Make camera smoothly follow player

player/CameraController.cs

@@ -1,7 +1,8 @@
 public partial class CameraController : SpringArm3D
 {
 	[Export] public Vector2 MouseSensitivity { get; set; } = new(0.2f, 0.2f); // Degrees per pixel.
-	[Export] public float PitchMinimum { get; set; } = -90;
+	[Export] public float MovementSmoothing { get; set; } = 8.0f;
+	[Export] public float PitchMinimum { get; set; } = -85;
 	[Export] public float PitchMaximum { get; set; } = -25;
 
 	// FIXME: Fix the "snappyness" when moving slowly.
@@ -12,6 +13,15 @@ public partial class CameraController : SpringArm3D
 	public static bool IsMouseCaptured
 		=> Input.MouseMode == Input.MouseModeEnum.Captured;
 
+	Vector3 _offset;
+	Node3D _player;
+	public override void _Ready()
+	{
+		_offset = Position;
+		_player = this.GetParentOrThrow<Node3D>();
+		Transform = _player.GlobalTransform.Translated(_offset);
+	}
+
 	public override void _Input(InputEvent ev)
 	{
 		if (IsMouseCaptured && ev.IsActionPressed("ui_cancel")) {
@@ -44,4 +54,9 @@ public partial class CameraController : SpringArm3D
 		pitch = Clamp(pitch, DegToRad(PitchMinimum), DegToRad(PitchMaximum));
 		Rotation = new(pitch, yaw, 0);
 	}
+
+	public override void _Process(double delta)
+	{
+		Position = Position.Damp(_offset + _player.GlobalPosition, MovementSmoothing, delta);
+	}
 }

player/character.tscn

@@ -32,6 +32,7 @@ script = ExtResource("1_akh08")
 
 [node name="CameraArm" type="SpringArm3D" parent="."]
 transform = Transform3D(1, 0, 0, 0, 0.766044, 0.642788, 0, -0.642788, 0.766044, 0, 0.1, 0)
+top_level = true
 collision_mask = 3
 spring_length = 2.0
 margin = 0.05

terrain/Terrain+Editing.cs

@@ -1,5 +1,4 @@
 using System.IO;
-using System.Runtime.InteropServices;
 
 public partial class Terrain
 {

terrain/TerrainChunk.cs

@@ -15,6 +15,12 @@ public partial class TerrainChunk
 
 	[Export] public byte[] Data { get; set; } = new byte[SizeInBytes];
 
+	public bool IsEmpty { get {
+		foreach (var b in Data)
+			if (b != 0) return false;
+		return true;
+	} }
+
 	public ref Tile this[TilePos pos] { get {
 		var tiles = MemoryMarshal.Cast<byte, Tile>(Data);
 		return ref tiles[GetIndex(pos)];

utility/GodotExtensions.cs

@@ -1,7 +1,23 @@
 public static class GodotExtensions
 {
-	public static Vector2I RoundToVector2I(this Vector2 vector)
-		=> new(RoundToInt(vector.X), RoundToInt(vector.Y));
+	public static T GetParentOrThrow<T>(this Node node)
+		where T : class
+	{
+		var parent = node.GetParent();
+		if (parent == null) throw new InvalidOperationException($"Parent of {node} is null");
+		if (parent is not T result) throw new InvalidCastException($"Parent of {node} is {node.GetType()}, not {typeof(T)}");
+		return result;
+	}
+
+	public static T GetNodeOrThrow<T>(this Node parent, NodePath path)
+		where T : class
+	{
+		var node = parent.GetNodeOrNull(path);
+		if (node == null) throw new InvalidOperationException($"Could not find node {path} from {parent}");
+		if (node is not T result) throw new InvalidCastException($"Node {path} from {parent} is {node.GetType()}, not {typeof(T)}");
+		return result;
+	}
+
 
 	public static (Corner, Corner) GetCorners(this Side side)
 		=> side switch {

utility/MathExtensions.cs

@@ -0,0 +1,12 @@
+public static class MathExtensions
+{
+	// Framerate independent dampening functions, similar to lerp.
+	// https://rorydriscoll.com/2016/03/07/frame-rate-independent-damping-using-lerp/
+	public static float Damp(this float from, float to, float lambda, double delta)
+		=> Lerp(from, to, 1 - Exp(-lambda * (float)delta));
+	public static Vector3 Damp(this Vector3 from, Vector3 to, float lambda, double delta)
+		=> from.Lerp(to, 1 - Exp(-lambda * (float)delta));
+
+	public static Vector2I RoundToVector2I(this Vector2 vector)
+		=> new(RoundToInt(vector.X), RoundToInt(vector.Y));
+}