Implement our own spring-arm-like functionality

player/CameraController.cs

@@ -1,28 +1,29 @@
-public partial class CameraController : SpringArm3D
+public partial class CameraController : Camera3D
 {
-	[Export] public float MovementSmoothing { get; set; } = 8.0f;
+	[ExportCategory("Follow")]
+	[Export] public float FollowDistance  { get; set; } = 1.2f;
+	[Export] public float FollowYOffset   { get; set; } = 1.0f;
+	[Export] public float FollowSmoothing { get; set; } = 12.0f;
 
+	[ExportCategory("Rotation")]
 	[Export] public Vector2 MouseSensitivity { get; set; } = new(0.2f, 0.2f); // Degrees per pixel.
-
+	[Export] public float PitchMinimum   { get; set; } = 20;
-	[Export] public float PitchMinimum { get; set; } = 30;
 	[Export] public float PitchMaximum   { get; set; } = 65;
 	[Export] public float PitchSmoothing { get; set; } = 12.0f;
 
-	// FIXME: Fix the "snappyness" when moving slowly.
-	// FIXME: Fix spring arm clipping through terrain and similar.
 	// TODO: Gradually return to maximum spring length.
 	// TODO: Turn player transparent as the camera moves closer.
 
 	public static bool IsMouseCaptured
 		=> Input.MouseMode == Input.MouseModeEnum.Captured;
 
-	Vector3 _offset;
 	Node3D _player;
+	Vector3 _smoothPlayerPos;
 	public override void _Ready()
 	{
-		_offset = Position;
 		_player = this.GetParentOrThrow<Node3D>();
-		Transform = _player.GlobalTransform.Translated(_offset);
+		_smoothPlayerPos = _player.GlobalPosition;
+		Transform = _player.GlobalTransform.Translated(new(0.0f, FollowYOffset, 0.0f));
 	}
 
 	public override void _Input(InputEvent ev)
@@ -56,10 +57,35 @@ public partial class CameraController : SpringArm3D
 		RotationDegrees = new(pitch, yaw, 0);
 	}
 
-	public override void _Process(double delta)
+	public override void _PhysicsProcess(double delta)
 	{
-		Position = Position.Damp(_offset + _player.GlobalPosition, MovementSmoothing, delta);
+		_smoothPlayerPos = _smoothPlayerPos.Damp(_player.GlobalPosition, FollowSmoothing, delta);
+
+		var target = _smoothPlayerPos
+		           + Basis.Z    * FollowDistance
+		           + Vector3.Up * FollowYOffset;
 
+		Position   = OffsetRayIntersection(_smoothPlayerPos, target, 0.2f);
+	}
+
+	Vector3 OffsetRayIntersection(Vector3 from, Vector3 to, float margin)
+	{
+		const PhysicsLayer CollisionMask = PhysicsLayer.Terrain
+		                                 | PhysicsLayer.Objects;
+		var query = PhysicsRayQueryParameters3D.Create(from, to, (uint)CollisionMask);
+		var result = GetWorld3D().DirectSpaceState.IntersectRay(query);
+		if (result.Count > 0) {
+			var hit = (Vector3)result["position"];
+			var safeDistance = Max(0, from.DistanceTo(hit) - margin);
+			return from + (to - from).Normalized() * safeDistance;
+		} else {
+			// No intersection occured,
+			return to;
+		}
+	}
+
+	public override void _Process(double delta)
+	{
 		var pitch = RotationDegrees.X;
 		var (min, max) = (-PitchMaximum, -PitchMinimum);
 		if (pitch < min) pitch = pitch.Damp(min, PitchSmoothing, delta);

player/character.tscn

@@ -20,26 +20,18 @@ collision_mask = 3
 floor_max_angle = 0.698132
 
 [node name="MeshInstance3D" type="MeshInstance3D" parent="."]
-transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0.15, 0)
 mesh = SubResource("SphereMesh_7ljg8")
 
 [node name="CollisionShape3D" type="CollisionShape3D" parent="."]
-transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0.2, 0)
+transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0.05, 0)
 shape = SubResource("SphereShape3D_6qbb2")
 
-[node name="MovementController" type="Node" parent="."]
+[node name="Camera" type="Camera3D" parent="."]
-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
-script = ExtResource("2_2din1")
-
-[node name="Camera" type="Camera3D" parent="CameraArm"]
-transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 2)
 current = true
 size = 4.5
 far = 500.0
+script = ExtResource("2_2din1")
+
+[node name="MovementController" type="Node" parent="."]
+script = ExtResource("1_akh08")