/**
* Copyright (c) 2014, jMonkeyEngine All rights reserved.
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* Redistributions of source code must retain the above copyright notice, this
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* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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package com.jme3.ai.agents.behaviors.npc.steering;
import com.jme3.ai.agents.Agent;
import com.jme3.ai.agents.behaviors.npc.steering.SteeringExceptions.WallApproachWithoutWallException;
import com.jme3.collision.CollisionResult;
import com.jme3.collision.CollisionResults;
import com.jme3.math.Ray;
import com.jme3.math.Vector3f;
import com.jme3.scene.Node;
import com.jme3.scene.Spatial;
/**
* "Approach a 'wall' (or other surface or path) and then maintain a certain
* offset from it" <br><br>
*
* Keep in mind that this relates to wall approach not necessarily to collision
* detection.
*
* @author Jesús Martín Berlanga
* @version 1.1
*/
public class WallApproachBehavior extends AbstractStrengthSteeringBehavior {
//14 tests in total
private static enum RayTests {
RAY_TEST_X(Vector3f.UNIT_X),
RAY_TEST_Y(Vector3f.UNIT_Y),
RAY_TEST_Z(Vector3f.UNIT_Z),
RAY_TEST_NEGX(Vector3f.UNIT_X.negate()),
RAY_TEST_NEGY(Vector3f.UNIT_Y.negate()),
RAY_TEST_NEGZ(Vector3f.UNIT_Z.negate()),
RAY_TEST_XZ_UP(new Vector3f(1, 1, 1)),
RAY_TEST_NEGX_Z_UP(new Vector3f(-1, 1, 1)),
RAY_TEST_X_NEGZ_UP(new Vector3f(1, 1, -1)),
RAY_TEST_NEGXZ_UP(new Vector3f(-1, 1, -1)),
RAY_TEST_XZ_DOWN(new Vector3f(1, -1, 1)),
RAY_TEST_NEGX_Z_DOWN(new Vector3f(-1, -1, 1)),
RAY_TEST_X_NEGZ_DOWN(new Vector3f(1, -1, -1)),
RAY_TEST_NEGXZ_DOWN(new Vector3f(-1, -1, -1));
private Vector3f direction;
private RayTests(Vector3f direction) {
this.direction = direction;
}
private Vector3f getDirection() {
return this.direction;
}
}
private Node wall;
private float offsetToMaintain;
private float rayTestOffset;
private static final float MIN_RAY_TEST_OFFSET = 0.001f;
/**
* @throws SteeringExceptions.NegativeValueException If offsetToMaintain is
* negative
*/
public void setOffsetToMaintain(float offsetToMaintain) {
WallApproachBehavior.validateOffsetToMaintain(offsetToMaintain);
this.offsetToMaintain = offsetToMaintain;
}
/**
* @param wall Surface or path where the agent will maintain a certain
* offset
* @paaram offsetToMaintain Offset from the surface that the agent will have
* to maintain
*
* @throws WallApproachWithoutWallException If the wall is a null pointer
* @throws SteeringExceptions.NegativeValueException If offsetToMaintain is
* negative
*
* @see
* AbstractStrengthSteeringBehavior#AbstractStrengthSteeringBehavior(com.jme3.ai.agents.Agent)
*/
public WallApproachBehavior(Agent agent, Node wall, float offsetToMaintain) {
super(agent);
WallApproachBehavior.validateConstruction(wall, offsetToMaintain);
this.wall = wall;
this.offsetToMaintain = offsetToMaintain;
if (offsetToMaintain != 0) {
this.rayTestOffset = (offsetToMaintain + agent.getRadius()) * 4;
} else {
this.rayTestOffset = WallApproachBehavior.MIN_RAY_TEST_OFFSET;
}
}
/**
* @see WallApproach#WallApproach(com.jme3.ai.agents.Agent,
* com.jme3.scene.Node, float)
* @see
* AbstractStrengthSteeringBehavior#AbstractStrengthSteeringBehavior(com.jme3.ai.agents.Agent,
* com.jme3.scene.Spatial)
*/
public WallApproachBehavior(Agent agent, Node wall, float offsetToMaintain, Spatial spatial) {
super(agent, spatial);
WallApproachBehavior.validateConstruction(wall, offsetToMaintain);
this.wall = wall;
this.offsetToMaintain = offsetToMaintain;
if (offsetToMaintain != 0) {
this.rayTestOffset = (offsetToMaintain + agent.getRadius()) * 4;
} else {
this.rayTestOffset = WallApproachBehavior.MIN_RAY_TEST_OFFSET;
}
}
private static void validateConstruction(Node wall, float offsetToMaintain) {
if (wall == null) {
throw new WallApproachWithoutWallException("You can not instantiate a new wall approach behaviour without a wall.");
} else {
WallApproachBehavior.validateOffsetToMaintain(offsetToMaintain);
}
}
private static void validateOffsetToMaintain(float offsetToMaintain) {
if (offsetToMaintain < 0) {
throw new SteeringExceptions.NegativeValueException("The superficial offset to maintain cannot be negative.", offsetToMaintain);
}
}
/**
* @see AbstractStrengthSteeringBehavior#calculateRawSteering()
*/
@Override
protected Vector3f calculateRawSteering() {
Vector3f steer = new Vector3f();
Vector3f aproximatedSurfaceLocationDir = this.approximateSurfaceLocation();
if (aproximatedSurfaceLocationDir != null) {
Vector3f surfaceLocation = this.surfaceLocation(aproximatedSurfaceLocationDir);
if (surfaceLocation != null) {
Vector3f extraOffset = this.agent.offset(surfaceLocation).negate().normalize().mult(this.offsetToMaintain);
SeekBehavior seek = new SeekBehavior(this.agent, surfaceLocation.add(extraOffset));
steer = seek.calculateRawSteering();
}
}
return steer;
}
/**
* Check for intersections with the wall - Ray test
*/
private Vector3f approximateSurfaceLocation() {
class LowerDistances {
private Vector3f[] lowerDistances = new Vector3f[]{
Vector3f.POSITIVE_INFINITY,
Vector3f.POSITIVE_INFINITY,
Vector3f.POSITIVE_INFINITY,};
private void addDistance(Vector3f distance) {
float distanceLength = distance.length();
int lowerPos = -1;
float currentLength = Float.MAX_VALUE;
for (int i = 0; i < lowerDistances.length; i++) {
float length = lowerDistances[i].length();
if (length > currentLength) {
currentLength = length;
lowerPos = i;
}
}
if (lowerPos != -1 && lowerDistances[lowerPos].length() > distanceLength) {
lowerDistances[lowerPos] = distance;
}
}
private Vector3f distanceSum() {
Vector3f sum = new Vector3f();
boolean almostOne = false;
for (int i = 0; i < lowerDistances.length; i++) {
if (lowerDistances[i] != null && lowerDistances[i].length() < rayTestOffset) {
sum = sum.add(lowerDistances[i]);
almostOne = true;
}
}
if (almostOne) {
return sum;
} else {
return null;
}
}
}
LowerDistances distances = new LowerDistances();
for (RayTests rayTest : WallApproachBehavior.RayTests.values()) {
Vector3f rayTestSurfaceLocation = this.surfaceLocation(rayTest.getDirection());
if (rayTestSurfaceLocation != null) {
distances.addDistance(agent.offset(rayTestSurfaceLocation));
}
}
return distances.distanceSum();
}
private Vector3f surfaceLocation(Vector3f direction) {
Vector3f surfaceLocation = null;
CollisionResults results = new CollisionResults();
Ray ray = new Ray(this.agent.getLocalTranslation(), direction);
this.wall.collideWith(ray, results);
CollisionResult collisionResult = results.getClosestCollision();
if (collisionResult != null && !Float.isNaN(collisionResult.getDistance()) && !Float.isInfinite(collisionResult.getDistance())) {
surfaceLocation = results.getClosestCollision().getContactPoint();
}
return surfaceLocation;
}
}
