWalk() { // Do stuff } private void OnExitWalk() { // Do stuff } private void OnEnterFreeze() { Log.Info("It's getting cold in there!") } protected override void OnDeactivate() { // Stop the state machine m_hfsm.Stop(); } Another exemple - Movement controller public partial class MovementsController : EntityComponent { private void BuildHFSM() { HFSMBuilder builder = new HFSMBuilder(); builder.AddState( States.OnGroundState , OnEnterGroundState, OnUpdateGroundState, OnExitGroundState); { builder.AddState( States.JogState ,States.OnGroundState, OnEnterJogState); { builder.AddTransition( States.JogState, States.RunState , () => Input.Down( "run" )); builder.AddTransition( States.JogState, States.WalkState , () => Input.Down( "walk" )); builder.AddTransition( States.JogState, States.DuckState , () => Input.Down( "duck" )); } builder.AddState( States.RunState ,States.OnGroundState, OnEnterSprintState); { builder.AddTransition( States.RunState, States.JogState , () => !Input.Down( "run" )); builder.AddTransition( States.RunState, States.WalkState , () => Input.Down( "walk" )); builder.AddTransition( States.RunState, States.DuckState , () => Input.Down( "duck" )); } builder.AddState( States.WalkState ,States.OnGroundState, OnEnterWalkState); { builder.AddTransition( States.WalkState, States.JogState , () => !Input.Down( "walk" )); builder.AddTransition( States.WalkState, States.DuckState , () => Input.Down( "duck" )); } builder.AddState( States.DuckState, States.OnGroundState, OnEnterDuckState, null , OnExitDuckState); { builder.AddTransition( States.DuckState, States.JogState , () => !Input.Down( "duck" ) && CanUnduck()); } builder.AddTransition( States.OnGroundState, States.InAirState , () => !Grounded); } builder.AddState( States.InAirState , OnEnterAirState, OnUpdateAirState, OnExitAirState); { builder.AddTransition( States.InAirState, States.DuckState , () => Input.Down( "duck" ) && Grounded ); builder.AddTransition( States.InAirState, States.OnGroundState , () => Grounded ); } m_hfsm = builder.Build(); } } }