Add a demo on supporting multiple resolutions and aspect ratios

This demo intends to showcase what Godot can do in terms of supporting
multiple resolutions and aspect ratios.

Author: Calinou

gui/multiple_resolutions/README.md

@@ -0,0 +1,94 @@
+# Multiple Resolutions and Aspect Ratios
+
+**Note:** This demo is intended to showcase what Godot can do in terms of
+supporting multiple resolutions and aspect ratios. As such, this demo very
+full-featured but it's also fairly complex to understand.
+
+If you're in a hurry and want to implement *decent* support for multiple
+resolutions and aspect ratios in your game, see [Multiple resolutions crash
+course](#multiple-resolutions-crash-course).
+
+___
+
+This project demonstrates how to set up a project to handle screens of multiple
+resolutions and aspect ratios.
+
+This demo allows you to adjust the window's base resolution, stretch mode,
+stretch aspect, and scale factor (internally known as "stretch shrink"). This
+lets you see what happens when adjusting those properties. Make sure to resize
+the project window in any direction to see the difference with the various
+stretch mode and stretch aspect settings.
+
+The GUI can be made to fit the window or constrained to a specific aspect ratio
+from a list of common aspect ratios. On ultrawide aspect ratios, this can be
+used to prevent HUD elements from being too spread apart, which can harm the
+gameplay experience. For non-essential HUD elements, specific controls can be
+made to ignore this aspect ratio constraint when it makes sense (e.g. a list of
+players on the side of the screen).
+
+Additionally, a GUI margin setting is provided to better handle TVs with an
+overscan area to prevent GUI elements from being cut off. This can also improve
+the gameplay experience on large monitors by bringing HUD elements closer to the
+center of the screen.
+
+A DynamicFont is also used to ensure font rendering remains crisp at high
+resolutions, thanks to Godot's built-in support for font oversampling. In other
+words, the engine will automatically re-rasterize fonts at different resolutions
+than the base window size when the window is resized (or when the window scale
+factor is changed).
+
+Language: GDScript
+
+Renderer: GLES 2
+
+## Technical notes
+
+The demo works with the following project settings:
+
+- `2d` stretch mode (recommended for most non-pixel art games).
+- `expand` stretch aspect (allows support for multiple aspect ratios without
+  distortion or black bars).
+- Using a base window size with a 1:1 aspect ratio (`648×648` in this demo).
+  This prevents GUI elements from automatically shrinking, even in portrait
+  mode.
+  - With this setting, to prevent the GUI from breaking at narrow aspect ratios,
+    the GUI must be designed to work with a 1:1 aspect ratio. This is not
+    feasible in most complex games, so a base window size with a wider aspect
+    ratio (such as 4:3 or 16:10) can be used instead. The wider the aspect
+    ratio, the easier design becomes, but the GUI will automatically become
+    smaller at narrow aspect ratios unless the user overrides its scale with the
+    stretch shrink setting. Many devices such as the Steam Deck and MacBooks
+    feature 16:10 displays, so it's recommended to use a 16:10 resolution or
+    narrower as a base window size to ensure a good gameplay experience out of
+    the box on those devices.
+- Using a test window size with a 16:9 aspect ratio (`1152×648` in this demo).
+  This way, the project starts in a 16:9 window even if the base window size has
+  a 1:1 aspect ratio.
+  - The test window height matches the width and height of the base window size,
+    so GUI elements are still at the same size.
+
+## Multiple resolutions crash course
+
+**Not everything in this demo is critical to all games.** For gamejam projects or mobile games, most of this can be skipped.
+See the [Common use case scenarios](https://docs.godotengine.org/en/stable/tutorials/rendering/multiple_resolutions.html#common-use-case-scenarios)
+section in the Multiple resolutions documentation.
+
+With the simpler setup described in the above documentation, there are a few
+limitations compared to this demo:
+
+- The HUD will shrink when the aspect ratio becomes narrower than the base
+  window size. As such, it's recommended to use a base window size with a 16:10
+  aspect ratio to prevent the HUD from shrinking on Steam Deck and MacBooks.
+- Players will not be able to define a margin, which can be problematic when
+  playing on a TV (as overscan can obstruct some HUD elements). This can be
+  worked around by ensuring the entire HUD always has a small margin around it.
+  This can be done by increasing the Margin properties on all sides on the root
+  Control node by 10-30 pixels or so.
+
+If you're releasing a full-fledged game on a desktop platform such as Steam,
+consider implementing full support as this demo suggests. Your players will
+thank you :slightly_smiling_face:
+
+## Screenshots
+
+![Screenshot](screenshots/multiple_resolutions.png)

gui/multiple_resolutions/icon.png

@@ -0,0 +1,35 @@
+[remap]
+
+importer="texture"
+type="StreamTexture"
+path="res://.import/icon.png-487276ed1e3a0c39cad0279d744ee560.stex"
+metadata={
+"vram_texture": false
+}
+
+[deps]
+
+source_file="res://icon.png"
+dest_files=[ "res://.import/icon.png-487276ed1e3a0c39cad0279d744ee560.stex" ]
+
+[params]
+
+compress/mode=0
+compress/lossy_quality=0.7
+compress/hdr_mode=0
+compress/bptc_ldr=0
+compress/normal_map=0
+flags/repeat=0
+flags/filter=true
+flags/mipmaps=false
+flags/anisotropic=false
+flags/srgb=2
+process/fix_alpha_border=true
+process/premult_alpha=false
+process/HDR_as_SRGB=false
+process/invert_color=false
+process/normal_map_invert_y=false
+stream=false
+size_limit=0
+detect_3d=true
+svg/scale=1.0

gui/multiple_resolutions/icon.png.import

@@ -0,0 +1,129 @@
+# The root Control node ("Main") and AspectRatioContainer nodes are the most important
+# pieces of this demo.
+# Both nodes have their Layout set to Full Rect
+# (with their rect spread across the whole viewport, and Anchor set to Full Rect).
+extends Control
+
+var base_window_size = Vector2(ProjectSettings.get_setting("display/window/size/width"), ProjectSettings.get_setting("display/window/size/height"))
+
+# These defaults match this demo's project settings. Adjust as needed if adapting this
+# in your own project.
+var stretch_mode = SceneTree.STRETCH_MODE_2D
+var stretch_aspect = SceneTree.STRETCH_ASPECT_EXPAND
+
+var scale_factor = 1.0
+var gui_aspect_ratio = -1.0
+var gui_margin = 0.0
+
+onready var panel = $Panel
+onready var arc = $Panel/AspectRatioContainer
+
+
+func _ready():
+	# The `resized` signal will be emitted when the window size changes, as the root Control node
+	# is resized whenever the window size changes. This is because the root Control node
+	# uses a Full Rect anchor, so its size will always be equal to the window size.
+	# warning-ignore:return_value_discarded
+	connect("resized", self, "_on_resized")
+	update_container()
+
+
+func update_container():
+	# The code within this function needs to be run twice to work around an issue with containers
+	# having a 1-frame delay with updates.
+	# Otherwise, `panel.rect_size` returns a value of the previous frame, which results in incorrect
+	# sizing of the inner AspectRatioContainer when using the Fit to Window setting.
+	for _i in 2:
+		if is_equal_approx(gui_aspect_ratio, -1.0):
+			# Fit to Window. Tell the AspectRatioContainer to use the same aspect ratio as the window,
+			# making the AspectRatioContainer not have any visible effect.
+			arc.ratio = panel.rect_size.aspect()
+			# Apply GUI margin on the AspectRatioContainer's parent (Panel).
+			# This also makes the GUI margin apply on controls located outside the AspectRatioContainer
+			# (such as the inner side label in this demo).
+			panel.margin_top = gui_margin
+			panel.margin_bottom = -gui_margin
+		else:
+			# Constrained aspect ratio.
+			arc.ratio = min(panel.rect_size.aspect(), gui_aspect_ratio)
+			# Adjust top and bottom margins relative to the aspect ratio when it's constrained.
+			# This ensures that GUI margin settings behave exactly as if the window had the
+			# original aspect ratio size.
+			panel.margin_top = gui_margin / gui_aspect_ratio
+			panel.margin_bottom = -gui_margin / gui_aspect_ratio
+
+		panel.margin_left = gui_margin
+		panel.margin_right = -gui_margin
+
+
+func _on_gui_aspect_ratio_item_selected(index):
+	match index:
+		0:  # Fit to Window
+			gui_aspect_ratio = -1.0
+		1:  # 5:4
+			gui_aspect_ratio = 5.0 / 4.0
+		2:  # 4:3
+			gui_aspect_ratio = 4.0 / 3.0
+		3:  # 3:2
+			gui_aspect_ratio = 3.0 / 2.0
+		4:  # 16:10
+			gui_aspect_ratio = 16.0 / 10.0
+		5:  # 16:9
+			gui_aspect_ratio = 16.0 / 9.0
+		6:  # 21:9
+			gui_aspect_ratio = 21.0 / 9.0
+
+	update_container()
+
+
+func _on_resized():
+	update_container()
+
+
+func _on_gui_margin_drag_ended(_value_changed):
+	gui_margin = $"Panel/AspectRatioContainer/ColorRect/CenterContainer/Options/GUIMargin/HSlider".value
+	$"Panel/AspectRatioContainer/ColorRect/CenterContainer/Options/GUIMargin/Value".text = str(gui_margin)
+	update_container()
+
+
+func _on_window_base_size_item_selected(index):
+	match index:
+		0:  # 648×648 (1:1)
+			base_window_size = Vector2(648, 648)
+		1:  # 640×480 (4:3)
+			base_window_size = Vector2(640, 480)
+		2:  # 720×480 (3:2)
+			base_window_size = Vector2(720, 480)
+		3:  # 800×600 (4:3)
+			base_window_size = Vector2(800, 600)
+		4:  # 1152×648 (16:9)
+			base_window_size = Vector2(1152, 648)
+		5:  # 1280×720 (16:9)
+			base_window_size = Vector2(1280, 720)
+		6:  # 1280×800 (16:10)
+			base_window_size = Vector2(1280, 800)
+		7:  # 1680×720 (21:9)
+			base_window_size = Vector2(1680, 720)
+
+	get_tree().set_screen_stretch(stretch_mode, stretch_aspect, base_window_size, scale_factor)
+	update_container()
+
+
+func _on_window_stretch_mode_item_selected(index):
+	stretch_mode = index
+	get_tree().set_screen_stretch(stretch_mode, stretch_aspect, base_window_size, scale_factor)
+
+	# Disable irrelevant options when the stretch mode is Disabled.
+	$"Panel/AspectRatioContainer/ColorRect/CenterContainer/Options/WindowBaseSize/OptionButton".disabled = stretch_mode == SceneTree.STRETCH_MODE_DISABLED
+	$"Panel/AspectRatioContainer/ColorRect/CenterContainer/Options/WindowStretchAspect/OptionButton".disabled = stretch_mode == SceneTree.STRETCH_MODE_DISABLED
+
+
+func _on_window_stretch_aspect_item_selected(index):
+	stretch_aspect = index
+	get_tree().set_screen_stretch(stretch_mode, stretch_aspect, base_window_size, scale_factor)
+
+
+func _on_window_scale_factor_drag_ended(_value_changed):
+	scale_factor = $"Panel/AspectRatioContainer/ColorRect/CenterContainer/Options/WindowScaleFactor/HSlider".value
+	$"Panel/AspectRatioContainer/ColorRect/CenterContainer/Options/WindowScaleFactor/Value".text = "%d%%" % (scale_factor * 100)
+	get_tree().set_screen_stretch(stretch_mode, stretch_aspect, base_window_size, scale_factor)