Tnua and dolly (#2)

* character controller + camera rig
* make tnua work
* cash collect

src/camera.rs

@@ -0,0 +1,38 @@
+use bevy::prelude::*;
+use bevy_dolly::prelude::*;
+
+impl GameCameraRig {
+    pub fn new_with_arm(arm: Vec3) -> Self {
+        Self(
+            CameraRig::builder()
+                .with(Position::new(Vec3::ZERO))
+                .with(Rotation::new(Quat::IDENTITY))
+                .with(Smooth::new_position(1.25).predictive(true))
+                .with(Smooth::new_rotation(10.))
+                .with(Arm::new(arm))
+                .with(
+                    LookAt::new(Vec3::ZERO + Vec3::Y)
+                        .tracking_smoothness(1.25)
+                        .tracking_predictive(true),
+                )
+                .build(),
+        )
+    }
+
+    pub fn set_position_target(&mut self, target_position: Vec3, target_rotation: Quat) {
+        self.driver_mut::<Position>().position = target_position;
+        self.driver_mut::<Rotation>().rotation = target_rotation;
+        self.driver_mut::<LookAt>().target = target_position + Vec3::Y;
+    }
+}
+
+/// A custom camera rig which combines smoothed movement with a look-at driver.
+#[derive(Component, Debug, Deref, DerefMut)]
+pub struct GameCameraRig(CameraRig);
+
+// Turn the nested rig into a driver, so it can be used in another rig.
+impl RigDriver for GameCameraRig {
+    fn update(&mut self, params: RigUpdateParams) -> Transform {
+        self.0.update(params.delta_time_seconds)
+    }
+}