SteeringBehaviors

• SB_Behaviors

  Methods:

  • Align (V As SB_Vehicle, RadiusAround As Float) As SB_Vector2D
    Returns a steering vector that aligns the vehicle with other nearby vehicles of its group. RadiusAround: Radius of the area to be searched for other vehicles.
  • Arrive (Seeker As SB_Vehicle, Destination As SB_Vector2D, ArrivalRadius As Float) As SB_Vector2D
    Returns a steering vector that reduces the seeker's velocity as it approaches the given destination. ArrivalRadius: Radius of the arrival area in which the vehicle decelerates.
  • AvoidObstacles (V As SB_Vehicle, VehicleSize As Float, Obstacles As SB_Obstacles, RadiusAround As Float) As SB_Vector2D
    Returns a steering vector that aims to avoid the obstacles in the vehicle's path. VehicleSize: Largest dimension of the vehicle. Obstacles: Obstacles to avoid. RadiusAround: Radius of the area to be searched for obstacles.
  • Cohere (V As SB_Vehicle, RadiusAround As Float) As SB_Vector2D
    Returns a steering vector that directs the vehicle toward the other vehicles of its group. RadiusAround: Radius of the area to be searched for other vehicles.
  • Combine (V As SB_Vehicle, SteeringVectors() As SB_Vector2D) As SB_Vector2D
    Combines the specified steering vectors.
  • Evade (Fleer As SB_Vehicle, Predator As SB_Vehicle) As SB_Vector2D
    Returns a steering vector fleeing from the given predator.
  • Flee (Fleer As SB_Vehicle, Undesired As SB_Vector2D) As SB_Vector2D
    Returns a steering vector that flees the given location.
  • FollowPath (Seeker As SB_Vehicle, Waypoints() As SB_Vector2D, WaypointRadius As Float, WithArrival As Boolean, ArrivalRadius As Float) As SB_Vector2D
    Returns a steering vector that seeks the waypoints of a predefined path. Waypoints(): Array of waypoints. WaypointRadius: Radius of each waypoint. When the seeker enters this radius, the next waypoint is selected. WithArrival: If True, the selected behavior is Arrive. If False, it is Seek. ArrivalRadius: Radius of the arrival area in which the vehicle decelerates. Relevant when WithArrival=True.
  • Pursue (Pursuer As SB_Vehicle, Quarry As SB_Vehicle) As SB_Vector2D
    Returns a steering vector that seeks the future location of the given quarry.
  • Seek (Seeker As SB_Vehicle, Desired As SB_Vector2D) As SB_Vector2D
    Returns a steering vector that seeks the desired location.
  • Separate (V As SB_Vehicle, DistanceBetween As Float) As SB_Vector2D
    Returns a steering vector that keeps the vehicle at a certain distance from other vehicles of its group. DistanceBetween: Distance between the vehicles.
  • Wander (Wanderer As SB_Vehicle, Radius As Float, MaxChange As Double, MaxAngle As Double) As SB_Vector2D
    Returns a steering vector that moves the vehicle randomly. To determine the new direction, a circle is drawn in front of the vehicle and a random point is picked along its circumference. This keeps the vehicle's movement from appearing jittery. Radius: Radius of the "wander circle" MaxChange: Maximum amount of change in angle (radians) MaxAngle: Maximum steering angle (radians)

• SB_Group

  Methods:

  • AddVehicle (vehicle As SB_Vehicle) As Boolean
    Adds the given vehicle to this group. A vehicle may belong to only one group. If it belongs already to another group, it is removed before being added to this group.
  • Clear
    Removes all vehicles from this group.
  • Contains (vehicle As SB_Vehicle) As Boolean
    Returns True if the given vehicle belongs to this group.
  • GetNearVehicles (V As SB_Vehicle, Distance As Float, VisionAngle As Double) As List
    Returns a list of vehicles whose distance from the vehicle is less than the specified distance. V: Vehicle used as center for search. Distance: Maximum distance from V. VisionAngle: Angle in radians of the visual field. Only vehicles in the visual field of V will be taken into account. Set this value to 0 (or 2 * Pi) for a circular view.
  • Initialize
    Initializes a new group of vehicles. Groups are used by the functions: Align, Cohere, Separate, and View.
  • ListAll As List
    Returns a list with all vehicles belonging to this group.
  • RemoveVehicle (vehicle As SB_Vehicle) As Boolean
    Removes the given vehicle from this group.

  Properties:

  • IsInitialized As Boolean [read only]

• SB_Obstacle

  Fields:

  • SHAPE_4WALLS As Byte
  • SHAPE_CIRCLE As Byte
  • SHAPE_RECT As Byte

  Methods:

  • CreateCircle (Radius As Float, CenterPosition As SB_Vector2D, Impassable As Boolean)
    Creates a circular obstacle. Radius: Radius of the circle. CenterPosition: Position of the center of the circle. Impassable: If True, a vehicle cannot pass through this obstacle.
  • CreateFourWalls (Width As Float, Height As Float, CenterPosition As SB_Vector2D, Impassable As Boolean)
    Creates a rectangular area surrounded by four walls. Each wall is an obstacle. This may be used to prevent vehicles from going off screen. Width,Height: Dimensions of the rectangular area. CenterPosition: Position of the center of the rectangular area. Impassable: If True, a vehicle cannot pass through the walls.
  • CreateRect (Width As Float, Height As Float, CenterPosition As SB_Vector2D, Impassable As Boolean)
    Creates a rectangular obstacle. Width,Height: Dimensions of the rectangle. CenterPosition: Position of the center of the rectangle. Impassable: If True, a vehicle cannot pass through this obstacle.
  • GetDistanceTo (Position As SB_Vector2D) As Float
    Returns the distance between the given position and the closest boundary of this obstacle. 0 = collision/overlapping.

  Properties:

  • Bottom As Float [read only]
  • Height As Float
  • Impassable As Boolean [read only]
  • IsInitialized As Boolean [read only]
  • Left As Float [read only]
  • Position As SB_Vector2D
    Gets/sets the center position.
  • Radius As Float
  • Right As Float [read only]
  • ShapeType As Byte [read only]
  • Tag As Object
  • Top As Float [read only]
  • Width As Float

• SB_Obstacles

  Methods:

  • AddObstacle (Obstacle As SB_Obstacle)
  • Contains (Obstacle As SB_Obstacle) As Boolean
  • GetNearObstacles (Pos As SB_Vector2D, Distance As Float) As Map
    Returns a Map containing the obstacles whose distance from the position is less than the specified distance. Map key = obstacle, Map value = distance to obstacle. Pos: Position used as center for search. Distance: Maximum distance from Pos.
  • Initialize
  • ListAll As List
    Returns a list with all obstacles.
  • RemoveAllObstacles
  • RemoveObstacle (Obstacle As SB_Obstacle)

  Properties:

  • IsInitialized As Boolean [read only]

• SB_Vector2D

  Methods:

  • Add (v As SB_Vector2D) As SB_Vector2D
    Adds the given vector to this vector.
  • AngleWith (vOther As SB_Vector2D) As Double
    Calculates the angle in radians between this vector and another vector.
  • Clone (v As SB_Vector2D)
    Copies X and Y of another vector.
  • Cross (v As SB_Vector2D) As Float
    Calculates the cross product of two vectors.
  • Deg2Rad (Degrees As Double) As Double
    Converts degrees to radians.
  • Divide (by As Float) As SB_Vector2D
    Divides the vector by a float value.
  • Dot (v As SB_Vector2D) As Float
    Calculates the dot product of two vectors.
  • Initialize (X As Float, Y As Float)
    Initializes an object that represents a position or a vector in two-dimensional space.
  • Multiply (by As Float) As SB_Vector2D
    Multiplies the vector by a float value.
  • Negate As SB_Vector2D
    Returns the negation of this vector.
  • Normalize As SB_Vector2D
    Returns a vector of length 1.0 with the same direction as this vector.
  • Project (vOnto As SB_Vector2D) As SB_Vector2D
    Projects this vector onto the given vector.
  • Rad2Deg (Radians As Double) As Double
    Converts radians to degrees.
  • Subtract (v As SB_Vector2D) As SB_Vector2D
    Subtracts the given vector from this vector.
  • equals (obj As Object) As Boolean
    Determines equality to three decimal places.

  Properties:

  • Angle As Double
    Gets/sets the angle in radians of this vector.
  • IsInitialized As Boolean [read only]
  • Length As Float
    Gets/sets the length of this vector.
  • SquaredLength As Float [read only]
    Gets the squared length of this vector.
  • X As Float
  • Xdip As Float [read only]
    Returns the X position * density.
  • Y As Float
  • Ydip As Float [read only]
    Returns the Y position * density.

• SB_Vehicle

  Methods:

  • Clone (V As SB_Vehicle)
    Copies all data of another vehicle except its group.
  • GetAngleWith (Position As SB_Vector2D) As Double
    Returns the angle in radians between this vehicle and the given position. Negative = the given position is on the left. Positive = the given position is on the right. < PI / 2 = the given position is in front. > PI / 2 = the given position is behind.
  • GetDistanceTo (Position As SB_Vector2D) As Float
    Returns the distance between this vehicle and the given position.
  • Initialize (Mass As Float, Position As SB_Vector2D, Velocity As SB_Vector2D)
  • Move
    Adds the vehicle velocity to its current position.
  • Steer (SteeringForce As SB_Vector2D)
    Applies a steering force to the vehicle velocity. This steering force is limited by MaxForce, then divided by the vehicle mass.
  • Steer2 (SteeringForce As SB_Vector2D)
    Applies a steering force to the vehicle velocity. This steering force is divided by the vehicle mass, then limited by MaxForce.

  Properties:

  • FuturePosition As SB_Vector2D [read only]
    Computes the future position based on the current velocity.
  • IsInitialized As Boolean [read only]
  • Mass As Float
  • MaxForce As Float
    Gets/sets the maximum amount of change in velocity (default = 1.5).
  • MaxSpeed As Float
    Gets/sets the maximum allowable velocity (default = 1.5).
  • Position As SB_Vector2D
  • Tag As Object
  • Velocity As SB_Vector2D
  • Waypoint As Int
    Gets/sets the current waypoint when the selected behavior is FollowPath.

• Author: F. Leneuf-Magaud

• Version: 1