add mass to wheels

src/bike.rs

@@ -226,6 +226,9 @@ fn wheel_mesh(
         Mesh3d(meshes.add(tire_mesh)),
         MeshMaterial3d(materials.add(wheel_material.clone())),
         xform,
+        Collider::sphere(WHEEL_RADIUS),
+        ColliderDensity(0.5),
+        CollisionLayers::NONE,
         TransformInterpolation,
         wheel,
     ));

src/physics.rs

@@ -1,7 +1,7 @@
 use avian3d::{math::Scalar, prelude::*};
 use bevy::prelude::*;
 
-const DRAG_COEFF: Scalar = 0.1;
+const DRAG_COEFF: Scalar = 0.00001;
 
 #[derive(Resource, Default, Debug, Reflect)]
 #[reflect(Resource)]
@@ -20,9 +20,9 @@ pub struct CatControllerSettings {
 impl Default for CatControllerSettings {
     fn default() -> Self {
         Self {
-            kp: 16.0,
-            kd: 2.0,
-            ki: 0.9,
+            kp: 45.0,
+            kd: 15.0,
+            ki: 1.0,
         }
     }
 }
@@ -272,7 +272,7 @@ mod systems {
         let bike_vel = bike_vel.0;
 
         let dt = time.delta().as_secs_f32();
-        let max_thrust = 2000.0;
+        let max_thrust = 5000.0;
         let yaw_angle = -yaw_to_angle(input.yaw);
 
         for (mut state, config, wheel) in wheels.iter_mut() {
@@ -345,7 +345,11 @@ mod systems {
         let dir = vel.normalize_or_zero();
         let drag = -dspeed * dt * DRAG_COEFF * dir;
         if speed > 1.0 {
-            force.apply_force_at_point(drag, xform.translation, xform.translation);
+            force.apply_force_at_point(
+                drag,
+                xform.translation - (0.25 * *xform.down()),
+                xform.translation,
+            );
         }
 
         bevy::log::debug!("speed: {}, drag force: {}", speed, drag.length());