kinda working friction sim

src/action/systems.rs

@@ -176,16 +176,40 @@ pub(super) fn wheel_forces(
                 // do steering's share
                 if steering.is_some() {
                     let thrust = norm.cross(xform.back().into());
-                    force += yaw * thrust;
+                    force += 5.0 * yaw * thrust;
                 }
 
+                let forward = if steering.is_some() {
+                    let angle = yaw_to_angle(yaw);
+                    let rot = Quat::from_axis_angle(Vec3::Y, angle);
+                    Transform::from_rotation(rot).forward()
+                } else {
+                    xform.forward()
+                };
+
                 // do the friction's share
+                //
+                // first the brakes
                 if input.brake {
                     friction.coefficient = 2.0;
                 } else {
                     friction.coefficient = 0.0;
                 }
 
+                // now static simulated friction
+
+                let alignment = forward.dot(velocity.linvel);
+                let alignment = if alignment.is_normal() || alignment == 0.0 {
+                    alignment
+                } else {
+                    1.0
+                };
+                dbg!(alignment);
+                let sign = alignment.signum();
+                let slide = sign * (1.0 - alignment.abs());
+                let perp = forward.cross(norm).normalize();
+                force += slide * perp;
+
                 // show the force
                 #[cfg(feature = "inspector")]
                 gizmos.arrow(pos, pos + force, Color::RED);