Added bg_sound manager and according ESC command.

Started transitions scene.

addons/escoria-core/game/scenes/transitions/transition.gd

@@ -0,0 +1,28 @@
+extends ColorRect
+
+export(String, "fade_black", "fade_white", "transition_in", "transition_out") var transition_name
+# Reference to the _AnimationPlayer_ node
+onready var _anim_player := $AnimationPlayer
+
+
+
+signal transition_done
+
+
+func _ready() -> void:
+	# Plays the animation backward to fade in
+	_anim_player.play_backwards(transition_name)
+
+
+func fade_out() -> void:
+	# Plays the Fade animation and wait until it finishes
+	_anim_player.play(transition_name)
+	yield(_anim_player, "animation_finished")
+	emit_signal("transition_done")
+
+func fade_in() -> void:
+	# Plays the Fade animation and wait until it finishes
+	_anim_player.play_backwards(transition_name)
+	yield(_anim_player, "animation_finished")
+	emit_signal("transition_done")
+

addons/escoria-core/game/scenes/transitions/transition.tscn

@@ -0,0 +1,83 @@
+[gd_scene load_steps=7 format=2]
+
+[ext_resource path="res://addons/escoria-core/game/scenes/transitions/transition.gd" type="Script" id=1]
+[ext_resource path="res://addons/escoria-core/game/scenes/transitions/shaders/transition.material" type="Material" id=2]
+
+[sub_resource type="Animation" id=1]
+resource_name = "fade_black"
+length = 0.5
+tracks/0/type = "value"
+tracks/0/path = NodePath(".:modulate")
+tracks/0/interp = 1
+tracks/0/loop_wrap = true
+tracks/0/imported = false
+tracks/0/enabled = true
+tracks/0/keys = {
+"times": PoolRealArray( 0, 0.5 ),
+"transitions": PoolRealArray( 1, 1 ),
+"update": 0,
+"values": [ Color( 0, 0, 0, 0 ), Color( 0, 0, 0, 1 ) ]
+}
+
+[sub_resource type="Animation" id=2]
+resource_name = "fade_white"
+length = 0.5
+tracks/0/type = "value"
+tracks/0/path = NodePath(".:modulate")
+tracks/0/interp = 1
+tracks/0/loop_wrap = true
+tracks/0/imported = false
+tracks/0/enabled = true
+tracks/0/keys = {
+"times": PoolRealArray( 0, 0.5 ),
+"transitions": PoolRealArray( 1, 1 ),
+"update": 0,
+"values": [ Color( 1, 1, 1, 0 ), Color( 1, 1, 1, 1 ) ]
+}
+
+[sub_resource type="Animation" id=3]
+resource_name = "transition_in"
+tracks/0/type = "value"
+tracks/0/path = NodePath(".:material:shader_param/cutoff")
+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 ]
+}
+
+[sub_resource type="Animation" id=4]
+resource_name = "transition_out"
+tracks/0/type = "value"
+tracks/0/path = NodePath(".:material:shader_param/cutoff")
+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": [ 1.0, 0.0 ]
+}
+
+[node name="scene_transition" type="ColorRect"]
+material = ExtResource( 2 )
+anchor_right = 1.0
+anchor_bottom = 1.0
+mouse_filter = 2
+script = ExtResource( 1 )
+__meta__ = {
+"_edit_use_anchors_": false
+}
+transition_name = "transition_out"
+
+[node name="AnimationPlayer" type="AnimationPlayer" parent="."]
+anims/fade_black = SubResource( 1 )
+anims/fade_white = SubResource( 2 )
+anims/transition_in = SubResource( 3 )
+anims/transition_out = SubResource( 4 )