Multiplayer

components/enemy/enemy.gd

@@ -69,7 +69,7 @@ func _on_gravity_changed(new_gravity):
 
 
 func _on_hitbox_body_entered(body):
-	if body.name == "Player":
+	if body.is_in_group("players"):
 		if squashable and body.velocity.y > 0 and body.position.y < position.y:
 			body.stomp()
 			queue_free()

components/platform/platform.gd

@@ -83,7 +83,7 @@ func _ready():
 
 
 func _on_area_2d_body_entered(body):
-	if not body.name == "Player":
+	if not body.is_in_group("players"):
 		return
 	if fall_time > 0:
 		fall_timer.start(fall_time)

components/player/player.tscn

@@ -7,7 +7,7 @@
 radius = 31.0
 height = 92.0
 
-[node name="Player" type="CharacterBody2D"]
+[node name="Player" type="CharacterBody2D" groups=["players"]]
 collision_layer = 3
 collision_mask = 5
 floor_constant_speed = true

doc/MODS.md

@@ -135,6 +135,15 @@ on one of these nodes. In the Inspector, you can adjust their behaviour:
 These platforms can be made into moving platforms by using Godot's Animation
 functionality.
 
+### Multiplayer and player controls
+
+Click on the `Player` node. In the inspector, try changing the Player
+dropdown to "Two" or "Both".
+
+Duplicate the `Player` node. Move it next to the existing player. Then
+change the Player to "Two" in the duplicated one. Now the game is
+multiplayer.
+
 ### Player and flag appearance
 
 Click on the `Player` node. In the inspector, observe where it says `Sprite

hud.tscn

@@ -14,15 +14,19 @@ anchor_left = 0.5
 anchor_top = 0.5
 anchor_right = 0.5
 anchor_bottom = 0.5
-offset_left = -194.5
-offset_top = -396.0
-offset_right = 194.5
-offset_bottom = -217.0
+offset_left = -367.5
+offset_top = -487.0
+offset_right = 367.5
+offset_bottom = 56.0
 grow_horizontal = 2
 grow_vertical = 2
 size_flags_horizontal = 4
 theme_override_font_sizes/font_size = 64
-text = "Press any key
+text = "Controls
+Player One: Arrow Keys
+Player Two: WASD
+
+Press any key
 to Start"
 horizontal_alignment = 1
 

project.godot

@@ -28,6 +28,69 @@ window/size/window_width_override=960
 window/size/window_height_override=540
 window/stretch/mode="canvas_items"
 
+[global_group]
+
+players=""
+
+[input]
+
+player_2_up={
+"deadzone": 0.5,
+"events": [Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":-1,"window_id":0,"alt_pressed":false,"shift_pressed":false,"ctrl_pressed":false,"meta_pressed":false,"pressed":false,"keycode":87,"physical_keycode":0,"key_label":0,"unicode":119,"location":0,"echo":false,"script":null)
+, Object(InputEventJoypadButton,"resource_local_to_scene":false,"resource_name":"","device":1,"button_index":11,"pressure":0.0,"pressed":false,"script":null)
+, Object(InputEventJoypadMotion,"resource_local_to_scene":false,"resource_name":"","device":1,"axis":1,"axis_value":-1.0,"script":null)
+]
+}
+player_2_down={
+"deadzone": 0.5,
+"events": [Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":-1,"window_id":0,"alt_pressed":false,"shift_pressed":false,"ctrl_pressed":false,"meta_pressed":false,"pressed":false,"keycode":83,"physical_keycode":0,"key_label":0,"unicode":115,"location":0,"echo":false,"script":null)
+, Object(InputEventJoypadButton,"resource_local_to_scene":false,"resource_name":"","device":1,"button_index":12,"pressure":0.0,"pressed":false,"script":null)
+, Object(InputEventJoypadMotion,"resource_local_to_scene":false,"resource_name":"","device":1,"axis":1,"axis_value":1.0,"script":null)
+]
+}
+player_2_left={
+"deadzone": 0.5,
+"events": [Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":-1,"window_id":0,"alt_pressed":false,"shift_pressed":false,"ctrl_pressed":false,"meta_pressed":false,"pressed":false,"keycode":65,"physical_keycode":0,"key_label":0,"unicode":97,"location":0,"echo":false,"script":null)
+, Object(InputEventJoypadButton,"resource_local_to_scene":false,"resource_name":"","device":1,"button_index":13,"pressure":0.0,"pressed":false,"script":null)
+, Object(InputEventJoypadMotion,"resource_local_to_scene":false,"resource_name":"","device":1,"axis":0,"axis_value":-1.0,"script":null)
+]
+}
+player_2_right={
+"deadzone": 0.5,
+"events": [Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":-1,"window_id":0,"alt_pressed":false,"shift_pressed":false,"ctrl_pressed":false,"meta_pressed":false,"pressed":false,"keycode":68,"physical_keycode":0,"key_label":0,"unicode":100,"location":0,"echo":false,"script":null)
+, Object(InputEventJoypadButton,"resource_local_to_scene":false,"resource_name":"","device":1,"button_index":14,"pressure":0.0,"pressed":false,"script":null)
+, Object(InputEventJoypadMotion,"resource_local_to_scene":false,"resource_name":"","device":1,"axis":2,"axis_value":1.0,"script":null)
+]
+}
+player_1_up={
+"deadzone": 0.5,
+"events": [Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":-1,"window_id":0,"alt_pressed":false,"shift_pressed":false,"ctrl_pressed":false,"meta_pressed":false,"pressed":false,"keycode":4194320,"physical_keycode":0,"key_label":0,"unicode":0,"location":0,"echo":false,"script":null)
+, Object(InputEventJoypadButton,"resource_local_to_scene":false,"resource_name":"","device":0,"button_index":11,"pressure":0.0,"pressed":false,"script":null)
+, Object(InputEventJoypadMotion,"resource_local_to_scene":false,"resource_name":"","device":0,"axis":1,"axis_value":-1.0,"script":null)
+]
+}
+player_1_down={
+"deadzone": 0.5,
+"events": [Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":-1,"window_id":0,"alt_pressed":false,"shift_pressed":false,"ctrl_pressed":false,"meta_pressed":false,"pressed":false,"keycode":4194322,"physical_keycode":0,"key_label":0,"unicode":0,"location":0,"echo":false,"script":null)
+, Object(InputEventJoypadButton,"resource_local_to_scene":false,"resource_name":"","device":0,"button_index":12,"pressure":0.0,"pressed":false,"script":null)
+, Object(InputEventJoypadMotion,"resource_local_to_scene":false,"resource_name":"","device":0,"axis":1,"axis_value":1.0,"script":null)
+]
+}
+player_1_left={
+"deadzone": 0.5,
+"events": [null, Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":0,"window_id":0,"alt_pressed":false,"shift_pressed":false,"ctrl_pressed":false,"meta_pressed":false,"pressed":false,"keycode":4194319,"physical_keycode":0,"key_label":0,"unicode":0,"location":0,"echo":false,"script":null)
+, Object(InputEventJoypadButton,"resource_local_to_scene":false,"resource_name":"","device":0,"button_index":13,"pressure":0.0,"pressed":false,"script":null)
+, Object(InputEventJoypadMotion,"resource_local_to_scene":false,"resource_name":"","device":0,"axis":0,"axis_value":-1.0,"script":null)
+]
+}
+player_1_right={
+"deadzone": 0.5,
+"events": [Object(InputEventKey,"resource_local_to_scene":false,"resource_name":"","device":-1,"window_id":0,"alt_pressed":false,"shift_pressed":false,"ctrl_pressed":false,"meta_pressed":false,"pressed":false,"keycode":4194321,"physical_keycode":0,"key_label":0,"unicode":0,"location":0,"echo":false,"script":null)
+, Object(InputEventJoypadButton,"resource_local_to_scene":false,"resource_name":"","device":0,"button_index":14,"pressure":0.0,"pressed":false,"script":null)
+, Object(InputEventJoypadMotion,"resource_local_to_scene":false,"resource_name":"","device":0,"axis":0,"axis_value":1.0,"script":null)
+]
+}
+
 [layer_names]
 
 2d_physics/layer_1="Player"

scripts/global.gd

@@ -9,6 +9,7 @@ signal gravity_changed(gravity: float)
 signal timer_added
 
 enum Endings { WIN, LOSE }
+enum Player { ONE, TWO, BOTH }
 
 ## Timer for finishing the level.
 var timer: Timer

scripts/player.gd

@@ -3,6 +3,24 @@ class_name Player
 extends CharacterBody2D
 ## A player's character, which can walk, jump, and stomp on enemies.
 
+const _PLAYER_ACTIONS = {
+	Global.Player.ONE:
+	{
+		"jump": "player_1_up",
+		"left": "player_1_left",
+		"right": "player_1_right",
+	},
+	Global.Player.TWO:
+	{
+		"jump": "player_2_up",
+		"left": "player_2_left",
+		"right": "player_2_right",
+	},
+}
+
+## Which player controls this character?
+@export var player: Global.Player = Global.Player.ONE
+
 ## Use this to change the sprite frames of your character.
 @export var sprite_frames: SpriteFrames = _initial_sprite_frames:
 	set = _set_sprite_frames
@@ -104,6 +122,43 @@ func stomp():
 	_jump()
 
 
+func _player_just_pressed(action):
+	if player == Global.Player.BOTH:
+		return (
+			Input.is_action_just_pressed(_PLAYER_ACTIONS[Global.Player.ONE][action])
+			or Input.is_action_just_pressed(_PLAYER_ACTIONS[Global.Player.TWO][action])
+		)
+	return Input.is_action_just_pressed(_PLAYER_ACTIONS[player][action])
+
+
+func _player_just_released(action):
+	if player == Global.Player.BOTH:
+		return (
+			Input.is_action_just_released(_PLAYER_ACTIONS[Global.Player.ONE][action])
+			or Input.is_action_just_released(_PLAYER_ACTIONS[Global.Player.TWO][action])
+		)
+	return Input.is_action_just_released(_PLAYER_ACTIONS[player][action])
+
+
+func _get_player_axis(action_a, action_b):
+	if player == Global.Player.BOTH:
+		return clamp(
+			(
+				Input.get_axis(
+					_PLAYER_ACTIONS[Global.Player.ONE][action_a],
+					_PLAYER_ACTIONS[Global.Player.ONE][action_b]
+				)
+				+ Input.get_axis(
+					_PLAYER_ACTIONS[Global.Player.TWO][action_a],
+					_PLAYER_ACTIONS[Global.Player.TWO][action_b]
+				)
+			),
+			-1,
+			1
+		)
+	return Input.get_axis(_PLAYER_ACTIONS[player][action_a], _PLAYER_ACTIONS[player][action_b])
+
+
 func _physics_process(delta):
 	# Don't move if there are no lives left.
 	if Global.lives <= 0:
@@ -114,15 +169,15 @@ func _physics_process(delta):
 		coyote_timer = (coyote_time + delta)
 		double_jump_armed = false
 
-	if Input.is_action_just_pressed("ui_accept"):
+	if _player_just_pressed("jump"):
 		jump_buffer_timer = (jump_buffer + delta)
 
 	if jump_buffer_timer > 0 and (double_jump_armed or coyote_timer > 0):
 		_jump()
 
 	# Reduce velocity if the player lets go of the jump key before the apex.
 	# This allows controlling the height of the jump.
-	if Input.is_action_just_released("ui_accept") and velocity.y < 0:
+	if _player_just_released("jump") and velocity.y < 0:
 		velocity.y *= (1 - (jump_cut_factor / 100.00))
 
 	# Add the gravity.
@@ -131,7 +186,7 @@ func _physics_process(delta):
 
 	# Get the input direction and handle the movement/deceleration.
 	# As good practice, you should replace UI actions with custom gameplay actions.
-	var direction = Input.get_axis("ui_left", "ui_right")
+	var direction = _get_player_axis("left", "right")
 	if direction:
 		velocity.x = move_toward(
 			velocity.x,