From 0f3fc12144709cf5f730273e1da82007e4964ad3 Mon Sep 17 00:00:00 2001
From: Chris Latham <backwardspy@gmail.com>
Date: Wed, 9 Sep 2020 16:07:08 +0100
Subject: [PATCH] implement transit instead of ad-hoc fades and improve
 singleton usage

---
 mobs/Spawner.gd           |  3 +--
 player/BonusMan.gd        |  3 +--
 player/Player.gd          |  6 ++----
 project.godot             |  1 +
 states/About.tscn         |  6 +-----
 states/Game.gd            | 24 ++-------------------
 states/Game.tscn          | 23 ++++----------------
 states/GameEnd.gd         | 21 +------------------
 states/GameEnd.tscn       | 17 +--------------
 states/GameOver.gd        | 34 +++++-------------------------
 states/GameOver.tscn      | 13 +-----------
 states/Menu.gd            | 37 ++------------------------------
 states/Menu.tscn          | 16 ++------------
 transit/Transit.gd        | 44 +++++++++++++++++++++++++++++++++++++++
 transit/Transit.tscn      | 42 +++++++++++++++++++++++++++++++++++++
 ui/ScrapAmount.gd         |  2 +-
 ui/about/About.gd         |  6 ++++--
 ui/game/UpgradeShop.gd    |  8 +++----
 ui/game_end/KillsLabel.gd |  4 +---
 ui/game_end/Score.gd      |  4 +---
 ui/game_end/ScrapLabel.gd |  4 +---
 weapons/Weapon.gd         |  1 -
 22 files changed, 121 insertions(+), 198 deletions(-)
 create mode 100644 transit/Transit.gd
 create mode 100644 transit/Transit.tscn

diff --git a/mobs/Spawner.gd b/mobs/Spawner.gd
index 8f5c427..2037ff6 100644
--- a/mobs/Spawner.gd
+++ b/mobs/Spawner.gd
@@ -17,7 +17,6 @@ onready var _spawn_points := get_children()
 onready var _player := get_node(player_path)
 onready var _upgrade_shop: CanvasItem = get_node(upgrade_shop_path)
 onready var _spawn_timer: Timer = get_node("../SpawnTimer")
-onready var _score_tracker: ScoreTracker = get_node("/root/ScoreTracker")
 
 var _endless_mode := false
 var _wave_difficulty := 1
@@ -67,7 +66,7 @@ func _end_wave():
 
 func _on_mob_death():
     _died_this_wave += 1
-    _score_tracker.add_mob_kill()
+    ScoreTracker.add_mob_kill()
 
     if not _endless_mode and _died_this_wave >= _max_mobs:
         _end_wave()
diff --git a/player/BonusMan.gd b/player/BonusMan.gd
index 807e079..50c0295 100644
--- a/player/BonusMan.gd
+++ b/player/BonusMan.gd
@@ -2,7 +2,6 @@ extends Node
 
 export var initial_bonus := 30
 
-onready var _wallet: Wallet = $"/root/Wallet"
 onready var _label: Label = $"../UI/Control/ScrapBonusBox/BonusLabel"
 onready var _timer: Timer = $Timer
 
@@ -28,4 +27,4 @@ func _on_Spawner_wave_started(difficulty: int):
 func _on_Spawner_wave_ended():
     _timer.stop()
     if _bonus > 0:
-        _wallet.add_scrap(_bonus)
+        Wallet.add_scrap(_bonus)
diff --git a/player/Player.gd b/player/Player.gd
index bcde9b2..2f79b2c 100644
--- a/player/Player.gd
+++ b/player/Player.gd
@@ -17,8 +17,6 @@ var _dead := false
 var _weapons_added := 0
 
 onready var _health := max_health
-onready var _wallet: Wallet = get_node("/root/Wallet")
-onready var _score_tracker: ScoreTracker = get_node("/root/ScoreTracker")
 
 func hurt(damage: float):
     if _dead:
@@ -121,8 +119,8 @@ func _process(dt: float):
 func _on_LootSuccArea_body_entered(body):
     if body is Scrap:
         body.succ(self)
-        _wallet.add_scrap(1)
-        _score_tracker.add_scrap_earned(1)
+        Wallet.add_scrap(1)
+        ScoreTracker.add_scrap_earned(1)
 
 func _on_UpgradeShop_upgrade_purchased(upgrade: Upgrade, _final: bool):
     _apply_upgrade(upgrade)
diff --git a/project.godot b/project.godot
index 29b0f20..ef66406 100644
--- a/project.godot
+++ b/project.godot
@@ -82,6 +82,7 @@ config/icon="res://icon.png"
 
 Wallet="*res://player/Wallet.gd"
 ScoreTracker="*res://player/ScoreTracker.gd"
+Transit="*res://transit/Transit.tscn"
 
 [display]
 
diff --git a/states/About.tscn b/states/About.tscn
index eb79f74..7b0719b 100644
--- a/states/About.tscn
+++ b/states/About.tscn
@@ -1,7 +1,6 @@
-[gd_scene load_steps=5 format=2]
+[gd_scene load_steps=4 format=2]
 
 [ext_resource path="res://ui/ui_theme.tres" type="Theme" id=1]
-[ext_resource path="res://effects/Fadein.tscn" type="PackedScene" id=2]
 [ext_resource path="res://ui/about/About.gd" type="Script" id=3]
 [ext_resource path="res://ui/title_font.tres" type="DynamicFont" id=4]
 
@@ -93,8 +92,5 @@ Copyright (c) 2020 backwardspy"
 __meta__ = {
 "_edit_use_anchors_": false
 }
-
-[node name="Fadein" parent="." instance=ExtResource( 2 )]
-visible = false
 [connection signal="pressed" from="BackButton" to="." method="back_to_menu"]
 [connection signal="meta_clicked" from="AboutInfo" to="." method="_on_AboutInfo_meta_clicked"]
diff --git a/states/Game.gd b/states/Game.gd
index c081ef3..239c357 100644
--- a/states/Game.gd
+++ b/states/Game.gd
@@ -1,9 +1,5 @@
 extends Node2D
 
-onready var _score_tracker: ScoreTracker = get_node("/root/ScoreTracker")
-onready var _blackout: ColorRect = $UI/Blackout
-onready var _tween: Tween = $Tween
-
 var _in_endless_wave := false
 
 func handle_player_death():
@@ -12,27 +8,11 @@ func handle_player_death():
 
 func quit_to(scene: String):
     $MusicMan.fade_out()
-
-    _blackout.visible = true
-    var _r := _tween.interpolate_property(
-        _blackout,
-        "color:a",
-        0,
-        1,
-        3,
-        Tween.TRANS_LINEAR,
-        Tween.EASE_IN
-    )
-    _r = _tween.start()
-    yield(_tween, "tween_all_completed")
-
-    var err := get_tree().change_scene(scene)
-    if err:
-        push_error("failed to change to %s scene: %s" % [scene, err])
+    Transit.change_scene(scene, 1.0)
 
 func _ready():
     randomize()
-    get_node("/root/Wallet").empty()
+    Wallet.empty()
 
 func _on_Player_died():
     call_deferred("handle_player_death")
diff --git a/states/Game.tscn b/states/Game.tscn
index 0ad4928..f80cc97 100644
--- a/states/Game.tscn
+++ b/states/Game.tscn
@@ -1,4 +1,4 @@
-[gd_scene load_steps=27 format=2]
+[gd_scene load_steps=26 format=2]
 
 [ext_resource path="res://player/Player.tscn" type="PackedScene" id=1]
 [ext_resource path="res://sprites.png" type="Texture" id=2]
@@ -12,7 +12,6 @@
 [ext_resource path="res://ui/game/UpgradeShop.tscn" type="PackedScene" id=10]
 [ext_resource path="res://ui/GameAnimations.gd" type="Script" id=11]
 [ext_resource path="res://tileset.tres" type="TileSet" id=12]
-[ext_resource path="res://effects/Fadein.tscn" type="PackedScene" id=13]
 [ext_resource path="res://music/TremLoadingloopl.ogg" type="AudioStream" id=14]
 [ext_resource path="res://effects/MusicMan.gd" type="Script" id=15]
 [ext_resource path="res://upgrades/UpgradeManager.tscn" type="PackedScene" id=16]
@@ -117,8 +116,6 @@ script = ExtResource( 5 )
 [node name="WorldEnvironment" type="WorldEnvironment" parent="."]
 environment = SubResource( 1 )
 
-[node name="Tween" type="Tween" parent="."]
-
 [node name="MusicMan" type="Node" parent="."]
 script = ExtResource( 15 )
 
@@ -319,27 +316,15 @@ upgrade_manager_path = NodePath("../../../UpgradeManager")
 [node name="PauseMenu" parent="UI/Control" instance=ExtResource( 18 )]
 pause_mode = 2
 visible = false
-
-[node name="Blackout" type="ColorRect" parent="UI"]
-visible = false
-anchor_right = 1.0
-anchor_bottom = 1.0
-color = Color( 0, 0, 0, 0 )
-__meta__ = {
-"_edit_use_anchors_": false
-}
-
-[node name="Fadein" parent="UI" instance=ExtResource( 13 )]
-visible = false
 [connection signal="timeout" from="BonusMan/Timer" to="BonusMan" method="_on_Timer_timeout"]
 [connection signal="died" from="Player" to="." method="_on_Player_died"]
 [connection signal="health_changed" from="Player" to="UI/Control/HealthBar" method="_on_Player_health_changed"]
-[connection signal="wave_ended" from="Spawner" to="MusicMan" method="to_idle"]
 [connection signal="wave_ended" from="Spawner" to="BonusMan" method="_on_Spawner_wave_ended"]
+[connection signal="wave_ended" from="Spawner" to="MusicMan" method="to_idle"]
+[connection signal="wave_started" from="Spawner" to="AnimationPlayer" method="_on_Spawner_wave_started"]
 [connection signal="wave_started" from="Spawner" to="." method="_on_Spawner_wave_started"]
-[connection signal="wave_started" from="Spawner" to="MusicMan" method="to_battle"]
 [connection signal="wave_started" from="Spawner" to="BonusMan" method="_on_Spawner_wave_started"]
-[connection signal="wave_started" from="Spawner" to="AnimationPlayer" method="_on_Spawner_wave_started"]
+[connection signal="wave_started" from="Spawner" to="MusicMan" method="to_battle"]
 [connection signal="timeout" from="SpawnTimer" to="Spawner" method="spawn"]
 [connection signal="upgrade_purchased" from="UI/Control/UpgradeShop" to="Player" method="_on_UpgradeShop_upgrade_purchased"]
 [connection signal="upgrade_purchased" from="UI/Control/UpgradeShop" to="Spawner" method="_on_UpgradeShop_upgrade_purchased"]
diff --git a/states/GameEnd.gd b/states/GameEnd.gd
index aa7cdac..ab32cdd 100644
--- a/states/GameEnd.gd
+++ b/states/GameEnd.gd
@@ -1,26 +1,7 @@
 extends Control
 
-onready var _tween: Tween = $Tween
-onready var _blackout: ColorRect = $Blackout
-
 func _on_RichTextLabel_meta_clicked(meta: String):
     OS.shell_open(meta)
 
 func _on_MenuButton_pressed():
-    focus_mode = Control.FOCUS_NONE
-    _blackout.visible = true
-    _tween.interpolate_property(
-        _blackout,
-        "color:a",
-        0,
-        1,
-        3,
-        Tween.TRANS_LINEAR,
-        Tween.EASE_IN
-    )
-    _tween.start()
-    yield(_tween, "tween_all_completed")
-
-    var err := get_tree().change_scene("res://states/Menu.tscn")
-    if err:
-        push_error("failed to change to menu scene: %s" % err)
+    Transit.change_scene("res://states/Menu.tscn", 1.0)
diff --git a/states/GameEnd.tscn b/states/GameEnd.tscn
index bc960dd..3da45af 100644
--- a/states/GameEnd.tscn
+++ b/states/GameEnd.tscn
@@ -1,9 +1,8 @@
-[gd_scene load_steps=8 format=2]
+[gd_scene load_steps=7 format=2]
 
 [ext_resource path="res://ui/ui_theme.tres" type="Theme" id=1]
 [ext_resource path="res://ui/title_font.tres" type="DynamicFont" id=2]
 [ext_resource path="res://states/GameEnd.gd" type="Script" id=3]
-[ext_resource path="res://effects/Fadein.tscn" type="PackedScene" id=4]
 [ext_resource path="res://ui/game_end/ScrapLabel.gd" type="Script" id=5]
 [ext_resource path="res://ui/game_end/KillsLabel.gd" type="Script" id=6]
 [ext_resource path="res://ui/game_end/Score.gd" type="Script" id=7]
@@ -20,8 +19,6 @@ __meta__ = {
 "_edit_use_anchors_": false
 }
 
-[node name="Tween" type="Tween" parent="."]
-
 [node name="GameTextBox" type="VBoxContainer" parent="."]
 anchor_left = 0.5
 anchor_right = 0.5
@@ -120,17 +117,5 @@ text = "Return to Menu"
 __meta__ = {
 "_edit_use_anchors_": false
 }
-
-[node name="Fadein" parent="." instance=ExtResource( 4 )]
-visible = false
-
-[node name="Blackout" type="ColorRect" parent="."]
-visible = false
-anchor_right = 1.0
-anchor_bottom = 1.0
-color = Color( 0, 0, 0, 0 )
-__meta__ = {
-"_edit_use_anchors_": false
-}
 [connection signal="meta_clicked" from="MetaTextBox/RichTextLabel" to="." method="_on_RichTextLabel_meta_clicked"]
 [connection signal="pressed" from="MenuButton" to="." method="_on_MenuButton_pressed"]
diff --git a/states/GameOver.gd b/states/GameOver.gd
index 1370634..e72a1b2 100644
--- a/states/GameOver.gd
+++ b/states/GameOver.gd
@@ -1,36 +1,12 @@
 extends Control
 
-onready var _tween: Tween = $Tween
-
-func _fade_to_scene(path: String):
-    focus_mode = Control.FOCUS_NONE
-
-    $Blackout.visible = true
-
-    var _r := _tween.interpolate_property(
-        $Blackout,
-        "color:a",
-        0,
-        1,
-        0.5,
-        Tween.TRANS_LINEAR,
-        Tween.EASE_OUT
-    )
-
-    _r = _tween.start()
-    yield(_tween, "tween_all_completed")
-    var err := get_tree().change_scene(path)
-    if err:
-        push_error("failed to change scene to %s: %s" % [path, err])
-
 func retry():
-    _fade_to_scene("res://states/Game.tscn")
+    Transit.change_scene("res://states/Game.tscn", 1.0)
 
 func menu():
-    _fade_to_scene("res://states/Menu.tscn")
+    Transit.change_scene("res://states/Menu.tscn", 1.0)
 
 func _ready():
-    var scores: ScoreTracker = get_node("/root/ScoreTracker")
-    $ControlsBox/ScrapEarned.text = "You earned %s Scrap" % scores.get_scrap_earned()
-    $ControlsBox/MobsKilled.text = "You killed %s drones" % scores.get_mobs_killed()
-    $ControlsBox/Score.text = "Score: %s" % scores.calculate_score()
+    $ControlsBox/ScrapEarned.text = "You earned %s Scrap" % ScoreTracker.get_scrap_earned()
+    $ControlsBox/MobsKilled.text = "You killed %s drones" % ScoreTracker.get_mobs_killed()
+    $ControlsBox/Score.text = "Score: %s" % ScoreTracker.calculate_score()
diff --git a/states/GameOver.tscn b/states/GameOver.tscn
index 733b47c..6b5d538 100644
--- a/states/GameOver.tscn
+++ b/states/GameOver.tscn
@@ -1,9 +1,8 @@
-[gd_scene load_steps=5 format=2]
+[gd_scene load_steps=4 format=2]
 
 [ext_resource path="res://states/GameOver.gd" type="Script" id=1]
 [ext_resource path="res://ui/ui_theme.tres" type="Theme" id=2]
 [ext_resource path="res://ui/title_font.tres" type="DynamicFont" id=3]
-[ext_resource path="res://effects/Fadein.tscn" type="PackedScene" id=4]
 
 [node name="Root" type="Control"]
 anchor_right = 1.0
@@ -17,8 +16,6 @@ __meta__ = {
 "_edit_use_anchors_": false
 }
 
-[node name="Tween" type="Tween" parent="."]
-
 [node name="ControlsBox" type="VBoxContainer" parent="."]
 anchor_left = 0.5
 anchor_top = 0.5
@@ -74,13 +71,5 @@ text = "Menu"
 __meta__ = {
 "_edit_use_anchors_": false
 }
-
-[node name="Fadein" parent="." instance=ExtResource( 4 )]
-
-[node name="Blackout" type="ColorRect" parent="."]
-visible = false
-anchor_right = 1.0
-anchor_bottom = 1.0
-color = Color( 0, 0, 0, 0 )
 [connection signal="pressed" from="ControlsBox/Retry" to="." method="retry"]
 [connection signal="pressed" from="ControlsBox/QuitToMenu" to="." method="menu"]
diff --git a/states/Menu.gd b/states/Menu.gd
index 7a0ae2f..13b02d3 100644
--- a/states/Menu.gd
+++ b/states/Menu.gd
@@ -1,43 +1,10 @@
 extends Control
 
-onready var _tween := $Tween
-
-func fade_to_scene(path: String):
-    focus_mode = Control.FOCUS_NONE
-
-    $Blackout.visible = true
-
-    _tween.interpolate_property(
-        $Blackout,
-        "color:a",
-        0,
-        1,
-        0.5,
-        Tween.TRANS_LINEAR,
-        Tween.EASE_OUT
-    )
-
-    _tween.interpolate_property(
-        $AudioStreamPlayer,
-        "volume_db",
-        0,
-        -80,
-        0.5,
-        Tween.TRANS_LINEAR,
-        Tween.EASE_IN
-    )
-
-    _tween.start()
-    yield(_tween, "tween_all_completed")
-    var err = get_tree().change_scene(path)
-    if err:
-        push_error("failed to load scene %s: %s" % [path, err])
-
 func start_game():
-    fade_to_scene("res://states/Game.tscn")
+    Transit.change_scene("res://states/Game.tscn", 1.0)
 
 func about():
-    fade_to_scene("res://states/About.tscn")
+    Transit.change_scene("res://states/About.tscn")
 
 func quit_game():
     get_tree().quit()
diff --git a/states/Menu.tscn b/states/Menu.tscn
index 1dba87d..100d1c0 100644
--- a/states/Menu.tscn
+++ b/states/Menu.tscn
@@ -1,4 +1,4 @@
-[gd_scene load_steps=15 format=2]
+[gd_scene load_steps=14 format=2]
 
 [ext_resource path="res://states/Menu.gd" type="Script" id=1]
 [ext_resource path="res://ui/ui_theme.tres" type="Theme" id=2]
@@ -12,7 +12,6 @@
 [ext_resource path="res://ui/menu/TitleBob.gd" type="Script" id=10]
 [ext_resource path="res://music/Factory.ogg" type="AudioStream" id=11]
 [ext_resource path="res://tileset.tres" type="TileSet" id=12]
-[ext_resource path="res://effects/Fadein.tscn" type="PackedScene" id=13]
 [ext_resource path="res://ui/question_mark.png" type="Texture" id=14]
 
 [node name="Root" type="Control"]
@@ -31,8 +30,6 @@ __meta__ = {
 stream = ExtResource( 11 )
 autoplay = true
 
-[node name="Tween" type="Tween" parent="."]
-
 [node name="TileMap" type="TileMap" parent="."]
 tile_set = ExtResource( 12 )
 cell_size = Vector2( 16, 16 )
@@ -143,16 +140,7 @@ flat = true
 __meta__ = {
 "_edit_use_anchors_": false
 }
-
-[node name="Blackout" type="ColorRect" parent="."]
-visible = false
-anchor_right = 1.0
-anchor_bottom = 1.0
-color = Color( 0, 0, 0, 0 )
-
-[node name="Fadein" parent="." instance=ExtResource( 13 )]
-visible = false
 [connection signal="pressed" from="Buttons/StartGame" to="." method="start_game"]
-[connection signal="pressed" from="Buttons/QuitGame" to="." method="quit_game"]
 [connection signal="pressed" from="Buttons/QuitGame" to="." method="start_game"]
+[connection signal="pressed" from="Buttons/QuitGame" to="." method="quit_game"]
 [connection signal="pressed" from="About" to="." method="about"]
diff --git a/transit/Transit.gd b/transit/Transit.gd
new file mode 100644
index 0000000..03003b0
--- /dev/null
+++ b/transit/Transit.gd
@@ -0,0 +1,44 @@
+extends Control
+
+signal scene_changed
+
+const DEFAULT_DURATION := 0.2
+const DEFAULT_DELAY := 0.0
+
+onready var _animator := $AnimationPlayer
+onready var _curtain := $CanvasLayer/ColorRect
+
+func set_color(color: Color):
+    color.a = _curtain.color.a
+    _curtain.color = color
+
+func change_scene(path: String, duration: float = DEFAULT_DURATION, delay: float = DEFAULT_DELAY):
+    if duration <= 0.0:
+        push_error("TRANSIT ERROR: change_scene duration must be > 0. Defaulting to %s" % DEFAULT_DURATION)
+        duration = DEFAULT_DURATION
+
+    if delay < 0.0:
+        push_error("TRANSIT ERROR: change_scene delay must be >= 0. Defaulting to %s" % DEFAULT_DELAY)
+        delay = DEFAULT_DELAY
+
+    # disable mouse interaction while fading out
+    _curtain.mouse_filter = MOUSE_FILTER_STOP
+
+    if delay > 0:
+        yield(get_tree().create_timer(delay), "timeout")
+
+    _animator.playback_speed = 1.0 / duration
+    _animator.play("fade")
+    yield(_animator, "animation_finished")
+
+    var err := get_tree().change_scene(path)
+    if err:
+        push_error("TRANSIT ERROR: Failed to change scene to %s: %s" % [path, err])
+
+    # re-enable mouse interaction before fading back in
+    _curtain.mouse_filter = MOUSE_FILTER_IGNORE
+
+    _animator.play_backwards("fade")
+    yield(_animator, "animation_finished")
+
+    emit_signal("scene_changed")
diff --git a/transit/Transit.tscn b/transit/Transit.tscn
new file mode 100644
index 0000000..798d0d3
--- /dev/null
+++ b/transit/Transit.tscn
@@ -0,0 +1,42 @@
+[gd_scene load_steps=3 format=2]
+
+[ext_resource path="res://transit/Transit.gd" type="Script" id=1]
+
+[sub_resource type="Animation" id=1]
+resource_name = "fade"
+step = 0.2
+tracks/0/type = "value"
+tracks/0/path = NodePath("CanvasLayer/ColorRect:color:a")
+tracks/0/interp = 1
+tracks/0/loop_wrap = true
+tracks/0/imported = false
+tracks/0/enabled = true
+tracks/0/keys = {
+"times": PoolRealArray( 0, 1 ),
+"transitions": PoolRealArray( 1, 1 ),
+"update": 0,
+"values": [ 0.0, 1.0 ]
+}
+
+[node name="Transit" type="Control"]
+anchor_right = 1.0
+anchor_bottom = 1.0
+script = ExtResource( 1 )
+__meta__ = {
+"_edit_use_anchors_": false
+}
+
+[node name="AnimationPlayer" type="AnimationPlayer" parent="."]
+anims/fade = SubResource( 1 )
+
+[node name="CanvasLayer" type="CanvasLayer" parent="."]
+layer = 128
+
+[node name="ColorRect" type="ColorRect" parent="CanvasLayer"]
+anchor_right = 1.0
+anchor_bottom = 1.0
+mouse_filter = 2
+color = Color( 0, 0, 0, 0 )
+__meta__ = {
+"_edit_use_anchors_": false
+}
diff --git a/ui/ScrapAmount.gd b/ui/ScrapAmount.gd
index 2e31bb2..dafc1c3 100644
--- a/ui/ScrapAmount.gd
+++ b/ui/ScrapAmount.gd
@@ -4,6 +4,6 @@ func _on_scrap_changed(amount: int):
     text = "x %s" % amount
 
 func _ready():
-    var err := get_node("/root/Wallet").connect("scrap_changed", self, "_on_scrap_changed")
+    var err := Wallet.connect("scrap_changed", self, "_on_scrap_changed")
     if err:
         push_error("failed to connect wallet scrap_changed signal: %s" % err)
diff --git a/ui/about/About.gd b/ui/about/About.gd
index 4b28230..60b3611 100644
--- a/ui/about/About.gd
+++ b/ui/about/About.gd
@@ -1,7 +1,9 @@
 extends Control
 
 func back_to_menu():
-    get_tree().change_scene("res://states/Menu.tscn")
+    Transit.change_scene("res://states/Menu.tscn")
 
 func _on_AboutInfo_meta_clicked(meta):
-    OS.shell_open(meta)
+    var err := OS.shell_open(meta)
+    if err:
+        push_error("Failed to open %s: %s" % [meta, err])
diff --git a/ui/game/UpgradeShop.gd b/ui/game/UpgradeShop.gd
index b150063..d03fdbf 100644
--- a/ui/game/UpgradeShop.gd
+++ b/ui/game/UpgradeShop.gd
@@ -6,8 +6,6 @@ signal wave_repeated
 export(NodePath) var upgrade_manager_path: NodePath
 onready var _upgrade_man: UpgradeManager = get_node(upgrade_manager_path)
 
-onready var _wallet: Wallet = get_node("/root/Wallet")
-
 const upgrade_button_scene = preload("res://ui/game/UpgradeButton.tscn")
 
 # track which upgrades have been bought to allow for requirements validation
@@ -23,7 +21,7 @@ func _on_Repeat_pressed():
     emit_signal("wave_repeated")
 
 func _on_upgrade_chosen(upgrade: Upgrade):
-    if not _wallet.try_remove_scrap(upgrade.price):
+    if not Wallet.try_remove_scrap(upgrade.price):
         return  # TODO: some sort of notification/sound effect?
 
     _bought_slugs.append(upgrade.slug)
@@ -42,9 +40,9 @@ func show():
         var reqs_met := _requirements_met(upgrade)
 
         var b: UpgradeButton = upgrade_button_scene.instance()
-        b.apply_upgrade(upgrade, _wallet.get_balance(), reqs_met)
+        b.apply_upgrade(upgrade, Wallet.get_balance(), reqs_met)
 
-        var err := _wallet.connect("scrap_changed", b, "check_scrap_adequacy")
+        var err := Wallet.connect("scrap_changed", b, "check_scrap_adequacy")
         if err:
             push_error("failed to connect wallet scrap_changed signal: %s" % err)
             return
diff --git a/ui/game_end/KillsLabel.gd b/ui/game_end/KillsLabel.gd
index 6f57c32..ea37999 100644
--- a/ui/game_end/KillsLabel.gd
+++ b/ui/game_end/KillsLabel.gd
@@ -1,6 +1,4 @@
 extends Label
 
-onready var _score: ScoreTracker = get_node("/root/ScoreTracker")
-
 func _ready():
-    text = "You killed %s drones" % _score.get_mobs_killed()
+    text = "You killed %s drones" % ScoreTracker.get_mobs_killed()
diff --git a/ui/game_end/Score.gd b/ui/game_end/Score.gd
index 2a59ed0..33ba11f 100644
--- a/ui/game_end/Score.gd
+++ b/ui/game_end/Score.gd
@@ -1,6 +1,4 @@
 extends Label
 
-onready var _score: ScoreTracker = get_node("/root/ScoreTracker")
-
 func _ready():
-    text = "Score: %s" % _score.calculate_score()
+    text = "Score: %s" % ScoreTracker.calculate_score()
diff --git a/ui/game_end/ScrapLabel.gd b/ui/game_end/ScrapLabel.gd
index 27266c1..0cedaaf 100644
--- a/ui/game_end/ScrapLabel.gd
+++ b/ui/game_end/ScrapLabel.gd
@@ -1,6 +1,4 @@
 extends Label
 
-onready var _score: ScoreTracker = get_node("/root/ScoreTracker")
-
 func _ready():
-    text = "You earned %s Scrap" % _score.get_scrap_earned()
+    text = "You earned %s Scrap" % ScoreTracker.get_scrap_earned()
diff --git a/weapons/Weapon.gd b/weapons/Weapon.gd
index 47630ad..04ca6c7 100644
--- a/weapons/Weapon.gd
+++ b/weapons/Weapon.gd
@@ -9,7 +9,6 @@ export var reduces_volume_on_add := false
 onready var _timer := $FireTimer
 
 func reduce_volume(times: int = 1):
-    var old_vol: float = $AudioPlayer.volume_db
     $AudioPlayer.volume_db -= 3.0 * times
 
 func fire():