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

Class PathFollowBehavior

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.PathFollowBehavior

All Implemented Interfaces:

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

public class PathFollowBehavior
extends AbstractStrengthSteeringBehavior

"Path following behavior enables a character to steer along a predetermined path, such as a roadway, corridor or tunnel. This is distinct from constraining a vehicle rigidly to a path like a train rolling along a track. Rather path following behavior is intended to produce motion such as people moving down a corridor: the individual paths remain near, and often parallel to, the centerline of the corridor, but are free to deviate from it. In the implementation described here, a path will be idealized as a spine and a radius. The spine" is represented as a "poly-line (a series of connected line segments). The path is then a tube or generalized cylinder: a circle of the specified radius, swept along the specified spine. The goal of the path following steering behavior is to move a character along the path while taying within the specified radius of the spine. If the character is initially far away from the path, it must first approach, then follow the path."

"To compute steering for path following, a velocity-based prediction is made of the character's future position. The predicted future position is projected onto the nearest point on the path spine. If this projection distance (from the predicted position to the nearest on-path point) is less than the path radius, then the character is deemed to be correctly following the path and no corrective steering is required. Otherwise the character is veering away from the path, or is too far away from the path. To steer back towards the path, the seek behavior is used to steer towards the on-path projection of the predicted future position. A null or zero value is returned if no corrective steering is required."

If you need the agent to pass exactly from the beginning of the first spine you must use seek before activating path follow.

Version:

1.0.1

Author:

Jesús Martín Berlanga

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
PathFollowBehavior(Agent agent, java.util.ArrayList<com.jme3.math.Vector3f> orderedPointsList, float pathRadius)
PathFollowBehavior(Agent agent, java.util.ArrayList<com.jme3.math.Vector3f> orderedPointsList, float pathRadius, float cohesionStrength)
PathFollowBehavior(Agent agent, java.util.ArrayList<com.jme3.math.Vector3f> orderedPointsList, float pathRadius, float cohesionStrength, com.jme3.scene.Spatial spatial)
PathFollowBehavior(Agent agent, java.util.ArrayList<com.jme3.math.Vector3f> orderedPointsList, float pathRadius, 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().
boolean	isActive()
void	reset() Reset the behavior.
void	setActive(boolean active)

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

PathFollowBehavior

public PathFollowBehavior(Agent agent,
                  java.util.ArrayList<com.jme3.math.Vector3f> orderedPointsList,
                  float pathRadius)

Parameters:

orderedPointsList - Ordered points that will set the path spine and consequently the path route. The minimum number of points is two.

pathRadius - Spine radius i.e the path width

Throws:

SteeringExceptions.PathFollowInsufficientPointsException - If orderedPointsList size is lower than 2

SteeringExceptions.NegativeValueException - If path radius is negative

See Also:

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

PathFollowBehavior

public PathFollowBehavior(Agent agent,
                  java.util.ArrayList<com.jme3.math.Vector3f> orderedPointsList,
                  float pathRadius,
                  com.jme3.scene.Spatial spatial)

See Also:

PathFollowBehavior(com.jme3.ai.agents.Agent, java.util.ArrayList, float), AbstractStrengthSteeringBehavior.AbstractStrengthSteeringBehavior(com.jme3.ai.agents.Agent, com.jme3.scene.Spatial)

PathFollowBehavior

public PathFollowBehavior(Agent agent,
                  java.util.ArrayList<com.jme3.math.Vector3f> orderedPointsList,
                  float pathRadius,
                  float cohesionStrength)

Parameters:

cohesionStrength - Cohesion multiplier

Throws:

PathFollowNegativeCohesionStrengthException - If cohesionStrength is negative

See Also:

PathFollowBehavior(com.jme3.ai.agents.Agent, java.util.ArrayList, float)

PathFollowBehavior

public PathFollowBehavior(Agent agent,
                  java.util.ArrayList<com.jme3.math.Vector3f> orderedPointsList,
                  float pathRadius,
                  float cohesionStrength,
                  com.jme3.scene.Spatial spatial)

Parameters:

cohesionStrength - Cohesion multiplier

See Also:

PathFollowBehavior(com.jme3.ai.agents.Agent, java.util.ArrayList, float, com.jme3.scene.Spatial)

Method Detail

reset

public void reset()

Reset the behavior. The agent will start following the path again from the beginning.

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:

AbstractStrengthSteeringBehavior.calculateRawSteering()

setActive

public void setActive(boolean active)

isActive

public boolean isActive()