com.jme3.ai.agents.behaviors.npc.steering

Class ObstacleAvoidanceBehavior

java.lang.Object

com.jme3.scene.control.AbstractControl

com.jme3.ai.agents.behaviors.Behavior

com.jme3.ai.agents.behaviors.npc.steering.AbstractSteeringBehavior

com.jme3.ai.agents.behaviors.npc.steering.AbstractStrengthSteeringBehavior

com.jme3.ai.agents.behaviors.npc.steering.ObstacleAvoidanceBehavior

All Implemented Interfaces:

com.jme3.export.Savable, com.jme3.scene.control.Control

Direct Known Subclasses:

UnalignedCollisionAvoidanceBehavior

public class ObstacleAvoidanceBehavior
extends AbstractStrengthSteeringBehavior

Returns a steering force to avoid a given obstacle. The purely lateral steering force will turn our vehicle towards a silhouette edge of the obstacle. Avoidance is required when (1) the obstacle intersects the vehicle's current path, (2) it is in front of the vehicle, and (3) is within minTimeToCollision seconds of travel at the vehicle's current velocity. Returns a zero vector value when no avoidance is required.

The implementation of obstacle avoidance behavior here will make a simplifying assumption that both the character and obstacle can be reasonably approximated as spheres.

Keep in mind that this relates to obstacle avoidance not necessarily to collision detection.

The goal of the behavior is to keep an imaginary cylinder of free space in front of the character. The cylinder lies along the character's forward axis, has a diameter equal to the character's bounding sphere, and extends from the character's center for a distance based on the character's velocity.

It is needed that the obstacles (Agents) have the "radius" atribute correctly setted up.

Version:

1.1.1

Author:

Jesús Martín Berlanga

See Also:

GameEntity.setRadius(float)

Field Summary

Fields inherited from class com.jme3.ai.agents.behaviors.npc.steering.AbstractSteeringBehavior

timePerFrame, velocity

Fields inherited from class com.jme3.ai.agents.behaviors.Behavior

agent

Fields inherited from class com.jme3.scene.control.AbstractControl

enabled, spatial

Constructor Summary

Constructors

Constructor and Description
ObstacleAvoidanceBehavior(Agent agent, java.util.List<GameEntity> obstacles, float minTimeToCollision)
ObstacleAvoidanceBehavior(Agent agent, java.util.List<GameEntity> obstacles, float minTimeToCollision, float minDistance)
ObstacleAvoidanceBehavior(Agent agent, java.util.List<GameEntity> obstacles, float minTimeToCollision, float minDistance, com.jme3.scene.Spatial spatial)
ObstacleAvoidanceBehavior(Agent agent, java.util.List<GameEntity> obstacles, float minTimeToCollision, com.jme3.scene.Spatial spatial)

Method Summary

Methods

Modifier and Type	Method and Description
protected com.jme3.math.Vector3f	calculateRawSteering() If a behavior class extend from CompoundSteeringBehaviour instead of AbstractSteeringBehavior, it must implement this method instead of calculateSteering().
protected float	getMinDistance()
protected float	getMinTimeToCollision()
protected java.util.List<GameEntity>	getObstacles()
protected com.jme3.math.Vector3f	randomVectInPlane(com.jme3.math.Vector3f planeNormalV, com.jme3.math.Vector3f planePoint) Generates a random vector inside a plane defined by a normal vector and a point
void	setObstacles(java.util.List<GameEntity> obstacles)

Methods inherited from class com.jme3.ai.agents.behaviors.npc.steering.AbstractStrengthSteeringBehavior

calculateSteering, setupStrengthControl, setupStrengthControl, setupStrengthControl, setupStrengthControl, setupStrengthControl, turnOffStrengthControl

Methods inherited from class com.jme3.ai.agents.behaviors.npc.steering.AbstractSteeringBehavior

agentTotalMass, calculateNewVelocity, controlUpdate, convertToGameEntities, getBrakingFactor, getTimePerFrame, getVelocity, rotateAgent, setBrakingFactor, setTimePerFrame, setVelocity

Methods inherited from class com.jme3.ai.agents.behaviors.Behavior

controlRender

Methods inherited from class com.jme3.scene.control.AbstractControl

cloneForSpatial, getSpatial, isEnabled, read, render, setEnabled, setSpatial, update, write

Methods inherited from class java.lang.Object

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

Constructor Detail

ObstacleAvoidanceBehavior

public ObstacleAvoidanceBehavior(Agent agent,
                         java.util.List<GameEntity> obstacles,
                         float minTimeToCollision)

Parameters:

obstacles - A list with the obstacles (Agents)

minTimeToCollision - When the time to collision is lower than this value the steer force will appear. Time is measured in seconds.

Throws:

SteeringExceptions.NegativeValueException - If minTimeToCollision is lower or equals to 0

See Also:

AbstractSteeringBehavior.AbstractSteeringBehavior(com.jme3.ai.agents.Agent)

ObstacleAvoidanceBehavior

public ObstacleAvoidanceBehavior(Agent agent,
                         java.util.List<GameEntity> obstacles,
                         float minTimeToCollision,
                         com.jme3.scene.Spatial spatial)

See Also:

ObstacleAvoidanceBehavior(com.jme3.ai.agents.Agent, java.util.List, float), AbstractSteeringBehavior.AbstractSteeringBehavior(com.jme3.ai.agents.Agent, com.jme3.scene.Spatial)

ObstacleAvoidanceBehavior

public ObstacleAvoidanceBehavior(Agent agent,
                         java.util.List<GameEntity> obstacles,
                         float minTimeToCollision,
                         float minDistance)

Parameters:

minDistance - Min. distance from center to center to consider an obstacle

Throws:

SteeringExceptions.NegativeValueException - If minTimeToCollision is lower than 0

See Also:

ObstacleAvoidanceBehavior(com.jme3.ai.agents.Agent, java.util.List, float)

ObstacleAvoidanceBehavior

public ObstacleAvoidanceBehavior(Agent agent,
                         java.util.List<GameEntity> obstacles,
                         float minTimeToCollision,
                         float minDistance,
                         com.jme3.scene.Spatial spatial)

See Also:

ObstacleAvoidanceBehavior#ObstacleAvoidanceBehavior(com.jme3.ai.agents.Agent, com.jme3.scene.Spatial, java.util.List, float), AbstractSteeringBehavior.AbstractSteeringBehavior(com.jme3.ai.agents.Agent, com.jme3.scene.Spatial)

Method Detail

calculateRawSteering

protected com.jme3.math.Vector3f calculateRawSteering()

Description copied from class: AbstractStrengthSteeringBehavior

If a behavior class extend from CompoundSteeringBehaviour instead of AbstractSteeringBehavior, it must implement this method instead of calculateSteering().

Specified by:

calculateRawSteering in class AbstractStrengthSteeringBehavior

Returns:

See Also:

AbstractSteeringBehavior.calculateSteering()

randomVectInPlane

protected com.jme3.math.Vector3f randomVectInPlane(com.jme3.math.Vector3f planeNormalV,
                                       com.jme3.math.Vector3f planePoint)

Generates a random vector inside a plane defined by a normal vector and a point

getObstacles

protected java.util.List<GameEntity> getObstacles()

setObstacles

public void setObstacles(java.util.List<GameEntity> obstacles)

getMinTimeToCollision

protected float getMinTimeToCollision()

getMinDistance

protected float getMinDistance()