/// <summary>
/// Constructs a new demo.
/// </summary>
/// <param name="game">Game owning this demo.</param>
public SuspensionCarDemo2(DemosGame game)
: base(game)
{
game.Camera.Position = new Vector3(0, 2, 15);
Space.Add(new Box(new Vector3(0, -5, 0), 20, 1, 20));
var body = new Box(new Vector3(0, 0, 0), 2, .5f, 3, 20);
body.CollisionInformation.LocalPosition = new Vector3(0, 1f, 0);
Space.Add(body);
AddBackWheel(new Vector3(-1f, .55f, 1.3f), body, true);
AddBackWheel(new Vector3(1f, .55f, 1.3f), body, false);
Box suspensionLeg1, suspensionLeg2;
AddDriveWheel(new Vector3(-1f, .55f, -1.3f), body, true, out drivingMotor1, out steeringMotor1, out suspensionLeg1);
AddDriveWheel(new Vector3(1f, .55f, -1.3f), body, false, out drivingMotor2, out steeringMotor2, out suspensionLeg2);
//Add a stabilizer so that the wheels can't point different directions.
var steeringStabilizer = new RevoluteAngularJoint(suspensionLeg1, suspensionLeg2, Vector3.Right);
Space.Add(steeringStabilizer);
//x and y, in terms of heightmaps, refer to their local x and y coordinates. In world space, they correspond to x and z.
//Setup the heights of the terrain.
int xLength = 180;
int zLength = 180;
float xSpacing = 8f;
float zSpacing = 8f;
var heights = new float[xLength, zLength];
for (int i = 0; i < xLength; i++)
{
for (int j = 0; j < zLength; j++)
{
float x = i - xLength / 2;
float z = j - zLength / 2;
//heights[i,j] = (float)(x * y / 1000f);
heights[i, j] = (float)(10 * (Math.Sin(x / 8) + Math.Sin(z / 8)));
//heights[i,j] = 3 * (float)Math.Sin(x * y / 100f);
//heights[i,j] = (x * x * x * y - y * y * y * x) / 1000f;
}
}
//Create the terrain.
var terrain = new Terrain(heights, new AffineTransform(
new Vector3(xSpacing, 1, zSpacing),
Quaternion.Identity,
new Vector3(-xLength * xSpacing / 2, -10, -zLength * zSpacing / 2)));
//terrain.Thickness = 5; //Uncomment this and shoot some things at the bottom of the terrain! They'll be sucked up through the ground.
Space.Add(terrain);
game.ModelDrawer.Add(terrain);
}
/// <summary>
/// Constructs a new constraint which restricts two degrees of linear freedom and two degrees of angular freedom between two entities.
/// This constructs the internal constraints, but does not configure them. Before using a constraint constructed in this manner,
/// ensure that its active constituent constraints are properly configured. The entire group as well as all internal constraints are initially inactive (IsActive = false).
/// </summary>
public LineSliderJoint()
{
IsActive = false;
PointOnLineJoint = new PointOnLineJoint();
AngularJoint = new RevoluteAngularJoint();
Limit = new LinearAxisLimit();
Motor = new LinearAxisMotor();
Add(PointOnLineJoint);
Add(AngularJoint);
Add(Limit);
Add(Motor);
}
/// <summary>
/// Constructs a new constraint which restricts three degrees of linear freedom and two degrees of angular freedom between two entities.
/// This constructs the internal constraints, but does not configure them. Before using a constraint constructed in this manner,
/// ensure that its active constituent constraints are properly configured. The entire group as well as all internal constraints are initially inactive (IsActive = false).
/// </summary>
public RevoluteJoint()
{
IsActive = false;
BallSocketJoint = new BallSocketJoint();
AngularJoint = new RevoluteAngularJoint();
Limit = new RevoluteLimit();
Motor = new RevoluteMotor();
Add(BallSocketJoint);
Add(AngularJoint);
Add(Limit);
Add(Motor);
}
/// <summary>
/// Constructs a new constraint which restricts three degrees of linear freedom and two degrees of angular freedom between two entities.
/// </summary>
/// <param name="connectionA">First entity of the constraint pair.</param>
/// <param name="connectionB">Second entity of the constraint pair.</param>
/// <param name="anchor">Point around which both entities rotate.</param>
/// <param name="freeAxis">Axis around which the hinge can rotate.</param>
public RevoluteJoint(Entity connectionA, Entity connectionB, Vector3 anchor, Vector3 freeAxis)
{
if (connectionA == null)
connectionA = TwoEntityConstraint.WorldEntity;
if (connectionB == null)
connectionB = TwoEntityConstraint.WorldEntity;
BallSocketJoint = new BallSocketJoint(connectionA, connectionB, anchor);
AngularJoint = new RevoluteAngularJoint(connectionA, connectionB, freeAxis);
Limit = new RevoluteLimit(connectionA, connectionB);
Motor = new RevoluteMotor(connectionA, connectionB, freeAxis);
Limit.IsActive = false;
Motor.IsActive = false;
//Ensure that the base and test direction is perpendicular to the free axis.
Vector3 baseAxis = anchor - connectionA.position;
if (baseAxis.LengthSquared() < Toolbox.BigEpsilon) //anchor and connection a in same spot, so try the other way.
baseAxis = connectionB.position - anchor;
baseAxis -= Vector3.Dot(baseAxis, freeAxis) * freeAxis;
if (baseAxis.LengthSquared() < Toolbox.BigEpsilon)
{
//However, if the free axis is totally aligned (like in an axis constraint), pick another reasonable direction.
baseAxis = Vector3.Cross(freeAxis, Vector3.Up);
if (baseAxis.LengthSquared() < Toolbox.BigEpsilon)
{
baseAxis = Vector3.Cross(freeAxis, Vector3.Right);
}
}
Limit.Basis.SetWorldAxes(freeAxis, baseAxis, connectionA.orientationMatrix);
Motor.Basis.SetWorldAxes(freeAxis, baseAxis, connectionA.orientationMatrix);
baseAxis = connectionB.position - anchor;
baseAxis -= Vector3.Dot(baseAxis, freeAxis) * freeAxis;
if (baseAxis.LengthSquared() < Toolbox.BigEpsilon)
{
//However, if the free axis is totally aligned (like in an axis constraint), pick another reasonable direction.
baseAxis = Vector3.Cross(freeAxis, Vector3.Up);
if (baseAxis.LengthSquared() < Toolbox.BigEpsilon)
{
baseAxis = Vector3.Cross(freeAxis, Vector3.Right);
}
}
Limit.TestAxis = baseAxis;
Motor.TestAxis = baseAxis;
Add(BallSocketJoint);
Add(AngularJoint);
Add(Limit);
Add(Motor);
}
MarsRoverMovement roverMovement = new MarsRoverMovement(); // creates the aspects of the rovers movement
#endregion Fields
#region Constructors
public MarsRover()
: base()
{
laserShot = Game1.Instance.Content.Load<SoundEffect>("lasershot");
explosionSound = Game1.Instance.Content.Load<SoundEffect>("explosion-01");
cameraArm = new BepuEntity();
drillArm = new BepuEntity();
//construct mars rover ase body
roverBase = marsRoverBody.AddBox(new Vector3(260, 45, -260));
//create arms to hold both drill and camera/laser
drillArm = marsRoverBody.AddCylinder("cylinder", new Vector3(267, 44, -244), false);
cameraArm = marsRoverBody.AddCylinder("cylinder", new Vector3(254, 54, -252), true);
//Create joint between rover body and drill arm
roverMovement.CreateRevoluteJoint(out roverMovement.bodyDrillJoint, roverBase, drillArm, new Vector3(267, 44, -250), 3500, Vector3.Right);
roverMovement.roverJoints.Add(roverMovement.bodyDrillJoint);
//Create joint between rover body and camera/laser arm
roverMovement.CreateRevoluteJoint(out roverMovement.bodyCameraCylinderJoint, roverBase, cameraArm, cameraArm.body.Position, 1500, Vector3.Up);
roverMovement.roverJoints.Add(roverMovement.bodyCameraCylinderJoint);
//create container for camera/laser
cameraLaserContainer = marsRoverBody.AddCylinder("cube", new Vector3(254, 61, -252), true);
//Create joint between camera/laser arm and container for camera/laser
roverMovement.CreateRevoluteJoint(out roverMovement.cameraLaserContainerXaxisRotation, cameraArm, cameraLaserContainer, cameraLaserContainer.body.Position, 2500, -Vector3.Right);
roverMovement.roverJoints.Add(roverMovement.cameraLaserContainerXaxisRotation);
//create the four back wheels of the rover and connect them to the body
Entity backWheel1 = marsRoverBody.AddWheel(new Vector3(250, 42, -267), roverBase.body);
roverMovement.ConnectWheelBody(backWheel1, roverBase);
Entity backWheel2 = marsRoverBody.AddWheel(new Vector3(270, 42, -267), roverBase.body);
roverMovement.ConnectWheelBody(backWheel2, roverBase);
Entity backWheel3 = marsRoverBody.AddWheel(new Vector3(250, 42, -260), roverBase.body);
roverMovement.ConnectWheelBody(backWheel3, roverBase);
Entity backWheel4 = marsRoverBody.AddWheel(new Vector3(270, 42, -260), roverBase.body);
roverMovement.ConnectWheelBody(backWheel4, roverBase);
//Create the two driving wheels and connect them to the body
var wheel1 = marsRoverBody.AddWheel(new Vector3(270, 42, -255), roverBase.body);
roverMovement.SetUpFrontMotorWheels(roverBase, wheel1, out roverMovement.drivingMotor1, out roverMovement.steeringMotor1);
var wheel2 = marsRoverBody.AddWheel(new Vector3(250, 42, -255), roverBase.body);
roverMovement.SetUpFrontMotorWheels(roverBase, wheel2, out roverMovement.drivingMotor2, out roverMovement.steeringMotor2);
var steeringStabilizer = new RevoluteAngularJoint(wheel1, wheel2, Vector3.Right);
Game1.Instance.Space.Add(steeringStabilizer);
}
/// <summary>
/// Constructs a new constraint which restricts two degrees of linear freedom and two degrees of angular freedom between two entities.
/// </summary>
/// <param name="connectionA">First entity of the constraint pair.</param>
/// <param name="connectionB">Second entity of the constraint pair.</param>
/// <param name="lineAnchor">Location of the anchor for the line to be attached to connectionA in world space.</param>
/// <param name="lineDirection">Axis in world space to be attached to connectionA along which connectionB can move and rotate.</param>
/// <param name="pointAnchor">Location of the anchor for the point to be attached to connectionB in world space.</param>
public LineSliderJoint(Entity connectionA, Entity connectionB, Vector3 lineAnchor, Vector3 lineDirection, Vector3 pointAnchor)
{
if (connectionA == null)
connectionA = TwoEntityConstraint.WorldEntity;
if (connectionB == null)
connectionB = TwoEntityConstraint.WorldEntity;
PointOnLineJoint = new PointOnLineJoint(connectionA, connectionB, lineAnchor, lineDirection, pointAnchor);
AngularJoint = new RevoluteAngularJoint(connectionA, connectionB, lineDirection);
Limit = new LinearAxisLimit(connectionA, connectionB, lineAnchor, pointAnchor, lineDirection, 0, 0);
Motor = new LinearAxisMotor(connectionA, connectionB, lineAnchor, pointAnchor, lineDirection);
Limit.IsActive = false;
Motor.IsActive = false;
Add(PointOnLineJoint);
Add(AngularJoint);
Add(Limit);
Add(Motor);
}
/// <summary>
/// Constructs a new demo.
/// </summary>
/// <param name="game">Game owning this demo.</param>
public ReverseTrikeDemo(DemosGame game)
: base(game)
{
game.Camera.Position = new Vector3(0, 2, 15);
Space.Add(new Box(new Vector3(0, -5, 0), 20, 1, 20));
var body = new Box(new Vector3(0, 0, 0), 2, 1, 3, 10);
body.CollisionInformation.LocalPosition = new Vector3(0, .8f, 0);
Space.Add(body);
#region First Wheel
var wheel = new Cylinder(body.Position + new Vector3(-1.3f, 0, -1.5f), .2f, .5f, 4);
wheel.Material = new Material(1.5f, 1.5f, 0);
wheel.Orientation = Quaternion.CreateFromAxisAngle(Vector3.Forward, MathHelper.PiOver2);
//Preventing the occasional pointless collision pair can speed things up.
CollisionRules.AddRule(body, wheel, CollisionRule.NoBroadPhase);
//Connect the wheel to the body.
var ballSocketJoint = new BallSocketJoint(body, wheel, wheel.Position);
var swivelHingeAngularJoint = new SwivelHingeAngularJoint(body, wheel, Vector3.Up, Vector3.Right);
//Motorize the wheel.
drivingMotor1 = new RevoluteMotor(body, wheel, Vector3.Left);
drivingMotor1.Settings.VelocityMotor.Softness = .2f;
//Let it roll when the user isn't giving specific commands.
drivingMotor1.IsActive = false;
steeringMotor1 = new RevoluteMotor(body, wheel, Vector3.Up);
steeringMotor1.Settings.Mode = MotorMode.Servomechanism;
//The constructor makes a guess about how to set up the constraint.
//It can't always be right since it doesn't have all the information;
//in this case, it chooses the basis and test axis incorrectly.
//This leads to a 'flipping' behavior when the wheel is rolling
//(the test axis is 'rolling' with the wheel, and passes over
//a singularity which causes a flip).
//To fix this, we configure the constraint directly.
//The basis is aligned with how the wheel is set up; we choose 'up' as
//the motorized axis, and right/forward to define the angle measurement plane.
//The test axis is set to be perpendicular to the wheel's rotation so that
//it only measures the steering angle.
//If you're curious, the angle measurement is just a Math.Atan2.
//The current world test axis is dotted against the two plane axes (Right and Forward here).
//This gives an x and y value. These can be plugged into Atan2 just like when
//you compute an angle on a normal 2d graph.
steeringMotor1.Basis.SetWorldAxes(Vector3.Up, Vector3.Right);
steeringMotor1.TestAxis = Vector3.Right;
//Add the wheel and connection to the space.
Space.Add(wheel);
Space.Add(ballSocketJoint);
Space.Add(swivelHingeAngularJoint);
Space.Add(drivingMotor1);
Space.Add(steeringMotor1);
#endregion
#region Second Wheel
wheel = new Cylinder(body.Position + new Vector3(1.3f, 0, -1.5f), .2f, .5f, 4);
wheel.Material = new Material(1.5f, 1.5f, 0);
wheel.Orientation = Quaternion.CreateFromAxisAngle(Vector3.Forward, MathHelper.PiOver2);
//Preventing the occasional pointless collision pair can speed things up.
CollisionRules.AddRule(body, wheel, CollisionRule.NoBroadPhase);
//Connect the wheel to the body.
ballSocketJoint = new BallSocketJoint(body, wheel, wheel.Position);
swivelHingeAngularJoint = new SwivelHingeAngularJoint(body, wheel, Vector3.Up, Vector3.Right);
//Motorize the wheel.
drivingMotor2 = new RevoluteMotor(body, wheel, Vector3.Left);
drivingMotor2.Settings.VelocityMotor.Softness = .2f;
//Let it roll when the user isn't giving specific commands.
drivingMotor2.IsActive = false;
steeringMotor2 = new RevoluteMotor(body, wheel, Vector3.Up);
steeringMotor2.Settings.Mode = MotorMode.Servomechanism;
//Configure the motor. See wheel 1 for more description.
steeringMotor2.Basis.SetWorldAxes(Vector3.Up, Vector3.Right);
steeringMotor2.TestAxis = Vector3.Right;
//Add the wheel and connection to the space.
Space.Add(wheel);
Space.Add(ballSocketJoint);
Space.Add(swivelHingeAngularJoint);
Space.Add(drivingMotor2);
Space.Add(steeringMotor2);
#endregion
#region Third Wheel
wheel = new Cylinder(body.Position + new Vector3(0, -.3f, 1.5f), .2f, .5f, 4);
wheel.Material = new Material(1.5f, 1.5f, 0);
wheel.Orientation = Quaternion.CreateFromAxisAngle(Vector3.Forward, MathHelper.PiOver2);
//Preventing the occasional pointless collision pair can speed things up.
CollisionRules.AddRule(body, wheel, CollisionRule.NoBroadPhase);
//Connect the wheel to the body.
ballSocketJoint = new BallSocketJoint(body, wheel, wheel.Position);
//Notice that the third wheel isn't a swivel hinge, it's just a revolute axis.
//This lets it roll, but prevents flopping around like the wheels of a grocery cart.
//Could have used a RevoluteJoint solver group here, but this shows it's possible to do
//the same things without using the combo-constraints.
var revoluteAngularJoint = new RevoluteAngularJoint(body, wheel, Vector3.Right);
//Add the wheel and connection to the space.
Space.Add(wheel);
Space.Add(ballSocketJoint);
Space.Add(revoluteAngularJoint);
#endregion
int xLength = 180;
int zLength = 180;
float xSpacing = 8f;
float zSpacing = 8f;
var heights = new float[xLength, zLength];
for (int i = 0; i < xLength; i++)
{
for (int j = 0; j < zLength; j++)
{
float x = i - xLength / 2;
float z = j - zLength / 2;
//heights[i,j] = (float)(x * y / 1000f);
heights[i, j] = (float)(10 * (Math.Sin(x / 8) + Math.Sin(z / 8)));
//heights[i,j] = 3 * (float)Math.Sin(x * y / 100f);
//heights[i,j] = (x * x * x * y - y * y * y * x) / 1000f;
}
}
//Create the terrain.
var terrain = new Terrain(heights, new AffineTransform(
new Vector3(xSpacing, 1, zSpacing),
Quaternion.Identity,
new Vector3(-xLength * xSpacing / 2, -10, -zLength * zSpacing / 2)));
Space.Add(terrain);
game.ModelDrawer.Add(terrain);
}
void AddBackWheel(Vector3 wheelOffset, Entity body)
{
var wheel = new Cylinder(body.Position + wheelOffset, .4f, .5f, 5f);
wheel.Material.KineticFriction = 2.5f;
wheel.Material.StaticFriction = 3.5f;
wheel.Orientation = Quaternion.CreateFromAxisAngle(Vector3.Forward, MathHelper.PiOver2);
//Preventing the occasional pointless collision pair can speed things up.
CollisionRules.AddRule(wheel, body, CollisionRule.NoBroadPhase);
//Connect the wheel to the body.
var pointOnLineJoint = new PointOnLineJoint(body, wheel, wheel.Position, Vector3.Down, wheel.Position);
var suspensionLimit = new LinearAxisLimit(body, wheel, wheel.Position, wheel.Position, Vector3.Down, -1, 0);
//This linear axis motor will give the suspension its springiness by pushing the wheels outward.
var suspensionSpring = new LinearAxisMotor(body, wheel, wheel.Position, wheel.Position, Vector3.Down);
suspensionSpring.Settings.Mode = MotorMode.Servomechanism;
suspensionSpring.Settings.Servo.Goal = 0;
suspensionSpring.Settings.Servo.SpringSettings.Stiffness = 300;
suspensionSpring.Settings.Servo.SpringSettings.Damping = 70;
var revoluteAngularJoint = new RevoluteAngularJoint(body, wheel, Vector3.Right);
//Add the wheel and connection to the space.
Space.Add(wheel);
Space.Add(pointOnLineJoint);
Space.Add(suspensionLimit);
Space.Add(suspensionSpring);
Space.Add(revoluteAngularJoint);
}
public JointLimitTestDemo(DemosGame game)
: base(game)
{
float bounciness = 1;
float baseMass = 100;
float armMass = 10;
//DistanceLimit
Box boxA = new Box(new Vector3(-21, 4, 0), 3, 3, 3, baseMass);
Box boxB = new Box(boxA.Position + new Vector3(0, 5, 0), 1, 4, 1, armMass);
CollisionRules.AddRule(boxA, boxB, CollisionRule.NoBroadPhase);
boxB.ActivityInformation.IsAlwaysActive = true;
var distanceLimit = new DistanceLimit(boxA, boxB, boxA.Position, boxB.Position - new Vector3(0, 2, 0), 1, 6);
distanceLimit.Bounciness = bounciness;
Space.Add(boxA);
Space.Add(boxB);
Space.Add(distanceLimit);
//EllipseSwingLimit
boxA = new Box(new Vector3(-14, 4, 0), 3, 3, 3, baseMass);
boxB = new Box(boxA.Position + new Vector3(0, 5, 0), 1, 4, 1, armMass);
CollisionRules.AddRule(boxA, boxB, CollisionRule.NoBroadPhase);
boxB.ActivityInformation.IsAlwaysActive = true;
var ballSocketJoint = new BallSocketJoint(boxA, boxB, boxB.Position + new Vector3(0, -2, 0));
var ellipseSwingLimit = new EllipseSwingLimit(boxA, boxB, Vector3.Up, MathHelper.Pi / 1.5f, MathHelper.Pi / 3);
ellipseSwingLimit.Bounciness = bounciness;
Space.Add(boxA);
Space.Add(boxB);
Space.Add(ballSocketJoint);
Space.Add(ellipseSwingLimit);
//LinearAxisLimit
boxA = new Box(new Vector3(-7, 4, 0), 3, 3, 3, baseMass);
boxB = new Box(boxA.Position + new Vector3(0, 5, 0), 1, 4, 1, armMass);
CollisionRules.AddRule(boxA, boxB, CollisionRule.NoBroadPhase);
boxB.ActivityInformation.IsAlwaysActive = true;
var pointOnLineJoint = new PointOnLineJoint(boxA, boxB, boxA.Position, Vector3.Up, boxB.Position + new Vector3(0, -2, 0));
var linearAxisLimit = new LinearAxisLimit(boxA, boxB, boxA.Position, boxB.Position + new Vector3(0, -2, 0), Vector3.Up, 0, 4);
linearAxisLimit.Bounciness = bounciness;
Space.Add(boxA);
Space.Add(boxB);
Space.Add(pointOnLineJoint);
Space.Add(linearAxisLimit);
//RevoluteLimit
boxA = new Box(new Vector3(0, 4, 0), 3, 3, 3, baseMass);
boxB = new Box(boxA.Position + new Vector3(0, 5, 0), 1, 4, 1, armMass);
CollisionRules.AddRule(boxA, boxB, CollisionRule.NoBroadPhase);
boxB.ActivityInformation.IsAlwaysActive = true;
ballSocketJoint = new BallSocketJoint(boxA, boxB, boxB.Position + new Vector3(0, -2, 0));
var revoluteAngularJoint = new RevoluteAngularJoint(boxA, boxB, Vector3.Forward);
var revoluteLimit = new RevoluteLimit(boxA, boxB, Vector3.Forward, Vector3.Up, -MathHelper.PiOver4, MathHelper.PiOver4);
revoluteLimit.Bounciness = bounciness;
Space.Add(boxA);
Space.Add(boxB);
Space.Add(ballSocketJoint);
Space.Add(revoluteAngularJoint);
Space.Add(revoluteLimit);
//SwingLimit
boxA = new Box(new Vector3(7, 4, 0), 3, 3, 3, baseMass);
boxB = new Box(boxA.Position + new Vector3(0, 5, 0), 1, 4, 1, armMass);
CollisionRules.AddRule(boxA, boxB, CollisionRule.NoBroadPhase);
boxB.ActivityInformation.IsAlwaysActive = true;
ballSocketJoint = new BallSocketJoint(boxA, boxB, boxB.Position + new Vector3(0, -2, 0));
var swingLimit = new SwingLimit(boxA, boxB, Vector3.Up, Vector3.Up, MathHelper.PiOver4);
swingLimit.Bounciness = bounciness;
Space.Add(boxA);
Space.Add(boxB);
Space.Add(ballSocketJoint);
Space.Add(swingLimit);
//TwistLimit
boxA = new Box(new Vector3(14, 4, 0), 3, 3, 3, baseMass);
boxB = new Box(boxA.Position + new Vector3(0, 5, 0), 1, 4, 1, armMass);
CollisionRules.AddRule(boxA, boxB, CollisionRule.NoBroadPhase);
boxB.ActivityInformation.IsAlwaysActive = true;
ballSocketJoint = new BallSocketJoint(boxA, boxB, boxB.Position + new Vector3(0, -2, 0));
revoluteAngularJoint = new RevoluteAngularJoint(boxA, boxB, Vector3.Up);
var twistLimit = new TwistLimit(boxA, boxB, Vector3.Up, Vector3.Up, -MathHelper.PiOver4, MathHelper.PiOver4);
twistLimit.Bounciness = bounciness;
Space.Add(boxA);
Space.Add(boxB);
Space.Add(ballSocketJoint);
Space.Add(revoluteAngularJoint);
Space.Add(twistLimit);
Space.Add(new Box(new Vector3(0, 0, 0), 60, 1, 60));
game.Camera.Position = new Vector3(0, 6, 15);
}
public TreadSegment(Vector3 segmentPosition, Entity body, TreadSegmentDescription treadSegmentDescription)
{
Entity = new Cylinder(segmentPosition, treadSegmentDescription.Width, treadSegmentDescription.Radius, treadSegmentDescription.Mass);
Entity.Material.KineticFriction = treadSegmentDescription.Friction;
Entity.Material.StaticFriction = treadSegmentDescription.Friction;
Entity.Orientation = Quaternion.CreateFromAxisAngle(Vector3.Forward, MathHelper.PiOver2);
//Preventing the occasional pointless collision pair can speed things up.
CollisionRules.AddRule(Entity, body, CollisionRule.NoBroadPhase);
//Connect the wheel to the body.
SuspensionAxisJoint = new PointOnLineJoint(body, Entity, Entity.Position, Vector3.Down, Entity.Position);
SuspensionLengthLimit = new LinearAxisLimit(body, Entity, Entity.Position, Entity.Position, Vector3.Down, -treadSegmentDescription.SuspensionLength, 0);
//This linear axis motor will give the suspension its springiness by pushing the wheels outward.
SuspensionSpring = new LinearAxisMotor(body, Entity, Entity.Position, Entity.Position, Vector3.Down);
SuspensionSpring.Settings.Mode = MotorMode.Servomechanism;
SuspensionSpring.Settings.Servo.Goal = 0;
SuspensionSpring.Settings.Servo.SpringSettings.Stiffness = treadSegmentDescription.SuspensionStiffness;
SuspensionSpring.Settings.Servo.SpringSettings.Damping = treadSegmentDescription.SuspensionDamping;
SuspensionAngularJoint = new RevoluteAngularJoint(body, Entity, Vector3.Right);
//Make the joint extremely rigid. There are going to be extreme conditions when the wheels get up to speed;
//we don't want the forces involved to torque the wheel off the frame!
SuspensionAngularJoint.SpringSettings.Damping *= Entity.Mass * 50;
SuspensionAngularJoint.SpringSettings.Stiffness *= Entity.Mass * 50;
//Motorize the wheel.
Motor = new RevoluteMotor(body, Entity, Vector3.Left);
Motor.Settings.VelocityMotor.Softness = treadSegmentDescription.MotorSoftness;
Motor.Settings.MaximumForce = treadSegmentDescription.MotorMaximumForce;
}