many small changes, and few big ones

reusable/conveyor/conveyor.gd

@@ -0,0 +1,62 @@
+@tool
+class_name Conveyor extends Node2D
+
+const GAP = 8.0
+const SPEED = 0.0041 # ~ the targeted physics tick time
+
+@export var conveyor_segments: int = 20:
+	set(v):
+		conveyor_segments = v
+		create_segments()
+	get:
+		return conveyor_segments
+
+@export var speed_mult: float = 20.0
+
+var conveyor_seg_scn = preload("uid://be7ki66sskav5")
+var segments_top: Array[Node2D] = []
+var segments_bottom: Array[Node2D] = []
+
+func create_segments():
+	for c in self.get_children():
+		c.call_deferred("queue_free")
+	segments_top = []
+	segments_bottom = []
+	# top
+	for i in range(0, conveyor_segments + 1):
+		var c = conveyor_seg_scn.instantiate()
+		c.position.x = i*8.0
+		self.segments_top.append(c)
+		self.add_child(c)
+	# bottom
+	for i in range(0, conveyor_segments + 1):
+		var c = conveyor_seg_scn.instantiate()
+		c.position.x = i*8.0
+		c.position.y = 5.0
+		self.segments_bottom.append(c)
+		self.add_child(c)
+
+func _ready() -> void:
+	create_segments()
+
+func _process(_delta: float) -> void:
+	if Engine.is_editor_hint():
+		return
+	# make it NOT framerate-depedent bc this would fuck up the positioning over time
+	var s = sign(speed_mult)
+	for p in segments_top:
+		if s > 0.0:
+			if p.position.x > conveyor_segments * GAP:
+				p.position.x = 0.0
+		else:
+			if p.position.x < 0.0:
+				p.position.x = conveyor_segments * GAP
+		p.position.x += SPEED * speed_mult
+	for p in segments_bottom:
+		if s > 0.0:
+			if p.position.x < 0.0:
+				p.position.x = conveyor_segments * GAP
+		else:
+			if p.position.x > conveyor_segments * GAP:
+				p.position.x = 0.0
+		p.position.x -= SPEED * speed_mult

reusable/conveyor/conveyor_segment.tscn

@@ -0,0 +1,10 @@
+[gd_scene load_steps=2 format=3 uid="uid://be7ki66sskav5"]
+
+[ext_resource type="Script" path="res://core/polygon/polygon.gd" id="2_hf2op"]
+
+[node name="ConveyorPart" type="AnimatableBody2D"]
+sync_to_physics = false
+
+[node name="P" type="CollisionPolygon2D" parent="."]
+polygon = PackedVector2Array(-3, -4, -3, -0.1, 3, -0.1, 3, -4)
+script = ExtResource("2_hf2op")