Bug Fix

Tests/Line2d.cs

@@ -0,0 +1,71 @@
+using Godot;
+using System;
+
+public partial class Line2d : Line2D
+{
+	private TestScene Test { get; set; }
+	public Vector2 Start => Test.A.Position;
+	public Vector2 End => Test.B.Position;
+	public float CurveRate { get; set; } = 20;
+	public int CDir { get; set; } = 1;
+
+	private void MakeCurve(float curveRate=20f, int cDir = 1)
+	{
+		Vector2[] xs = new Vector2[17];
+		int[] x2 = new[] { 4, 12 };
+		int[] x3 = new[] { 2, 6, 10, 14};
+		int[] x4 = new[] { 1, 3, 5, 7, 9, 11, 13, 15 };
+		Vector2 vd = End - Start;
+		Vector2 nor = vd.Rotated(Mathf.Pi / 2 * cDir);
+		Vector2 center = vd / 2 + 4f * nor / curveRate;
+		xs[0] = Start;
+		xs[16] = End;
+		xs[8] = center + xs[0];
+		foreach (int i in x2)
+		{
+			Vector2 v = xs[i + 4] - xs[i - 4];
+			Vector2 n = v.Rotated(Mathf.Pi / 2 * cDir);
+			Vector2 w = v / 2 + 2f * n / curveRate;
+			xs[i] = w + xs[i - 4];
+		}
+
+		foreach (int i in x3)
+		{
+			Vector2 v = xs[i + 2] - xs[i - 2];
+			Vector2 n = v.Rotated(Mathf.Pi / 2 * cDir);
+			Vector2 w = v / 2 + n / curveRate;
+			xs[i] = w + xs[i - 2];
+		}
+
+		foreach (int i in x4)
+		{
+			Vector2 v = xs[i + 1] - xs[i - 1];
+			Vector2 n = v.Rotated(Mathf.Pi / 2 * cDir);
+			Vector2 w = v / 2 + n / curveRate;
+			xs[i] = w + xs[i - 1];
+		}
+
+		Points = xs;
+	}
+
+	private void T()
+	{
+		Points = new[] { new Vector2(1, 1), new Vector2(2, 3) };
+		GD.Print(Points.Length);
+	}
+
+	// Called when the node enters the scene tree for the first time.
+	public override void _Ready()
+	{
+		Test = GetParent<TestScene>();
+		
+		GD.Print("Ready");
+	}
+
+	// Called every frame. 'delta' is the elapsed time since the previous frame.
+	public override void _Process(double delta)
+	{
+		//T();
+		MakeCurve(CurveRate, CDir);
+	}
+}

Tests/Test2.cs

@@ -0,0 +1,12 @@
+using Godot;
+
+public partial class Test2 : Node2D
+{
+	public override void _Ready()
+	{
+		GD.Print("READY  ddd");
+	}
+	public override void _Process(double delta)
+	{
+	}
+}

Tests/TestScene.cs

@@ -0,0 +1,37 @@
+using Godot;
+using System;
+
+public partial class TestScene : Node2D
+{
+	public Marker2D A { get; set; }
+	public Marker2D B { get; set; }
+
+	public Line2d L1 { get; set; }
+
+	public Line2d L2 { get; set; }
+	public Line2d L3 { get; set; }
+	public Line2d L4 { get; set; }
+	// Called when the node enters the scene tree for the first time.
+	public override void _Ready()
+	{
+		A = GetNode<Marker2D>("A");
+		B = GetNode<Marker2D>("B");
+		L1 = GetNode<Line2d>("L1");
+		L2 = GetNode<Line2d>("L2");
+		L3 = GetNode<Line2d>("L3");
+		L4 = GetNode<Line2d>("L4");
+		L1.CurveRate = 20;
+		L1.CDir = 1;
+		L2.CurveRate = 10;
+		L1.CDir = 1;
+		L3.CurveRate = 10;
+		L3.CDir = -1;
+		L4.CurveRate = 20;
+		L4.CDir = -1;
+	}
+
+	// Called every frame. 'delta' is the elapsed time since the previous frame.
+	public override void _Process(double delta)
+	{
+	}
+}