drag to rotate camera

scenes/Main.tscn

@@ -1,7 +1,7 @@
 [gd_scene load_steps=4 format=2]
 
-[ext_resource path="res://scenes/Train.tscn" type="PackedScene" id=1]
-[ext_resource path="res://scenes/Railway.tscn" type="PackedScene" id=2]
+[ext_resource path="res://scenes/trains/Train.tscn" type="PackedScene" id=1]
+[ext_resource path="res://scenes/trains/Railway.tscn" type="PackedScene" id=2]
 [ext_resource path="res://scenes/OrbitCamera.tscn" type="PackedScene" id=3]
 
 [node name="Main" type="Node2D"]
@@ -10,7 +10,6 @@
 transform = Transform( 0.515898, 0.606099, -0.605386, -0.393123, 0.795389, 0.461314, 0.76112, -2.26831e-08, 0.648611, 0, 0, 0 )
 
 [node name="OrbitCamera" parent="." instance=ExtResource( 3 )]
-_speed = 0.5
 
 [node name="Railway" parent="." instance=ExtResource( 2 )]
 

scenes/OrbitCamera.tscn

@@ -6,5 +6,5 @@
 script = ExtResource( 1 )
 
 [node name="Camera" type="Camera" parent="."]
-transform = Transform( 1, 0, 0, 0, 0.913325, 0.407231, 0, -0.407231, 0.913325, 0, 24.1191, 58.6188 )
+transform = Transform( 1, 0, 0, 0, 0.964146, 0.265371, 0, -0.265371, 0.964146, 0, 2.21115, 9.48434 )
 fov = 25.0

scenes/trains/Railway.tscn

@@ -1,6 +1,6 @@
 [gd_scene load_steps=3 format=2]
 
-[ext_resource path="res://scripts/Railway.cs" type="Script" id=1]
+[ext_resource path="res://scripts/trains/Railway.cs" type="Script" id=1]
 
 [sub_resource type="Curve3D" id=1]
 bake_interval = 0.01

scenes/trains/Train.tscn

@@ -1,7 +1,7 @@
 [gd_scene load_steps=3 format=2]
 
-[ext_resource path="res://scripts/Train.cs" type="Script" id=1]
-[ext_resource path="res://scenes/TrainCar.tscn" type="PackedScene" id=2]
+[ext_resource path="res://scripts/trains/Train.cs" type="Script" id=1]
+[ext_resource path="res://scenes/trains/TrainCar.tscn" type="PackedScene" id=2]
 
 [node name="Train" type="Spatial"]
 script = ExtResource( 1 )

scenes/trains/TrainCar.tscn

@@ -1,7 +1,7 @@
 [gd_scene load_steps=3 format=2]
 
-[ext_resource path="res://scripts/TrainCar.cs" type="Script" id=1]
-[ext_resource path="res://scenes/Bogie.tscn" type="PackedScene" id=2]
+[ext_resource path="res://scripts/trains/TrainCar.cs" type="Script" id=1]
+[ext_resource path="res://scenes/trains/Bogie.tscn" type="PackedScene" id=2]
 
 [node name="Train Car" type="Spatial"]
 script = ExtResource( 1 )

scripts/OrbitCamera.cs

@@ -4,15 +4,44 @@ using System;
 public class OrbitCamera : Spatial
 {
     [Export]
-    private float _speed;
+    private float _sensitivity = 200f;
 
-    public override void _Ready()
+    private Vector2 _rotation;
+    private bool _canRotate = false;
+
+    public override void _Input(InputEvent e)
     {
-
+        if (e is InputEventMouseMotion mouseMotion)
+        {
+            HandleMouseMovement(mouseMotion);
+        }
+        if (e is InputEventMouseButton mouseButton)
+        {
+            HandleMouseButton(mouseButton);
+        }
     }
 
     public override void _Process(float delta)
     {
-        Rotate(Vector3.Up, _speed * delta);
+        Rotation = Vector3.Zero;
+        var sensitivity = -1f / _sensitivity;
+        Rotate(Vector3.Right, _rotation.y * sensitivity);
+        Rotate(Vector3.Up, _rotation.x * sensitivity);
+    }
+
+    // left click to drag
+    private void HandleMouseButton(InputEventMouseButton mouseButton)
+    {
+        if (mouseButton.ButtonIndex != (int)ButtonList.Left) return;
+
+        _canRotate = mouseButton.Pressed;
+    }
+
+    private void HandleMouseMovement(InputEventMouseMotion mouseMotion)
+    {
+        if (!_canRotate) return;
+
+        var delta = mouseMotion.Relative;
+        _rotation += delta;
     }
 }