com.badlogic.gdx.ai.steer.behaviors

Class CollisionAvoidance<T extends com.badlogic.gdx.math.Vector<T>>

java.lang.Object

com.badlogic.gdx.ai.steer.SteeringBehavior<T>

com.badlogic.gdx.ai.steer.GroupBehavior<T>

com.badlogic.gdx.ai.steer.behaviors.CollisionAvoidance<T>

Type Parameters:

T - Type of vector, either 2D or 3D, implementing the Vector interface

All Implemented Interfaces:

Proximity.ProximityCallback<T>

public class CollisionAvoidance<T extends com.badlogic.gdx.math.Vector<T>>
extends GroupBehavior<T>
implements Proximity.ProximityCallback<T>

CollisionAvoidance behavior steers the owner to avoid obstacles lying in its path. An obstacle is any object that can be approximated by a circle (or sphere, if you are working in 3D).

This implementation uses collision prediction working out the closest approach of two agents and determining if their distance at this point is less than the sum of their bounding radius. For avoiding groups of characters, averaging positions and velocities do not work well with this approach. Instead, the algorithm needs to search for the character whose closest approach will occur first and to react to this character only. Once this imminent collision is avoided, the steering behavior can then react to more distant characters.

This algorithm works well with small and/or moving obstacles whose shape can be approximately represented by a center and a radius.

Field Summary

Fields inherited from class com.badlogic.gdx.ai.steer.GroupBehavior

proximity

Fields inherited from class com.badlogic.gdx.ai.steer.SteeringBehavior

enabled, limiter, owner

Constructor Summary

Constructors

Constructor and Description
CollisionAvoidance(Steerable<T> owner, Proximity<T> proximity) Creates a CollisionAvoidance behavior for the specified owner and proximity.

Method Summary

Modifier and Type	Method and Description
protected SteeringAcceleration<T>	calculateRealSteering(SteeringAcceleration<T> steering) Calculates the steering acceleration produced by this behavior and writes it to the given steering output.
boolean	reportNeighbor(Steerable<T> neighbor) The callback method used to report a neighbor.
CollisionAvoidance<T>	setEnabled(boolean enabled) Sets this steering behavior on/off.
CollisionAvoidance<T>	setLimiter(Limiter limiter) Sets the limiter of this steering behavior.
CollisionAvoidance<T>	setOwner(Steerable<T> owner) Sets the owner of this steering behavior.

Methods inherited from class com.badlogic.gdx.ai.steer.GroupBehavior

getProximity, setProximity

Methods inherited from class com.badlogic.gdx.ai.steer.SteeringBehavior

calculateSteering, getActualLimiter, getLimiter, getOwner, isEnabled, newVector

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

CollisionAvoidance

public CollisionAvoidance(Steerable<T> owner,
                          Proximity<T> proximity)

Creates a CollisionAvoidance behavior for the specified owner and proximity.

Parameters:

owner - the owner of this behavior

proximity - the proximity of this behavior.

Method Detail

calculateRealSteering

protected SteeringAcceleration<T> calculateRealSteering(SteeringAcceleration<T> steering)

Description copied from class: SteeringBehavior

Calculates the steering acceleration produced by this behavior and writes it to the given steering output.

This method is called by SteeringBehavior.calculateSteering(SteeringAcceleration) when this steering behavior is enabled.

Specified by:

calculateRealSteering in class SteeringBehavior<T extends com.badlogic.gdx.math.Vector<T>>

Parameters:

steering - the steering acceleration to be calculated.

Returns:

the calculated steering acceleration for chaining.

reportNeighbor

public boolean reportNeighbor(Steerable<T> neighbor)

Description copied from interface: Proximity.ProximityCallback

The callback method used to report a neighbor.

Specified by:

reportNeighbor in interface Proximity.ProximityCallback<T extends com.badlogic.gdx.math.Vector<T>>

Parameters:

neighbor - the reported neighbor.

Returns:

true if the given neighbor is valid; false otherwise.

setOwner

public CollisionAvoidance<T> setOwner(Steerable<T> owner)

Description copied from class: SteeringBehavior

Sets the owner of this steering behavior.

Overrides:

setOwner in class SteeringBehavior<T extends com.badlogic.gdx.math.Vector<T>>

Returns:

this behavior for chaining.

setEnabled

public CollisionAvoidance<T> setEnabled(boolean enabled)

Description copied from class: SteeringBehavior

Sets this steering behavior on/off.

Overrides:

setEnabled in class SteeringBehavior<T extends com.badlogic.gdx.math.Vector<T>>

Returns:

this behavior for chaining.

setLimiter

public CollisionAvoidance<T> setLimiter(Limiter limiter)

Sets the limiter of this steering behavior. The given limiter must at least take care of the maximum linear acceleration.

Overrides:

setLimiter in class SteeringBehavior<T extends com.badlogic.gdx.math.Vector<T>>

Returns:

this behavior for chaining.