state machines

Characters/Character.cs

@@ -1,5 +1,4 @@
 using Godot;
-using System;
 
 namespace SupaLidlGame.Characters
 {
@@ -16,17 +15,35 @@ namespace SupaLidlGame.Characters
         // Get the gravity from the project settings to be synced with RigidBody nodes.
         public float Gravity = ProjectSettings.GetSetting("physics/2d/default_gravity").AsSingle();
 
-        public Vector2 Direction { get; protected set; } = Vector2.Zero;
+        public Vector2 Direction { get; set; } = Vector2.Zero;
+
+        public Vector2 Target { get; set; } = Vector2.Zero;
+
+        [Export]
+        public State.Machine StateMachine { get; set; }
 
         public override void _Process(double delta)
         {
+            if (StateMachine != null)
+            {
+                StateMachine.Process(delta);
+            }
+        }
+
+        public override void _Input(InputEvent @event)
+        {
+            if (StateMachine != null)
+            {
+                StateMachine.Input(@event);
+            }
         }
 
         public override void _PhysicsProcess(double delta)
         {
-            // movement would be more crisp with no acceleration
+            if (StateMachine != null)
-            Velocity = Direction * Speed;
+            {
-            MoveAndSlide();
+                StateMachine.PhysicsProcess(delta);
+            }
         }
     }
 }

Characters/ExampleEnemy.tscn

@@ -1,14 +1,18 @@
-[gd_scene load_steps=4 format=3 uid="uid://dymwd5ihpwyqm"]
+[gd_scene load_steps=7 format=3 uid="uid://dymwd5ihpwyqm"]
 
 [ext_resource type="Script" path="res://Characters/NPC.cs" id="1_4x3dm"]
 [ext_resource type="Texture2D" uid="uid://bw052v8ikfget" path="res://icon.svg" id="2_ujqd7"]
+[ext_resource type="Script" path="res://Characters/States/Machine.cs" id="3_k4ypw"]
+[ext_resource type="Script" path="res://Characters/States/NPCIdleState.cs" id="4_8r2qn"]
+[ext_resource type="Script" path="res://Characters/States/NPCMoveState.cs" id="5_utogm"]
 
 [sub_resource type="RectangleShape2D" id="RectangleShape2D_uict5"]
 size = Vector2(32, 16)
 
-[node name="ExampleEnemy" type="CharacterBody2D"]
+[node name="ExampleEnemy" type="CharacterBody2D" node_paths=PackedStringArray("StateMachine")]
 script = ExtResource("1_4x3dm")
 Speed = 32.0
+StateMachine = NodePath("StateMachine")
 
 [node name="Icon" type="Sprite2D" parent="."]
 scale = Vector2(0.25, 0.25)
@@ -17,3 +21,16 @@ texture = ExtResource("2_ujqd7")
 [node name="CollisionShape2D" type="CollisionShape2D" parent="."]
 position = Vector2(0, 8)
 shape = SubResource("RectangleShape2D_uict5")
+
+[node name="StateMachine" type="Node" parent="." node_paths=PackedStringArray("InitialState", "Character")]
+script = ExtResource("3_k4ypw")
+InitialState = NodePath("Idle")
+Character = NodePath("..")
+
+[node name="Idle" type="Node" parent="StateMachine" node_paths=PackedStringArray("MoveState")]
+script = ExtResource("4_8r2qn")
+MoveState = NodePath("../Move")
+
+[node name="Move" type="Node" parent="StateMachine" node_paths=PackedStringArray("IdleState")]
+script = ExtResource("5_utogm")
+IdleState = NodePath("../Idle")

Characters/NPC.cs

@@ -8,9 +8,8 @@ namespace SupaLidlGame.Characters
         /// <summary>
         /// Time in seconds it takes for the NPC to think FeelsDankCube
         /// </summary>
-        public const float ThinkTime = 0.125f;
+        public const float ThinkTime = 0.25f;
 
-        public Character Target { get; protected set; }
         public float[] Weights => _weights;
 
         float[] _weights = new float[16];
@@ -30,6 +29,7 @@ namespace SupaLidlGame.Characters
             }
         }
 
+        /*
         public override void _Process(double delta)
         {
             if ((_thinkTimeElapsed += delta) > ThinkTime)
@@ -42,6 +42,7 @@ namespace SupaLidlGame.Characters
             //Direction = (Target.GlobalPosition - GlobalPosition).Normalized();
             base._Process(delta);
         }
+        */
 
         public override void _Draw()
         {
@@ -83,10 +84,21 @@ namespace SupaLidlGame.Characters
             return bestChar;
         }
 
+        public void ThinkProcess(double delta)
+        {
+            if ((_thinkTimeElapsed += delta) > ThinkTime)
+            {
+                _thinkTimeElapsed = 0;
+                Think();
+            }
+
+            Direction = _weightDirs[_bestWeightIdx];
+        }
+
         private void Think()
         {
             Vector2 pos = FindBestTarget().GlobalPosition;
-            Vector2 dir = GlobalPosition.DirectionTo(pos);
+            Vector2 dir = Target = GlobalPosition.DirectionTo(pos);
             float dist = GlobalPosition.DistanceSquaredTo(pos);
 
             for (int i = 0; i < 16; i++)
@@ -99,9 +111,9 @@ namespace SupaLidlGame.Characters
                 Vector2 rotatedDir = new Vector2(-dir.y, dir.x);
                 float horizDot = Math.Abs(_weightDirs[i].Dot(rotatedDir));
 
-                // this is a smaller weight so they are more likely to
+                // this is a smaller weight so they are more likely to pick the
-                // pick the direction they are currently heading when
+                // direction they are currently heading when choosing between two
-                // choosing between two horizontal weights
+                // horizontal weights
                 float currDirDot = (_weightDirs[i].Dot(Direction) + 1) / 16;
 
                 // square so lower values are even lower
@@ -158,7 +170,7 @@ namespace SupaLidlGame.Characters
                             else
                             {
                                 float dot = _weightDirs[i].Dot(_weightDirs[j]);
-                                _weights[j] -= (dot + 1) / 4;
+                                _weights[j] -= (dot + 1) / 2;
                             }
                         }
                     }

Characters/Player.cs

@@ -9,10 +9,5 @@ namespace SupaLidlGame.Characters
         {
 
         }
-
-		public override void _Process(double delta)
-		{
-			Direction = Input.GetVector("ui_left", "ui_right", "ui_up", "ui_down");
-		}
     }
 }

Characters/Player.tscn

@@ -1,13 +1,21 @@
-[gd_scene load_steps=4 format=3 uid="uid://bncaar8vp3b84"]
+[gd_scene load_steps=9 format=3 uid="uid://bncaar8vp3b84"]
 
 [ext_resource type="Script" path="res://Characters/Player.cs" id="1_flygr"]
 [ext_resource type="Texture2D" uid="uid://bw052v8ikfget" path="res://icon.svg" id="2_xmgd1"]
+[ext_resource type="Script" path="res://Characters/States/Machine.cs" id="3_npkjp"]
+[ext_resource type="Script" path="res://Characters/States/PlayerIdleState.cs" id="4_4k4mb"]
+[ext_resource type="Script" path="res://Characters/States/PlayerMoveState.cs" id="5_tx5rw"]
+[ext_resource type="Script" path="res://Characters/States/PlayerRollState.cs" id="6_6bgrj"]
 
 [sub_resource type="RectangleShape2D" id="RectangleShape2D_bfqew"]
 size = Vector2(32, 16)
 
-[node name="Node2D" type="CharacterBody2D"]
+[sub_resource type="LabelSettings" id="LabelSettings_q5h1n"]
+font_size = 24
+
+[node name="Player" type="CharacterBody2D" node_paths=PackedStringArray("StateMachine")]
 script = ExtResource("1_flygr")
+StateMachine = NodePath("StateMachine")
 
 [node name="Sprite2D" type="Sprite2D" parent="."]
 scale = Vector2(0.25, 0.25)
@@ -21,4 +29,36 @@ shape = SubResource("RectangleShape2D_bfqew")
 current = true
 zoom = Vector2(4, 4)
 
-[node name="StateManager" type="Node" parent="."]
+[node name="StateMachine" type="Node" parent="." node_paths=PackedStringArray("InitialState", "Character")]
+script = ExtResource("3_npkjp")
+InitialState = NodePath("Idle")
+Character = NodePath("..")
+DebugLevel = 2
+
+[node name="Idle" type="Node" parent="StateMachine" node_paths=PackedStringArray("MoveState")]
+script = ExtResource("4_4k4mb")
+MoveState = NodePath("../Move")
+
+[node name="Move" type="Node" parent="StateMachine" node_paths=PackedStringArray("IdleState", "RollState")]
+script = ExtResource("5_tx5rw")
+IdleState = NodePath("../Idle")
+RollState = NodePath("../Roll")
+
+[node name="Roll" type="Node" parent="StateMachine" node_paths=PackedStringArray("IdleState")]
+script = ExtResource("6_6bgrj")
+IdleState = NodePath("../Idle")
+
+[node name="Debug" type="Control" parent="."]
+layout_mode = 3
+anchors_preset = 0
+
+[node name="State" type="Label" parent="Debug"]
+offset_left = -20.0
+offset_top = -60.0
+offset_right = 20.0
+offset_bottom = -34.0
+text = "lol"
+label_settings = SubResource("LabelSettings_q5h1n")
+horizontal_alignment = 1
+
+[node name="Node" type="Node" parent="."]

Characters/States/CharacterState.cs

@@ -0,0 +1,36 @@
+using Godot;
+
+namespace SupaLidlGame.Characters.State
+{
+    public partial class CharacterState : Node
+    {
+        public Character Character { get; set; }
+
+        /// <summary>
+        /// Called when the <c>Character</c> enters this <c>CharacterState</c>.
+        /// </summary>
+        /// <remarks>
+        /// This returns a <c>CharacterState</c> in case a state is being
+        /// transitioned to but wants to transition to another state. For
+        /// example, an attack state can return to an idle state, but that idle
+        /// state can override it to the move state immediately when necessary.
+        /// </remarks>
+        public virtual CharacterState Enter(CharacterState previousState) => null;
+
+        /// <summary>
+        /// Called when the <c>Character</c> exits this <c>CharacterState</c>.
+        /// </summary>
+        public virtual void Exit(CharacterState nextState) { }
+
+        public virtual CharacterState Process(double delta) => null;
+
+        public virtual CharacterState PhysicsProcess(double delta)
+        {
+            Character.Velocity = Character.Direction * Character.Speed;
+            Character.MoveAndSlide();
+            return null;
+        }
+
+        public virtual CharacterState Input(InputEvent @event) => null;
+    }
+}

Characters/States/Machine.cs

@@ -0,0 +1,87 @@
+using Godot;
+
+namespace SupaLidlGame.Characters.State
+{
+    public partial class Machine : Node
+    {
+        protected Character _character;
+
+        public CharacterState State { get; protected set; }
+
+        [Export]
+        public CharacterState InitialState { get; set; }
+
+        [Export]
+        public Character Character { get; set; }
+
+        [Export]
+        public int DebugLevel { get; set; }
+
+        public override void _Ready()
+        {
+            ChangeState(InitialState);
+        }
+
+        public void ChangeState(CharacterState nextState, bool isProxied = false)
+        {
+            if (DebugLevel >= 2)
+            {
+                if (State is not null)
+                {
+                    string proxyNote = isProxied ? " (proxied)" : "";
+                    GD.Print($"Transition{proxyNote} {State.Name} -> {nextState.Name}");
+                }
+            }
+
+            if (DebugLevel >= 1)
+            {
+                if (GetNode<Label>("../Debug/State") is Label label)
+                {
+                    label.Text = nextState.Name;
+                }
+            }
+
+            nextState.Character = Character;
+            if (State != null)
+            {
+                State.Exit(nextState);
+            }
+
+            var nextNextState = nextState.Enter(State);
+
+            State = nextState;
+
+            if (nextNextState is not null)
+            {
+                ChangeState(nextNextState, true);
+            }
+        }
+
+        public void Process(double delta)
+        {
+            CharacterState nextState = State.Process(delta);
+            if (nextState is not null)
+            {
+                ChangeState(nextState);
+            }
+        }
+
+        public void PhysicsProcess(double delta)
+        {
+            CharacterState nextState = State.PhysicsProcess(delta);
+            if (nextState is not null)
+            {
+                ChangeState(nextState);
+            }
+        }
+
+        public void Input(InputEvent @event)
+        {
+            CharacterState nextState = State.Input(@event);
+            if (nextState is not null)
+            {
+                ChangeState(nextState);
+            }
+        }
+    }
+}

Characters/States/MoveState.cs

@@ -0,0 +1,10 @@
+namespace SupaLidlGame.Characters.State
+{
+    public partial class MoveState : CharacterState
+    {
+        public override CharacterState PhysicsProcess(double delta)
+        {
+            return base.PhysicsProcess(delta);
+        }
+    }
+}

Characters/States/NPCIdleState.cs

@@ -0,0 +1,20 @@
+using Godot;
+
+namespace SupaLidlGame.Characters.State
+{
+    public partial class NPCIdleState : NPCState
+    {
+        [Export]
+        public CharacterState MoveState { get; set; }
+
+        public override CharacterState Process(double delta)
+        {
+            base.Process(delta);
+            if (Character.Direction.LengthSquared() > 0)
+            {
+                return MoveState;
+            }
+            return null;
+        }
+    }
+}

Characters/States/NPCMoveState.cs

@@ -0,0 +1,20 @@
+using Godot;
+
+namespace SupaLidlGame.Characters.State
+{
+    public partial class NPCMoveState : NPCState
+    {
+        [Export]
+        public CharacterState IdleState { get; set; }
+
+        public override CharacterState Process(double delta)
+        {
+            base.Process(delta);
+            if (Character.Direction.LengthSquared() == 0)
+            {
+                return IdleState;
+            }
+            return null;
+        }
+    }
+}

Characters/States/NPCState.cs

@@ -0,0 +1,13 @@
+namespace SupaLidlGame.Characters.State
+{
+    public partial class NPCState : CharacterState
+    {
+        protected NPC _npc => Character as NPC;
+
+        public override CharacterState Process(double delta)
+        {
+            _npc.ThinkProcess(delta);
+            return base.Process(delta);
+        }
+    }
+}

Characters/States/PlayerAttackState.cs

@@ -0,0 +1,41 @@
+using Godot;
+using Godot.Collections;
+using Godot.NativeInterop;
+
+namespace SupaLidlGame.Characters.State
+{
+    public partial class PlayerAttackState : PlayerState
+    {
+        [Export]
+        public CharacterState IdleState { get; set; }
+
+        private float _attackTime = 0;
+
+        public override CharacterState Enter(CharacterState previousState)
+        {
+            _attackTime = 0;
+            return base.Enter(previousState);
+        }
+
+        public override void Exit(CharacterState nextState)
+        {
+            _attackTime = 0;
+            base.Exit(nextState);
+        }
+
+        public override CharacterState Input(InputEvent @event)
+        {
+            return base.Input(@event);
+        }
+
+        public override CharacterState PhysicsProcess(double delta)
+        {
+            return base.PhysicsProcess(delta);
+        }
+
+        public override CharacterState Process(double delta)
+        {
+            return base.Process(delta);
+        }
+    }
+}

Characters/States/PlayerIdleState.cs

@@ -0,0 +1,37 @@
+using Godot;
+
+namespace SupaLidlGame.Characters.State
+{
+    public partial class PlayerIdleState : PlayerState
+    {
+        [Export]
+        public CharacterState MoveState { get; set; }
+
+        public override CharacterState Enter(CharacterState previousState)
+        {
+            GD.Print("Entered idle state");
+            if (previousState is not PlayerMoveState)
+            {
+                if (Character.Direction.LengthSquared() > 0)
+                {
+                    // other states like attacking or rolling can just delegate
+                    // the work of checking if the player is moving to this idle
+                    // state, so they do not have to manually check if the player
+                    // wants to move to switch to the move state.
+                    return MoveState;
+                }
+            }
+            return base.Enter(previousState);
+        }
+
+        public override CharacterState Process(double delta)
+        {
+            base.Process(delta);
+            if (Character.Direction.LengthSquared() > 0)
+            {
+                return MoveState;
+            }
+            return null;
+        }
+    }
+}

Characters/States/PlayerMoveState.cs

@@ -0,0 +1,39 @@
+using Godot;
+
+namespace SupaLidlGame.Characters.State
+{
+    public partial class PlayerMoveState : PlayerState
+    {
+        [Export]
+        public CharacterState IdleState { get; set; }
+
+        [Export]
+        public CharacterState RollState { get; set; }
+
+        public override CharacterState Enter(CharacterState previousState)
+        {
+            Godot.GD.Print("Started moving");
+            return base.Enter(previousState);
+        }
+
+        public override CharacterState Process(double delta)
+        {
+            base.Process(delta);
+            if (Character.Direction.LengthSquared() == 0)
+            {
+                return IdleState;
+            }
+            return null;
+        }
+
+        public override CharacterState Input(Godot.InputEvent @event)
+        {
+            if (@event.IsActionPressed("roll"))
+            {
+                return RollState;
+            }
+
+            return null;
+        }
+    }
+}

Characters/States/PlayerRollState.cs

@@ -0,0 +1,48 @@
+using Godot;
+
+namespace SupaLidlGame.Characters.State
+{
+    public partial class PlayerRollState : PlayerState
+    {
+        [Export]
+        public CharacterState IdleState { get; set; }
+
+        private double _timeLeftToRoll = 0;
+
+        private Vector2 _rollDirection = Vector2.Zero;
+
+        public override CharacterState Enter(CharacterState previousState)
+        {
+            _timeLeftToRoll = 0.5;
+            // roll the direction we were previously moving in
+            _rollDirection = Character.Direction;
+            return base.Enter(previousState);
+        }
+
+        public override void Exit(CharacterState nextState)
+        {
+            // we want to reset our state variables in case we are forced out of
+            // this state (e.g. from death)
+            _timeLeftToRoll = 0;
+            _rollDirection = Character.Direction;
+            base.Exit(nextState);
+        }
+
+        public override CharacterState Process(double delta)
+        {
+            Character.Direction = _rollDirection;
+            if ((_timeLeftToRoll -= delta) <= 0)
+            {
+                return IdleState;
+            }
+            return null;
+        }
+
+        public override CharacterState PhysicsProcess(double delta)
+        {
+            Character.Velocity = Character.Direction * Character.Speed * 1.5f;
+            Character.MoveAndSlide();
+            return null;
+        }
+    }
+}

Characters/States/PlayerState.cs

@@ -0,0 +1,15 @@
+namespace SupaLidlGame.Characters.State
+{
+    public partial class PlayerState : CharacterState
+    {
+        //public PlayerMachine PlayerMachine => Machine as PlayerMachine;
+        protected Player _player => Character as Player;
+
+        public override CharacterState Process(double delta)
+        {
+            Character.Direction = Godot.Input.GetVector("ui_left", "ui_right",
+                                                        "ui_up", "ui_down");
+            return base.Process(delta);
+        }
+    }
+}

project.godot

@@ -45,6 +45,11 @@ ui_down={
 , Object(InputEventJoypadButton,"resource_local_to_scene":false,"resource_name":"","device":0,"button_index":12,"pressure":0.0,"pressed":false,"script":null)
 ]
 }
+roll={
+"deadzone": 0.5,
+"events": [Object(InputEventMouseButton,"resource_local_to_scene":false,"resource_name":"","device":-1,"window_id":0,"alt_pressed":false,"shift_pressed":false,"ctrl_pressed":false,"meta_pressed":false,"button_mask":0,"position":Vector2(0, 0),"global_position":Vector2(0, 0),"factor":1.0,"button_index":3,"pressed":false,"double_click":false,"script":null)
+]
+}
 
 [physics]