private static void UpdateWheelVelocity(float deltaTime, ConstraintVehicle vehicle, ConstraintWheel wheel)
{
if (wheel.Tag == 1)
{
wheel.Tag = 0;
if (Numeric.IsZero(wheel.BrakeForce))
{
// We set the angular velocity, so that the wheel matches the moving underground.
Vector3 relativeContactVelocity = vehicle.Chassis.GetVelocityOfWorldPoint(wheel.GroundPosition)
- wheel.TouchedBody.GetVelocityOfWorldPoint(wheel.GroundPosition);
float forwardVelocity = Vector3.Dot(relativeContactVelocity, wheel.GroundForward);
wheel.AngularVelocity = forwardVelocity / wheel.Radius;
wheel.RotationAngle += wheel.AngularVelocity * deltaTime;
}
else
{
// Braking wheels do not rotate.
wheel.AngularVelocity = 0;
}
}
else
{
// To keep it simple: The wheel continues spinning in the same direction.
// Damp angular velocity and update rotation angle.
wheel.AngularVelocity *= 0.99f;
wheel.RotationAngle += wheel.AngularVelocity * deltaTime;
}
}
// Creates or gets the ConstraintVehicleHandler instance and adds a vehicle.
internal static void Add(ConstraintVehicle vehicle)
{
var simulation = vehicle.Simulation;
var handler = GetHandler(simulation);
if (handler == null)
{
// The first vehicle: Add a new instance of this class to the simulation.
handler = new ConstraintVehicleHandler();
simulation.ForceEffects.Add(handler);
simulation.SubTimeStepFinished += handler.OnSubTimeStepFinished;
}
handler._vehicles.Add(vehicle);
}
// Removes a vehicle. When the last vehicle is removed, the ConstraintVehicleHandler
// instance is removed too.
internal static void Remove(ConstraintVehicle vehicle)
{
Simulation simulation = vehicle.Simulation;
ConstraintVehicleHandler handler = GetHandler(simulation);
if (handler != null)
{
handler._vehicles.Remove(vehicle);
// The last vehicle was removed.
if (handler._vehicles.Count == 0)
{
simulation.ForceEffects.Remove(handler);
simulation.SubTimeStepFinished -= handler.OnSubTimeStepFinished;
}
}
}
