Merge pull request #6 from endlessm/player-physics-improvements

Player physics improvements

components/enemy/enemy.gd

@@ -71,7 +71,7 @@ func _on_gravity_changed(new_gravity):
 func _on_hitbox_body_entered(body):
 	if body.name == "Player":
 		if squashable and body.velocity.y > 0 and body.position.y < position.y:
-			body.velocity.y = body.jump_velocity
+			body.stomp()
 			queue_free()
 		elif player_loses_life:
 			Global.lives -= 1

components/player/player.tscn

@@ -14,6 +14,21 @@ floor_constant_speed = true
 floor_snap_length = 32.0
 script = ExtResource("1_w3ms2")
 
+[node name="DoubleJumpParticles" type="CPUParticles2D" parent="."]
+unique_name_in_owner = true
+emitting = false
+amount = 60
+lifetime = 0.2
+one_shot = true
+explosiveness = 0.54
+randomness = 0.25
+emission_shape = 1
+emission_sphere_radius = 36.72
+particle_flag_align_y = true
+gravity = Vector2(0, 1)
+scale_amount_max = 5.0
+color = Color(1, 1, 0, 1)
+
 [node name="AnimatedSprite2D" type="AnimatedSprite2D" parent="."]
 unique_name_in_owner = true
 position = Vector2(0, -64)

scripts/player.gd

@@ -9,16 +9,47 @@ extends CharacterBody2D
 @export_range(0, 1000, 10, "suffix:px/s") var speed: float = 500.0:
 	set = _set_speed
 
+## How fast does your character accelerate?
+@export_range(0, 5000, 1000, "suffix:px/s²") var acceleration: float = 5000.0
+
 ## How high does your character jump? Note that the gravity will
 ## be influenced by the [member GameLogic.gravity].
 @export_range(-1000, 1000, 10, "suffix:px/s") var jump_velocity = -880.0
 
+## How much should the character's jump be reduced if you let go of the jump
+## key before the top of the jump? [code]0[/code] means “not at all”;
+## [code]100[/code] means “upwards movement completely stops”.
+@export_range(0, 100, 5, "suffix:%") var jump_cut_factor: float = 20
+
+## How long after the character walks off a ledge can they still jump?
+## This is often set to a small positive number to allow the player a little
+## margin for error before they start falling.
+@export_range(0, 0.5, 1 / 60.0, "suffix:s") var coyote_time: float = 5.0 / 60.0
+
+## If the character is about to land on the floor, how early can the player
+## the jump key to jump as soon as the character lands? This is often set to
+## a small positive number to allow the player a little margin for error.
+@export_range(0, 0.5, 1 / 60.0, "suffix:s") var jump_buffer: float = 5.0 / 60.0
+
+## Can your character jump a second time while still in the air?
+@export var double_jump: bool = false
+
+# If positive, the player is either on the ground, or left the ground less than this long ago
+var coyote_timer: float = 0
+
+# If positive, the player pressed jump this long ago
+var jump_buffer_timer: float = 0
+
+# If true, the player is already jumping and can perform a double-jump
+var double_jump_armed: bool = false
+
 # Get the gravity from the project settings to be synced with RigidBody nodes.
 var gravity = ProjectSettings.get_setting("physics/2d/default_gravity")
 var original_position: Vector2
 
 @onready var _sprite: AnimatedSprite2D = %AnimatedSprite2D
 @onready var _initial_sprite_frames: SpriteFrames = %AnimatedSprite2D.sprite_frames
+@onready var _double_jump_particles: CPUParticles2D = %DoubleJumpParticles
 
 
 func _set_sprite_frames(new_sprite_frames):
@@ -55,26 +86,58 @@ func _on_gravity_changed(new_gravity):
 	gravity = new_gravity
 
 
+func _jump():
+	velocity.y = jump_velocity
+	coyote_timer = 0
+	jump_buffer_timer = 0
+	if double_jump_armed:
+		double_jump_armed = false
+		_double_jump_particles.emitting = true
+	elif double_jump:
+		double_jump_armed = true
+
+
+func stomp():
+	double_jump_armed = false
+	_jump()
+
+
 func _physics_process(delta):
 	# Don't move if there are no lives left.
 	if Global.lives <= 0:
 		return
 
+	# Handle jump
+	if is_on_floor():
+		coyote_timer = (coyote_time + delta)
+		double_jump_armed = false
+
+	if Input.is_action_just_pressed("ui_accept"):
+		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:
+		velocity.y *= (1 - (jump_cut_factor / 100.00))
+
 	# Add the gravity.
-	if not is_on_floor():
+	if coyote_timer <= 0:
 		velocity.y += gravity * delta
 
-	# Handle jump.
-	if Input.is_action_just_pressed("ui_accept") and is_on_floor():
-		velocity.y = jump_velocity
-
 	# 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")
 	if direction:
-		velocity.x = direction * speed
+		velocity.x = move_toward(
+			velocity.x,
+			sign(direction) * speed,
+			abs(direction) * acceleration * delta,
+		)
 	else:
-		velocity.x = move_toward(velocity.x, 0, speed)
+		velocity.x = move_toward(velocity.x, 0, acceleration * delta)
 
 	if velocity == Vector2.ZERO:
 		_sprite.play("idle")
@@ -90,10 +153,15 @@ func _physics_process(delta):
 
 	move_and_slide()
 
+	coyote_timer -= delta
+	jump_buffer_timer -= delta
+
 
 func reset():
 	position = original_position
 	velocity = Vector2.ZERO
+	coyote_timer = 0
+	jump_buffer_timer = 0
 
 
 func _on_lives_changed():