Add a savegame system using slots and a main menu, allow player to move RigidBody2Ds using apply_impulse(), increased physics tick, enabled FXAA, and more.

core/globals/gamestate.gd

@@ -0,0 +1,87 @@
+extends Node
+
+# gamestate
+
+var last_entrypoint: String
+
+func reset_gamestate():
+	# defaults
+	last_entrypoint = "intro_start"
+
+# save/load slot
+
+const slot_min: int = 0
+const slot_max: int = 3
+
+var current_slot: int = -1
+var current_slot_locked: bool = false
+
+func _check_slot_idx(idx: int) -> bool:
+	# returns if slot index is valid (in bounds)
+	if idx < slot_min or idx > slot_max:
+		push_error("Slot index %s is invalid." % current_slot)
+		return false
+	return true
+
+func save_slot():
+	# flush game state to slot
+	if _check_slot_idx(current_slot):
+		var slot_path: String = "user://slot%s.save" % current_slot
+		var f = FileAccess.open(slot_path, FileAccess.WRITE)
+		if f == null:
+			push_error("Couldn't open %s" % slot_path)
+			quit(1)
+			return
+		# create serializable data structure
+		var data: Dictionary = {
+			"last_entrypoint": last_entrypoint
+		}
+		var data_serialized = JSON.stringify(data)
+		if data_serialized == null:
+			push_error("Couldn't serialize save data for slot %s" % current_slot)
+			quit(1)
+			return
+		f.store_string(data_serialized)
+
+func load_slot():
+	# load gamestate from slot
+	if _check_slot_idx(current_slot):
+		reset_gamestate() # init gamestate with defaults
+		var slot_path: String = "user://slot%s.save" % current_slot
+		if FileAccess.file_exists(slot_path):
+			var f = FileAccess.open(slot_path, FileAccess.READ)
+			if f == null:
+				push_error("Couldn't open %s" % slot_path)
+				quit(1)
+				return
+			var data_serialized = f.get_as_text()
+			var data = JSON.parse_string(data_serialized)
+			if data == null:
+				push_error("Couldn't deserialize slot %s" % slot_path)
+				quit(1)
+				return
+			# read values
+			last_entrypoint = data["last_entrypoint"]
+		else:
+			save_slot() # new game; save defaults
+
+func reset_slot(idx: int):
+	# reset a save slot
+	if _check_slot_idx(idx):
+		if current_slot == idx:
+			reset_gamestate()
+		# delete slot file
+		var slot_path: String = "user://slot%s.save" % idx
+		if FileAccess.file_exists(slot_path):
+			DirAccess.remove_absolute(slot_path)
+
+#
+
+func quit(code: int):
+	# defer get_tree().quit() to not lose the last error/stdout
+	# see https://github.com/godotengine/godot/issues/90667
+	await get_tree().create_timer(0.1).timeout
+	get_tree().quit(code)
+
+func _ready() -> void:
+	reset_gamestate()

core/globals/levels.gd

@@ -1,59 +1,79 @@
 extends Node
 
+const mainmenu_player_pos: Vector2 = Vector2(0, 128 + 32)
+
 class Entrypoint extends Object:
 	var scene_name: String
 	var player_position: Vector2
-	var reset_physics: bool
+	var initial_velocity: Vector2
 	func _init(
 		scene_name_: String,
 		player_position_: Vector2,
-		reset_physics_: bool
+		initial_velocity_: Vector2 = Vector2.ZERO
 	) -> void:
 		self.scene_name = scene_name_
 		self.player_position = player_position_
-		self.reset_physics = reset_physics_
+		self.initial_velocity = initial_velocity_
 
 const SCENES = {
-	"intro": "uid://c6w7lrydi43ts"
+	"intro": "uid://c6w7lrydi43ts",
+	"test": "uid://dqf665b540tfg",
 }
 
 var ENTRYPOINTS = {
-	"intro_start": Entrypoint.new("intro", Vector2(0, 0), true)
+	"intro_start": Entrypoint.new("intro", Vector2.ZERO),
+	"test": Entrypoint.new("test", Vector2.ZERO),
 }
 
+var MENU_SCENE: PackedScene = preload("res://menu/menu.tscn")
+
 # load that stuff
 
-var level_root: Node
-var player: Node2D
+func _pre_load_checks() -> bool:
+	if NodeRegistry.level_root_container == null:
+		push_error("Can't load level, level_root is not registered yet.")
+		return false
+	if NodeRegistry.player == null:
+		push_error("Can't load entrypoint, player is not registered yet.")
+		return false
+	return true
 
 func load_scene(scn_name: String) -> bool:  # returns true on success
-	if level_root == null:
-		push_error("Can't load level, level_root is not registered yet.")
+	if not _pre_load_checks():
 		return false
 	if not scn_name in SCENES:
 		push_error("Level " + scn_name + " doesn't exist.")
 		return false
 	unload_scene()
 	var scn = load(SCENES[scn_name])
-	level_root.add_child(scn.instantiate())
+	NodeRegistry.level_root_container.add_child(scn.instantiate())
 	return true
 
 func unload_scene():
-	for c in level_root.get_children():
-		c.queue_free()
+	if NodeRegistry.level_root_container != null:
+		for c in NodeRegistry.level_root_container.get_children():
+			c.queue_free()
 
 func load_entrypoint(ep_name: String) -> bool: # returns true on success
 	if not ep_name in ENTRYPOINTS:
 		push_error("Entrypoint " + ep_name + " doesn't exist.")
 		return false
-	if player == null:
-		push_error("Can't load entrypoint, player is not registered yet.")
+	if not _pre_load_checks():
 		return false
 	var e: Entrypoint = ENTRYPOINTS[ep_name]
 	if load_scene(e.scene_name):
-		player.position = e.player_position
-		if e.reset_physics:
-			player.reset_physics()
+		NodeRegistry.player.position = e.player_position
+		NodeRegistry.player.velocity = e.initial_velocity
+		Gamestate.last_entrypoint = ep_name
+		Gamestate.save_slot() # save game
 		return true
 	else:
 		return false
+
+func load_menu():
+	if not _pre_load_checks():
+		return false
+	unload_scene()
+	NodeRegistry.level_root_container.add_child(MENU_SCENE.instantiate())
+	NodeRegistry.player.position = mainmenu_player_pos
+	return true

core/globals/node_registry.gd

@@ -0,0 +1,4 @@
+extends Node
+
+var player: CharacterBody2D
+var level_root_container: Node

levels/intro.gd

@@ -1,5 +1,9 @@
 extends Node2D
 
 func _on_area_2d_body_entered(body: Node2D) -> void:
-	if body == Levels.player:
-		Levels.load_entrypoint("intro_start")
+	if body == NodeRegistry.player:
+		NodeRegistry.player.die()
+
+func _on_next_level_body_entered(body: Node2D) -> void:
+	if body == NodeRegistry.player:
+		Levels.load_entrypoint("test")

levels/intro.tscn

@@ -24,4 +24,11 @@ color = Color(1, 0.1, 0, 1)
 polygon = PackedVector2Array(256, 384, 360, 384, 360, 440, 256, 440)
 color = Color(1, 0.1, 0, 1)
 
+[node name="next_level" type="Area2D" parent="."]
+
+[node name="Polygon" parent="next_level" instance=ExtResource("1_cup10")]
+polygon = PackedVector2Array(416, 400, 416, 424, 440, 424, 440, 400)
+color = Color(0.484431, 0.687354, 1, 1)
+
 [connection signal="body_entered" from="Area2D" to="." method="_on_area_2d_body_entered"]
+[connection signal="body_entered" from="next_level" to="." method="_on_next_level_body_entered"]

levels/test.tscn

@@ -0,0 +1,10 @@
+[gd_scene load_steps=2 format=3 uid="uid://dqf665b540tfg"]
+
+[ext_resource type="PackedScene" uid="uid://cbynoofsjcl45" path="res://core/polygon.tscn" id="1_xm2ft"]
+
+[node name="Test" type="Node2D"]
+
+[node name="StaticBody2D" type="StaticBody2D" parent="."]
+
+[node name="Polygon" parent="StaticBody2D" instance=ExtResource("1_xm2ft")]
+polygon = PackedVector2Array(-104, 232, -104, 320, 552, 320, 552, 232)

main.gd

@@ -1,6 +1,6 @@
 extends Node2D
 
 func _ready() -> void:
-	Levels.level_root = $LevelRoot
-	Levels.player = $Player
-	Levels.load_entrypoint("intro_start")
+	NodeRegistry.level_root_container = $LevelRoot
+	NodeRegistry.player = $Player
+	Levels.load_menu()

menu/menu.gd

@@ -0,0 +1,5 @@
+extends Node2D
+
+func _physics_process(_delta: float) -> void:
+	if NodeRegistry.player.position.y > 1000:
+		NodeRegistry.player.position = Vector2(0, 0)

menu/menu.tscn

@@ -0,0 +1,55 @@
+[gd_scene load_steps=4 format=3 uid="uid://bqmpoix37kutp"]
+
+[ext_resource type="PackedScene" uid="uid://cbynoofsjcl45" path="res://core/polygon.tscn" id="1_8p275"]
+[ext_resource type="Script" path="res://menu/menu.gd" id="1_g2w4y"]
+[ext_resource type="PackedScene" uid="uid://c40fli7qcma78" path="res://menu/slot/slot.tscn" id="3_rc4dm"]
+
+[node name="Menu" type="Node2D"]
+position = Vector2(0, -1)
+script = ExtResource("1_g2w4y")
+
+[node name="Label" type="Label" parent="."]
+offset_left = -192.0
+offset_top = -15.0
+offset_right = 192.0
+offset_bottom = 65.0
+theme_override_font_sizes/font_size = 52
+text = "Main Menu"
+horizontal_alignment = 1
+vertical_alignment = 2
+
+[node name="StaticBody2D" type="StaticBody2D" parent="."]
+
+[node name="Polygon" parent="StaticBody2D" instance=ExtResource("1_8p275")]
+polygon = PackedVector2Array(-256, 209, 320, 209, 320, 193, -272, 193, -272, 601, -304, 601, -304, 617, -256, 617)
+
+[node name="SaveGameSlots" type="Node2D" parent="."]
+position = Vector2(-448, 177)
+
+[node name="Saves" type="Label" parent="SaveGameSlots"]
+offset_left = -64.0
+offset_top = -176.0
+offset_right = 64.0
+offset_bottom = -112.0
+theme_override_font_sizes/font_size = 42
+text = "Saves"
+horizontal_alignment = 1
+vertical_alignment = 2
+
+[node name="Slot0" parent="SaveGameSlots" instance=ExtResource("3_rc4dm")]
+slot_label = "0"
+
+[node name="Slot1" parent="SaveGameSlots" instance=ExtResource("3_rc4dm")]
+position = Vector2(0, 128)
+slot_idx = 1
+slot_label = "1"
+
+[node name="Slot2" parent="SaveGameSlots" instance=ExtResource("3_rc4dm")]
+position = Vector2(0, 256)
+slot_idx = 2
+slot_label = "2"
+
+[node name="Slot3" parent="SaveGameSlots" instance=ExtResource("3_rc4dm")]
+position = Vector2(0, 384)
+slot_idx = 3
+slot_label = "3"

menu/slot/slot.gd

@@ -0,0 +1,21 @@
+extends Node2D
+
+@export var slot_idx: int
+@export var slot_label: String = ""
+
+
+func _ready() -> void:
+	$Label.text = str(slot_label)
+
+func _on_area_2d_load_body_entered(body: Node2D) -> void:
+	# load slot & start game
+	if body == NodeRegistry.player:
+		Gamestate.current_slot = slot_idx
+		Gamestate.load_slot()
+		Levels.load_entrypoint(Gamestate.last_entrypoint)
+
+func _on_area_2d_delete_body_entered(body: Node2D) -> void:
+	# reset slot on disk
+	if body == NodeRegistry.player:
+		Gamestate.reset_slot(slot_idx)
+		NodeRegistry.player.position = Levels.mainmenu_player_pos

menu/slot/slot.tscn

@@ -0,0 +1,35 @@
+[gd_scene load_steps=3 format=3 uid="uid://c40fli7qcma78"]
+
+[ext_resource type="PackedScene" uid="uid://cbynoofsjcl45" path="res://core/polygon.tscn" id="1_2cb7u"]
+[ext_resource type="Script" path="res://menu/slot/slot.gd" id="1_3dgi0"]
+
+[node name="Slot" type="Node2D"]
+script = ExtResource("1_3dgi0")
+
+[node name="StaticBody2D" type="StaticBody2D" parent="."]
+
+[node name="platform" parent="StaticBody2D" instance=ExtResource("1_2cb7u")]
+polygon = PackedVector2Array(44, 16, -44, 16, -44, 48, -64, 48, -64, 16, -80, 16, -80, 56, 80, 56, 80, 16, 64, 16, 64, 48, 44, 48)
+
+[node name="Area2D_Load" type="Area2D" parent="."]
+
+[node name="Polygon" parent="Area2D_Load" instance=ExtResource("1_2cb7u")]
+polygon = PackedVector2Array(44, 48, 64, 48, 64, 24, 44, 24)
+color = Color(0, 1, 0, 1)
+
+[node name="Area2D_Delete" type="Area2D" parent="."]
+
+[node name="Polygon" parent="Area2D_Delete" instance=ExtResource("1_2cb7u")]
+polygon = PackedVector2Array(-64, 48, -44, 48, -44, 24, -64, 24)
+color = Color(1, 0, 0, 1)
+
+[node name="Label" type="Label" parent="."]
+offset_left = -16.0
+offset_top = -32.0
+offset_right = 16.0
+text = "_"
+horizontal_alignment = 1
+vertical_alignment = 1
+
+[connection signal="body_entered" from="Area2D_Load" to="." method="_on_area_2d_load_body_entered"]
+[connection signal="body_entered" from="Area2D_Delete" to="." method="_on_area_2d_delete_body_entered"]

player/player.gd

@@ -1,9 +1,16 @@
 extends CharacterBody2D
 
+# die
+
+func die():
+	Levels.load_entrypoint(Gamestate.last_entrypoint)
+
+# movement and stuff
 
 @export var movement_speed = 300.0
 @export var jump_velocity = -350.0
 @export var max_jumps: int = 2
+@export var rigidbody_impulse_mult: float = 0.04
 
 @onready var ceiling_raycast1 = $RayCastUp1
 @onready var ceiling_raycast2 = $RayCastUp2
@@ -34,6 +41,12 @@ func _physics_process(delta: float) -> void:
 			velocity.y = jump_velocity
 			jumps += 1
 	move_and_slide()
-
-func reset_physics():
-	velocity = Vector2.ZERO
+	# affect rigid bodies
+	# adapted solution from
+	# https://kidscancode.org/godot_recipes/4.x/physics/character_vs_rigid/index.html
+	for i in get_slide_collision_count():
+		var collision = get_slide_collision(i)
+		var collider = collision.get_collider()
+		if collider is RigidBody2D:
+			var impulse = -collision.get_normal() * (velocity.length() / collider.mass) * rigidbody_impulse_mult
+			collider.apply_central_impulse(impulse)

project.godot

@@ -19,6 +19,8 @@ config/icon="res://icon.svg"
 [autoload]
 
 Levels="*res://core/globals/levels.gd"
+NodeRegistry="*res://core/globals/node_registry.gd"
+Gamestate="*res://core/globals/gamestate.gd"
 
 [debug]
 
@@ -54,6 +56,8 @@ player_right={
 
 [physics]
 
+common/physics_ticks_per_second=120
+common/max_physics_steps_per_frame=16
 common/physics_jitter_fix=0.0
 2d/physics_engine="Rapier2D"
 common/physics_interpolation=true
@@ -61,6 +65,7 @@ common/physics_interpolation=true
 [rendering]
 
 environment/defaults/default_clear_color=Color(0, 0, 0, 1)
+anti_aliasing/quality/screen_space_aa=1
 anti_aliasing/size/mode=3
 anti_aliasing/stretch/aspect="keep"
 anti_aliasing/stretch/mode="viewport"