Merge pull request #468 from aunyks/ray-cast-vehicle-lateral-wheel-grip

Add Ability to Control Side-to-Side Grip / Forward Grip of Raycast Vehicle Wheels

1 files changed, 14 insertions, 7 deletions

diff --git a/src/control/ray_cast_vehicle_controller.rs b/src/control/ray_cast_vehicle_controller.rs
index 42bb112..5daa435 100644
--- a/src/control/ray_cast_vehicle_controller.rs
+++ b/src/control/ray_cast_vehicle_controller.rs
@@ -37,7 +37,9 @@ pub struct WheelTuning {
     pub suspension_damping: Real,
     /// The maximum distance the suspension can travel before and after its resting length.
     pub max_suspension_travel: Real,
-    /// Parameter controlling how much traction the tire his.
+    /// The multiplier of friction between a tire and the collider it's on top of.
+    pub side_friction_stiffness: Real,
+    /// Parameter controlling how much traction the tire has.
     ///
     /// The larger the value, the more instantaneous braking will happen (with the risk of
     /// causing the vehicle to flip if it’s too strong).
@@ -53,6 +55,7 @@ impl Default for WheelTuning {
             suspension_compression: 0.83,
             suspension_damping: 0.88,
             max_suspension_travel: 5.0,
+            side_friction_stiffness: 1.0,
             friction_slip: 10.5,
             max_suspension_force: 6000.0,
         }
@@ -86,13 +89,15 @@ struct WheelDesc {
     ///
     /// Increase this value if the suspension appears to overshoot.
     pub damping_relaxation: Real,
-    /// Parameter controlling how much traction the tire his.
+    /// Parameter controlling how much traction the tire has.
     ///
     /// The larger the value, the more instantaneous braking will happen (with the risk of
     /// causing the vehicle to flip if it’s too strong).
     pub friction_slip: Real,
     /// The maximum force applied by the suspension.
     pub max_suspension_force: Real,
+    /// The multiplier of friction between a tire and the collider it's on top of.
+    pub side_friction_stiffness: Real,
 }
 
 #[derive(Copy, Clone, Debug, PartialEq)]
@@ -128,11 +133,13 @@ pub struct Wheel {
     ///
     /// Increase this value if the suspension appears to overshoot.
     pub damping_relaxation: Real,
-    /// Parameter controlling how much traction the tire his.
+    /// Parameter controlling how much traction the tire has.
     ///
     /// The larger the value, the more instantaneous braking will happen (with the risk of
     /// causing the vehicle to flip if it’s too strong).
-    friction_slip: Real,
+    pub friction_slip: Real,
+    /// The multiplier of friction between a tire and the collider it's on top of.
+    pub side_friction_stiffness: Real,
     /// The wheel’s current rotation on its axle.
     pub rotation: Real,
     delta_rotation: Real,
@@ -189,6 +196,7 @@ impl Wheel {
             skid_info: 0.0,
             side_impulse: 0.0,
             forward_impulse: 0.0,
+            side_friction_stiffness: info.side_friction_stiffness,
         }
     }
 
@@ -260,6 +268,7 @@ impl DynamicRayCastVehicleController {
             friction_slip: tuning.friction_slip,
             max_suspension_travel: tuning.max_suspension_travel,
             max_suspension_force: tuning.max_suspension_force,
+            side_friction_stiffness: tuning.side_friction_stiffness,
         };
 
         let wheel_id = self.wheels.len();
@@ -509,8 +518,6 @@ impl DynamicRayCastVehicleController {
         }
     }
 
-    const SIDE_FRICTION_STIFFNESS2: Real = 1.0;
-
     fn update_friction(&mut self, bodies: &mut RigidBodySet, colliders: &ColliderSet, dt: Real) {
         let num_wheels = self.wheels.len();
 
@@ -574,7 +581,7 @@ impl DynamicRayCastVehicleController {
                         );
                     }
 
-                    wheel.side_impulse *= Self::SIDE_FRICTION_STIFFNESS2;
+                    wheel.side_impulse *= wheel.side_friction_stiffness;
                 }
             }
         }