From 52cac4a3eba5b948d8358adab0304a234c902ac9 Mon Sep 17 00:00:00 2001
From: Joe Ardent <code@ardent.nebcorp.com>
Date: Thu, 1 May 2025 15:45:12 -0700
Subject: [PATCH] tweak; apply suspension force at contact point, not caster
 origin

---
 src/bike.rs    | 31 +++++++++++++++----------------
 src/physics.rs | 32 ++++++++++++++------------------
 2 files changed, 29 insertions(+), 34 deletions(-)

diff --git a/src/bike.rs b/src/bike.rs
index 0e8a4d8..4e819e5 100644
--- a/src/bike.rs
+++ b/src/bike.rs
@@ -92,6 +92,19 @@ fn spawn_bike(
     let body_collider =
         Collider::capsule_endpoints(0.5, Vec3::new(0.0, 0.0, -0.65), Vec3::new(0.0, 0.0, 0.8));
 
+    let pbr_bundle = {
+        let color = Color::srgb(0.7, 0.05, 0.7);
+        let mut xform = Transform::default();
+        xform.rotate_x(FRAC_PI_2);
+        (
+            Mesh3d(meshes.add(Capsule3d::new(0.5, 1.45))),
+            xform,
+            Visibility::Visible,
+            MeshMaterial3d(materials.add(color)),
+            TransformInterpolation,
+        )
+    };
+
     let mut body = commands.spawn((xform, Visibility::default()));
     body.insert((
         Name::new("body"),
@@ -108,25 +121,12 @@ fn spawn_bike(
         ExternalTorque::ZERO.with_persistence(false),
     ));
 
-    let pbr_bundle = {
-        let color = Color::srgb(0.7, 0.05, 0.7);
-        let mut xform = Transform::default();
-        xform.rotate_x(FRAC_PI_2);
-        (
-            Mesh3d(meshes.add(Capsule3d::new(0.5, 1.45))),
-            xform,
-            Visibility::Visible,
-            MeshMaterial3d(materials.add(color)),
-            TransformInterpolation,
-        )
-    };
-    let parent = body.id();
-    body.insert(spawn_children(parent, pbr_bundle, meshes, materials));
+    body.insert(spawn_children(body.id(), meshes, materials))
+        .with_child(pbr_bundle);
 }
 
 fn spawn_children(
     parent: Entity,
-    body: impl Bundle,
     mut meshes: ResMut<Assets<Mesh>>,
     mut materials: ResMut<Assets<StandardMaterial>>,
 ) -> impl Bundle {
@@ -147,7 +147,6 @@ fn spawn_children(
     let rear_wheel_pos = REAR_ATTACH + (rear_rake * REST_DISTANCE);
 
     children![
-        body,
         (
             RayCaster::new(FRONT_ATTACH, Dir3::new_unchecked(front_rake))
                 .with_max_hits(1)
diff --git a/src/physics.rs b/src/physics.rs
index f75c372..c26b8b8 100644
--- a/src/physics.rs
+++ b/src/physics.rs
@@ -20,9 +20,9 @@ pub struct CatControllerSettings {
 impl Default for CatControllerSettings {
     fn default() -> Self {
         Self {
-            kp: 55.0,
-            kd: 20.0,
-            ki: 12.5,
+            kp: 60.0,
+            kd: 30.0,
+            ki: 0.0,
         }
     }
 }
@@ -260,11 +260,7 @@ mod systems {
                     hit_point + force,
                     Color::linear_rgb(1., 0.5, 0.2),
                 );
-                bike_forces.apply_force_at_point(
-                    force,
-                    caster.global_origin(),
-                    bike_xform.translation + com.0,
-                );
+                bike_forces.apply_force_at_point(force, hit_point, bike_xform.translation + com.0);
             } else {
                 xform.translation = config.attach + (caster.direction.as_vec3() * config.rest_dist);
                 state.reset();
@@ -272,7 +268,7 @@ mod systems {
         }
     }
 
-    pub(super) fn steering(
+    pub(super) fn wheel_action(
         bike_query: Single<
             (
                 &Transform,
@@ -291,7 +287,7 @@ mod systems {
         let bike_vel = bike_vel.0;
 
         let dt = time.delta().as_secs_f32();
-        let max_thrust = 1000.0;
+        let max_thrust = 500.0;
         let yaw_angle = -yaw_to_angle(input.yaw);
 
         for (mut state, config, wheel) in wheels.iter_mut() {
@@ -304,8 +300,8 @@ mod systems {
                 let forward = normal.cross(*bike_xform.right());
                 let thrust_mag = input.throttle * max_thrust * dt;
                 let (thrust_dir, thrust_force) = match wheel {
-                    CyberWheel::Rear => (forward, thrust_mag * 0.5),
-                    CyberWheel::Front => (rot * forward, thrust_mag),
+                    CyberWheel::Rear => (forward, thrust_mag),
+                    CyberWheel::Front => (rot * forward, thrust_mag * 0.1),
                 };
 
                 let thrust = thrust_force * thrust_dir;
@@ -368,11 +364,11 @@ mod systems {
 
         let dt = time.delta_secs();
 
-        let speed = vel.length();
-        let dspeed = speed.powf(1.2) * 0.01;
+        let speed = vel.length_squared();
+        let dspeed = speed * 0.0000001;
         let dir = vel.normalize_or_zero();
         let drag = -dspeed * dt * DRAG_COEFF * dir;
-        if speed > 1.0 {
+        if speed > 0.1 {
             force.apply_force_at_point(
                 drag,
                 xform.translation - (0.2 * *xform.down()),
@@ -380,7 +376,7 @@ mod systems {
             );
         }
 
-        bevy::log::debug!("speed: {}, drag force: {}", speed, drag.length());
+        bevy::log::debug!("speed: {}, drag force: {}", vel.length(), drag.length());
 
         gizmos.arrow(
             xform.translation,
@@ -427,7 +423,7 @@ mod systems {
     }
 }
 
-use systems::{apply_lean, calculate_lean, drag, steering, suspension, tweak};
+use systems::{apply_lean, calculate_lean, drag, suspension, tweak, wheel_action};
 
 pub struct CyberPhysicsPlugin;
 
@@ -442,7 +438,7 @@ impl Plugin for CyberPhysicsPlugin {
             })
             .add_systems(
                 FixedUpdate,
-                (calculate_lean, apply_lean, suspension, steering, drag).chain(),
+                (calculate_lean, apply_lean, suspension, wheel_action, drag).chain(),
             )
             .add_systems(Update, tweak);
     }