//-------------------------------------------------------------- #region Creation & Cleanup //-------------------------------------------------------------- public VehicleObject(IServiceLocator services) { _services = services; Name = "Vehicle"; _inputService = _services.GetInstance<IInputService>(); _simulation = _services.GetInstance<Simulation>(); // Load models for rendering. var contentManager = _services.GetInstance<ContentManager>(); _vehicleModelNode = contentManager.Load<ModelNode>("Car/Car").Clone(); _wheelModelNodes = new ModelNode[4]; _wheelModelNodes[0] = contentManager.Load<ModelNode>("Car/Wheel").Clone(); _wheelModelNodes[1] = _wheelModelNodes[0].Clone(); _wheelModelNodes[2] = _wheelModelNodes[0].Clone(); _wheelModelNodes[3] = _wheelModelNodes[0].Clone(); // Add wheels under the car model node. _vehicleModelNode.Children.Add(_wheelModelNodes[0]); _vehicleModelNode.Children.Add(_wheelModelNodes[1]); _vehicleModelNode.Children.Add(_wheelModelNodes[2]); _vehicleModelNode.Children.Add(_wheelModelNodes[3]); // ----- Create the chassis of the car. // The Vehicle needs a rigid body that represents the chassis. This can be any shape (e.g. // a simple BoxShape). In this example we will build a convex polyhedron from the car model. // 1. Extract the vertices from the car model. // The car model has ~10,000 vertices. It consists of a MeshNode for the glass // parts and a MeshNode "Car" for the chassis. var meshNode = _vehicleModelNode.GetDescendants() .OfType<MeshNode>() .First(mn => mn.Name == "Car"); var mesh = MeshHelper.ToTriangleMesh(meshNode.Mesh); // Apply the transformation of the mesh node. mesh.Transform(meshNode.PoseWorld * Matrix44F.CreateScale(meshNode.ScaleWorld)); // 2. (Optional) Create simplified convex hull from mesh. // We could also skip this step and directly create a convex polyhedron from the mesh using // var chassisShape = new ConvexPolyhedron(mesh.Vertices); // However, the convex polyhedron would still have 500-600 vertices. // We can reduce the number of vertices by using the GeometryHelper. // Create a convex hull for mesh with max. 64 vertices. Additional, shrink the hull by 4 cm. var convexHull = GeometryHelper.CreateConvexHull(mesh.Vertices, 64, -0.04f); // 3. Create convex polyhedron shape using the vertices of the convex hull. var chassisShape = new ConvexPolyhedron(convexHull.Vertices.Select(v => v.Position)); // (Note: Building convex hulls and convex polyhedra are time-consuming. To save loading time // we should build the shape in the XNA content pipeline. See other DigitalRune Physics // Samples.) // The mass properties of the car. We use a mass of 800 kg. var mass = MassFrame.FromShapeAndMass(chassisShape, Vector3F.One, 800, 0.1f, 1); // Trick: We artificially modify the center of mass of the rigid body. Lowering the center // of mass makes the car more stable against rolling in tight curves. // We could also modify mass.Inertia for other effects. var pose = mass.Pose; pose.Position.Y -= 0.5f; // Lower the center of mass. pose.Position.Z = -0.5f; // The center should be below the driver. // (Note: The car model is not exactly centered.) mass.Pose = pose; // Material for the chassis. var material = new UniformMaterial { Restitution = 0.1f, StaticFriction = 0.2f, DynamicFriction = 0.2f }; var chassis = new RigidBody(chassisShape, mass, material) { Pose = new Pose(new Vector3F(0, 2, 0)), // Start position UserData = "NoDraw", // (Remove this line to render the collision model.) }; // ----- Create the vehicle. Vehicle = new Vehicle(_simulation, chassis); // Add 4 wheels. Vehicle.Wheels.Add(new Wheel { Offset = new Vector3F(-0.9f, 0.6f, -2.0f), Radius = 0.36f, SuspensionRestLength = 0.55f, MinSuspensionLength = 0.25f, Friction = 2 }); // Front left Vehicle.Wheels.Add(new Wheel { Offset = new Vector3F(0.9f, 0.6f, -2.0f), Radius = 0.36f, SuspensionRestLength = 0.55f, MinSuspensionLength = 0.25f, Friction = 2 }); // Front right Vehicle.Wheels.Add(new Wheel { Offset = new Vector3F(-0.9f, 0.6f, 0.98f), Radius = 0.36f, SuspensionRestLength = 0.55f, MinSuspensionLength = 0.25f, Friction = 1.8f });// Back left Vehicle.Wheels.Add(new Wheel { Offset = new Vector3F(0.9f, 0.6f, 0.98f), Radius = 0.36f, SuspensionRestLength = 0.55f, MinSuspensionLength = 0.25f, Friction = 1.8f }); // Back right // Vehicles are disabled per default. This way we can create the vehicle and the simulation // objects are only added when needed. Vehicle.Enabled = false; }
//-------------------------------------------------------------- /// <summary> /// Initializes a new instance of the <see cref="VehicleForceEffect"/> class. /// </summary> /// <param name="vehicle">The vehicle.</param> internal VehicleForceEffect(Vehicle vehicle) { Debug.Assert(vehicle != null); Vehicle = vehicle; }