Change display scaling logic

Window size in editor is now 640x360
The default 2x scale is now obtained by a hook in Common singleton, using shrink.
Window will snap to integer scales (720p = 2x, 1080p = 3x, 1440p = 4x, 3200x1800 = 5x, 2160p = 6x ...) one second after last window resize

main_menu.tscn

@@ -12,7 +12,6 @@ anchor_right = 1.0
 anchor_bottom = 1.0
 margin_right = -640.0
 margin_bottom = -360.0
-rect_scale = Vector2( 2, 2 )
 theme = ExtResource( 2 )
 
 [node name="party_menu" parent="." instance=ExtResource( 5 )]

project.godot

@@ -37,9 +37,11 @@ gdscript/warnings/integer_division=false
 
 [display]
 
-window/size/width=1280
-window/size/height=720
+window/size/width=640
+window/size/height=360
 window/dpi/allow_hidpi=true
+window/stretch/shrink=2.0
+window/size/snap_to_integer=true
 
 [gui]
 
@@ -57,5 +59,6 @@ texture={
 [rendering]
 
 quality/driver/driver_name="GLES2"
+2d/snapping/use_gpu_pixel_snap=true
 environment/default_clear_color=Color( 0, 0, 0, 1 )
 environment/default_environment="res://default_env.tres"

scripts/loaders/common.gd

@@ -1,5 +1,8 @@
 extends Node
 
+const base_resolution := Vector2(640, 360)
+var shrink_timer := Timer.new()
+
 static func load_json(filename: String) -> Dictionary:
 	var file := File.new()
 	var error := file.open(filename, File.READ)
@@ -36,3 +39,29 @@ static func load_tsv(filename: String, delimiter: String = '\t') -> Dictionary:
 	return {}
 
 var SNES_PSX_addresses := load_tsv('res://data/SNES_PSX_addresses.tsv')
+
+func shrink_to_integer():
+	var size := OS.get_window_size()
+	var scale_vec := size / base_resolution
+	var scale_f := max(min(scale_vec.x, scale_vec.y), 1)
+	var scale := int(scale_f)
+	OS.window_size = base_resolution*scale
+
+func update_window_scale():
+	if OS.window_size < base_resolution*2:
+		OS.window_size = base_resolution*2
+	var size := OS.get_window_size()
+	var scale_vec := size / base_resolution
+	var scale_f := max(min(scale_vec.x, scale_vec.y), 1)
+	var scale := int(scale_f)
+	if ProjectSettings.get_setting('display/window/size/snap_to_integer'):
+		# OS.window_size = base_resolution*scale
+		shrink_timer.paused = false
+		shrink_timer.start(1)
+	get_tree().set_screen_stretch(SceneTree.STRETCH_MODE_DISABLED, SceneTree.STRETCH_ASPECT_KEEP, base_resolution*scale, scale)
+
+func _ready():
+	shrink_timer.connect('timeout', self, 'shrink_to_integer')
+	add_child(shrink_timer)
+	get_tree().connect('screen_resized', self, 'update_window_scale')
+	OS.set_min_window_size(base_resolution*2)