Fix missing particles on android

classes/particles/fallback_particles.gd

@@ -0,0 +1,82 @@
+class_name FallbackParticles
+extends GPUParticles2D
+## Compatibility class that swaps GPU particles out for CPU particles on devices that don't support it.
+## Might be worth making an engine proposal for this kind of thing, since this is somewhat hacky.
+
+## Flags that ensure that the property is editor-accessible and also stored in the scene file.
+## If it's not both of those, then there's no point copying it over.
+const USAGE_FLAGS = 6
+
+## The replacement CPUParticles2D node.
+var _replacement: CPUParticles2D = null
+
+## If true, _set() and _get() will not redirect to the replacement.
+var _dont_redirect: bool = false
+
+
+func _ready():
+	# Check if the device is missing a video adapter (GPU)
+	if OS.get_video_adapter_driver_info().is_empty():
+		# Temporarily disable redirection so we can work.
+		_dont_redirect = true
+
+		# Create a CPU node and copy properties over.
+		_replacement = CPUParticles2D.new()
+		_copy_properties()
+
+		# Replace this node.
+		replace_by.call_deferred(_replacement)
+
+		# Rename the replacement to hide the change.
+		_replacement.name = name
+
+		# Re-enable redirection.
+		_dont_redirect = false
+
+
+## Copy properties from the current node to the replacement.
+func _copy_properties() -> void:
+	_replacement.convert_from_particles(self)
+
+	for property in get_property_list():
+		var prop_name = property.name
+		if property.usage != USAGE_FLAGS:
+			continue
+		if prop_name in _replacement:
+			_replacement.set(prop_name, get(prop_name))
+
+
+## Redirect property setting to the replacement node.
+func _set(property, value):
+	if property == &"_dont_redirect":
+		return false
+
+	if _replacement == null:
+		return false
+
+	_replacement.set(property, value)
+	return true
+
+
+## Redirect property getting to the replacement node.
+func _get(property):
+	if property == &"_dont_redirect":
+		return null
+
+	if _dont_redirect:
+		return null
+
+	if _replacement == null:
+		return null
+
+	if !property in _replacement:
+		return null
+
+	for prop in get_property_list():
+		if prop.name != property:
+			continue
+
+		if prop.usage != USAGE_FLAGS:
+			return null
+
+	return _replacement.get(property)

classes/particles/generic_particles.gd

@@ -0,0 +1,10 @@
+class_name GenericParticles2D
+extends Node2D
+## Generic class for GPUParticles2D and CPUParticles2D
+
+var g_emitting: bool = false:
+	set(value):
+		set(&"emitting", value)
+		g_emitting = value
+	get:
+		return get(&"emitting")

classes/pickup/coin/coin_particles.gd

@@ -1,10 +1,10 @@
-extends GPUParticles2D
+extends GenericParticles2D
 
 
 func _ready():
-	emitting = true
+	g_emitting = true
 
 
 func _process(_delta):
-	if !emitting:
+	if !g_emitting:
 		queue_free()

classes/pickup/coin/coin_pickup.gd

@@ -29,7 +29,7 @@ func _add_coins(num: int, player: PlayerCharacter) -> void:
 
 func _pickup_effect() -> void:
 	Singleton.get_node("SFX/Coin").play()
-	var inst: GPUParticles2D = PARTICLE_SCENE.instantiate()
+	var inst = PARTICLE_SCENE.instantiate()
 	inst.texture = particle_texture
 	if parent_is_root:
 		inst.position = get_parent().position

gui/water_meter/water_meter.gd

@@ -14,9 +14,9 @@ var icon_bob = 0
 @onready var filler: Sprite2D = $Filler
 @onready var surface: Sprite2D = $Surface
 @onready var bubble_mask: NinePatchRect = $BubbleMask
-@onready var bubbles_big: GPUParticles2D = $BubbleMask/BubblesBig
-@onready var bubbles_medium: GPUParticles2D = $BubbleMask/BubblesMedium
-@onready var bubbles_small: GPUParticles2D = $BubbleMask/BubblesSmall
+@onready var bubbles_big = $BubbleMask/BubblesBig
+@onready var bubbles_medium = $BubbleMask/BubblesMedium
+@onready var bubbles_small = $BubbleMask/BubblesSmall
 @onready var label: Label = $WaterMeterLabel
 @onready var max_sprite: Sprite2D = $Max
 @onready var power_filler: Sprite2D = $PowerFiller