Add free orbit camera control

src/renderer/control.rs

@@ -10,6 +10,10 @@ mod orbit_control;
 #[doc(inline)]
 pub use orbit_control::*;
 
+mod free_orbit_control;
+#[doc(inline)]
+pub use free_orbit_control::*;
+
 mod first_person_control;
 #[doc(inline)]
 pub use first_person_control::*;

src/renderer/control/free_orbit_control.rs

@@ -0,0 +1,44 @@
+use crate::renderer::*;
+
+///
+/// A control that makes the camera orbit around a target, with no fixed up direction.
+///
+pub struct FreeOrbitControl {
+    control: CameraControl,
+}
+
+impl FreeOrbitControl {
+    /// Creates a new free orbit control with the given target and minimum and maximum distance to the target.
+    pub fn new(target: Vec3, min_distance: f32, max_distance: f32) -> Self {
+        Self {
+            control: CameraControl {
+                left_drag_horizontal: CameraAction::FreeOrbitLeft { target, speed: 0.1 },
+                left_drag_vertical: CameraAction::FreeOrbitUp { target, speed: 0.1 },
+                scroll_vertical: CameraAction::Zoom {
+                    min: min_distance,
+                    max: max_distance,
+                    speed: 0.1,
+                    target,
+                },
+                ..Default::default()
+            },
+        }
+    }
+
+    /// Handles the events. Must be called each frame.
+    pub fn handle_events(&mut self, camera: &mut Camera, events: &mut [Event]) -> bool {
+        if let CameraAction::Zoom { speed, target, .. } = &mut self.control.scroll_vertical {
+            let x = target.distance(*camera.position());
+            *speed = 0.01 * x + 0.001;
+        }
+        if let CameraAction::FreeOrbitLeft { speed, target } = &mut self.control.left_drag_horizontal {
+            let x = target.distance(*camera.position());
+            *speed = 0.01 * x + 0.001;
+        }
+        if let CameraAction::FreeOrbitUp { speed, target } = &mut self.control.left_drag_vertical {
+            let x = target.distance(*camera.position());
+            *speed = 0.01 * x + 0.001;
+        }
+        self.control.handle_events(camera, events)
+    }
+}