//TODO: Comment better
/// <summary>
/// Moves the body on the path.
/// </summary>
/// <param name="path">The path.</param>
/// <param name="body">The body.</param>
/// <param name="time">The time.</param>
/// <param name="strength">The strength.</param>
/// <param name="timeStep">The time step.</param>
public static void MoveBodyOnPath(Path path, Body body, float time, float strength, float timeStep, bool if_type2 = true)
{
Vector2 destination = path.GetPosition(time);
Vector2 positionDelta = body.Position - destination;
if ( positionDelta.Length() != 0 )
positionDelta.Normalize(); // Added for game
Vector2 velocity = (positionDelta / timeStep) * strength;
Vector2 vel = Math.Min(8,body.LinearVelocity.Length()+3) * -velocity * body.Mass;
if (if_type2 && vel.Length() > 1)
{
float velocity_magnitude_X = Math.Abs(body.LinearVelocity.X);
float velocity_magnitude_Y = Math.Abs(body.LinearVelocity.Y);
float force_magnitude_X = Math.Abs(vel.X);
float force_magnitude_Y = Math.Abs(vel.Y);
bool horiz = force_magnitude_X > 2;
bool vert = force_magnitude_Y > 2;
bool high_vert_low_horiz = (velocity_magnitude_X < velocity_magnitude_Y - 10);
bool high_horiz_low_vert = velocity_magnitude_X > velocity_magnitude_Y + 10;
if ((horiz) && high_vert_low_horiz)
{
vel.X *= 2f;
vel.Y /= 2f;
//body.LinearVelocity = new Vector2(body.LinearVelocity.X,body.LinearVelocity.Y/1.5f);
}
if (vert && high_horiz_low_vert)
{
vel.Y *= 2f;
vel.X /= 2f;
// body.LinearVelocity = new Vector2(body.LinearVelocity.X/1.5f, body.LinearVelocity.Y);
}
if (Math.Sign(vel.Y) != Math.Sign(body.LinearVelocity.Y))
{
vel.Y *= 3;
}
if (Math.Sign(vel.X) != Math.Sign(body.LinearVelocity.X))
{
vel.X *= 3;
}
body.ApplyForce(vel);
}
else if(path.GetLength()>0.5f)
{
body.LinearVelocity = -velocity;
}
}
private void AddBallAndChain(Body body)
{
// The chain will be divided into several segments along the following path
var chainPath = new Path();
chainPath.Add(ConvertUnits.ToSimUnits(332, 332));
chainPath.Add(ConvertUnits.ToSimUnits(332, 452));
// Creates the shape for the chain segments
var chainLinkShape = new PolygonShape(PolygonTools.CreateRectangle(ConvertUnits.ToSimUnits(1), ConvertUnits.ToSimUnits(2)), 0.5f);
// Creates the bodies for the chain segments
_chainBodies = PathManager.EvenlyDistributeShapesAlongPath(World, chainPath,
new[] {chainLinkShape}, BodyType.Dynamic, 30);
// Connects the chain segments
for (var i = 0; i < _chainBodies.Count - 1; i++)
{
var joint = new RevoluteJoint(_chainBodies[i], _chainBodies[i + 1], Vector2.Zero, Vector2.Zero);
World.AddJoint(joint);
}
// Connects the start of the chain to the ufo
var chainStartJoint = new RevoluteJoint(body, _chainBodies.First(), ConvertUnits.ToSimUnits(0, 25), Vector2.Zero);
World.AddJoint(chainStartJoint);
// Creates the ball at the end of the chain
_chainEndBall = BodyFactory.CreateCircle(World, ConvertUnits.ToSimUnits(10), 3f, bodyType: BodyType.Dynamic);
_chainEndBall.Position = ConvertUnits.ToSimUnits(332, 452);
_chainEndBall.OnCollision += ChainBallOnCollision;
// Adds the ball to the chain
var chainEndJoint = new RevoluteJoint(_chainBodies.Last(), _chainEndBall, Vector2.Zero, Vector2.Zero);
World.AddJoint(chainEndJoint);
// Adds a rope join that ensures that the chain won't stretch
var ropeJoint = new RopeJoint(body, _chainEndBall, ConvertUnits.ToSimUnits(0, 25), Vector2.Zero)
{
MaxLength = chainPath.GetLength()
};
World.AddJoint(ropeJoint);
}
