AI does not recognize hill

Troubleshooting ai
1

Hello,
I just want to add a simple AI that moves to a certain point and avoids the obstacles in the way. The only obstacles are so far hills in the terrain (made in the SDK). This is the code:
[java]package mygame;

import com.jme3.ai.navmesh.NavMesh;
import com.jme3.ai.navmesh.NavMeshPathfinder;
import com.jme3.ai.navmesh.Path.Waypoint;
import com.jme3.app.SimpleApplication;
import com.jme3.audio.AudioNode;
import com.jme3.bullet.BulletAppState;
import com.jme3.bullet.control.BetterCharacterControl;
import com.jme3.bullet.control.RigidBodyControl;
import com.jme3.input.KeyInput;
import com.jme3.input.controls.ActionListener;
import com.jme3.input.controls.KeyTrigger;
import com.jme3.light.DirectionalLight;
import com.jme3.math.ColorRGBA;
import com.jme3.math.Vector3f;
import com.jme3.renderer.RenderManager;
import com.jme3.scene.Geometry;
import com.jme3.scene.Mesh;
import com.jme3.scene.Node;
import com.jme3.scene.Spatial;

/**

  • test

  • @author normenhansen
    */
    public class Main extends SimpleApplication {

    private BulletAppState bulletAppState;
    private Spatial enemy;
    private BetterCharacterControl enemyControl;
    private NavMeshPathfinder navi;

    public static void main(String[] args) {
    Main app = new Main();
    app.start();
    }

    @Override
    public void simpleInitApp() {
    flyCam.setMoveSpeed(100f);
    cam.setLocation(new Vector3f(0f,50f,0f));
    bulletAppState = new BulletAppState();

     stateManager.attach(bulletAppState);
 bulletAppState.setDebugEnabled(true);
 initTerrain();
 initLight();
 initEnemy();

    }

    private void initTerrain() {
    Spatial terrain = assetManager.loadModel(“Scenes/Scene.j3o”);
    RigidBodyControl terrainControl = new RigidBodyControl(0f);
    terrain.addControl(terrainControl);
    bulletAppState.getPhysicsSpace().add(terrainControl);
    rootNode.attachChild(terrain);
    Node n = (Node) terrain;
    Geometry geom = (Geometry) n.getChild(“NavMesh”);
    Mesh mesh = geom.getMesh();
    System.out.println(geom.getName());
    NavMesh navMesh = new NavMesh(mesh);
    navi = new NavMeshPathfinder(navMesh);
    }

    private void initLight() {
    /**
    * A white, directional light source
    */
    DirectionalLight sun = new DirectionalLight();
    sun.setDirection((new Vector3f(-0.5f, -2f, -0.5f)).normalizeLocal());
    sun.setColor(ColorRGBA.White);
    rootNode.addLight(sun);
    }

    private void initEnemy() {
    enemy = assetManager.loadModel(“Models/skeleton.j3o”);
    enemyControl = new BetterCharacterControl(0.5f, 4f, 70f);
    enemy.addControl(enemyControl);
    bulletAppState.getPhysicsSpace().add(enemyControl);
    enemyControl.warp(new Vector3f(0f, 0f, -80f));
    //enemyControl.setGravity(new Vector3f(0f, -30f, 0f));
    rootNode.attachChild(enemy);
    navi.setPosition(enemy.getLocalTranslation());

    /* Spatial obstacle = assetManager.loadModel("Models/skeleton.j3o");
 BetterCharacterControl obstacleControl = new BetterCharacterControl(1f,4f,50f);
 obstacle.addControl(obstacleControl);
 bulletAppState.getPhysicsSpace().add(obstacleControl);
 obstacleControl.warp(new Vector3f(0f, 3f, 20f));
 obstacleControl.setGravity(new Vector3f(0f, -50f, 0f));
 rootNode.attachChild(obstacle);*/
 
 navi.computePath(new Vector3f(0f, 0f, 0f));

    }

    @Override
    public void simpleUpdate(float tpf) {
    Waypoint wayPoint = navi.getNextWaypoint();
    if (wayPoint == null) {
    return;
    }
    Vector3f vector = wayPoint.getPosition().subtract(enemy.getLocalTranslation());
    if (!(vector.length() < 1)) {
    enemyControl.setWalkDirection(vector.normalizeLocal().multLocal(tpf * 500));
    } else {
    navi.goToNextWaypoint();
    }
    }

    @Override
    public void simpleRender(RenderManager rm) {
    //TODO: add render code
    }
    }
    [/java]

The problem is, that the enemy is moving towards the point with ignoring any hills and because a hill is in the way, it moves against it and gets stuck.It does not even try to get around it…

Any ideas?

2

Look at your navmesh when you create it (select it in the SceneExplorer) and adjust the values when you create it.

3

I’ve tried really many values now, the character is just walking towards the wall… But I noticed that there was somehow no mesh at my wall. Maybe this is a problem? Here is an image:

I tried to fix this but I didn’t manage it…

4

The hills on the right are marked as an area that the character can walk on. Probably because it doesn’t reach the maximum slope you enter in the settings.

5

Yeah sorry I forgot to add: The character is at the left side of the hills (left of the high hill) and I calculate the path to go between them. He walks in a straight line to the target position and gets of course blocked by the hill.

6

Well your loop drains the whole waypoint queue in a few frames… The character will go in the direction of waypoint 1 for one frame, then 2 for one frame etc. and then to the last waypoint for the rest of the time until it arrives.

1 Like
7

Thanks Normen! That was the problem. Another one was, that the position of the Spatial enemy was not the same as the Vector where I warped the BetterCharacterControl (after 1 frame or so the position got synchronized). So here is the Code that works for me:

[java]package mygame;

import com.jme3.ai.navmesh.NavMesh;
import com.jme3.ai.navmesh.NavMeshPathfinder;
import com.jme3.ai.navmesh.Path.Waypoint;
import com.jme3.app.SimpleApplication;
import com.jme3.bullet.BulletAppState;
import com.jme3.bullet.collision.shapes.BoxCollisionShape;
import com.jme3.bullet.control.BetterCharacterControl;
import com.jme3.bullet.control.RigidBodyControl;
import com.jme3.light.DirectionalLight;
import com.jme3.material.Material;
import com.jme3.math.ColorRGBA;
import com.jme3.math.Vector3f;
import com.jme3.renderer.RenderManager;
import com.jme3.scene.Geometry;
import com.jme3.scene.Mesh;
import com.jme3.scene.Node;
import com.jme3.scene.Spatial;
import com.jme3.scene.shape.Box;

/**

  • test

  • @author normenhansen
    */
    public class Main extends SimpleApplication {

    private BulletAppState bulletAppState;
    private Spatial enemy;
    private BetterCharacterControl enemyControl;
    private NavMeshPathfinder navi;

    public static void main(String[] args) {
    Main app = new Main();
    app.start();
    }

    @Override
    public void simpleInitApp() {
    flyCam.setMoveSpeed(100f);
    cam.setLocation(new Vector3f(0f, 50f, 0f));
    bulletAppState = new BulletAppState();

     stateManager.attach(bulletAppState);
 bulletAppState.setDebugEnabled(true);
 initTerrain();
 initLight();
 initEnemy();

    }

    private void initTerrain() {
    Spatial terrain = assetManager.loadModel(“Scenes/Scene.j3o”);
    RigidBodyControl terrainControl = new RigidBodyControl(0f);
    terrain.addControl(terrainControl);
    bulletAppState.getPhysicsSpace().add(terrainControl);
    rootNode.attachChild(terrain);
    Node n = (Node) terrain;
    Geometry geom = (Geometry) n.getChild(“NavMesh”);
    Mesh mesh = geom.getMesh();
    NavMesh navMesh = new NavMesh(mesh);
    navi = new NavMeshPathfinder(navMesh);
    }

    private void initLight() {
    /**
    * A white, directional light source
    */
    DirectionalLight sun = new DirectionalLight();
    sun.setDirection((new Vector3f(-0.5f, -2f, -0.5f)).normalizeLocal());
    sun.setColor(ColorRGBA.White);
    rootNode.addLight(sun);
    }

    private void initEnemy() {
    enemy = assetManager.loadModel(“Models/skeleton.j3o”);
    enemyControl = new BetterCharacterControl(1f, 4f, 70f);
    enemy.addControl(enemyControl);
    bulletAppState.getPhysicsSpace().add(enemyControl);
    enemyControl.warp(new Vector3f(0f, 0f, -80f));
    enemyControl.setGravity(new Vector3f(0f, -30f, 0f));
    rootNode.attachChild(enemy);
    navi.setPosition(new Vector3f(0f, 0f, -80f)); //Here the position of the Spatial is not the same as the position I warped the Control to

      new Thread(new Runnable() {
      @Override
      public void run() {
          navi.computePath(new Vector3f(0f, 0f, 0));
      }
  }).start();
 //showWaypoints();

    }

    private void showWaypoints() {
    Material mat = new Material(assetManager, “Common/MatDefs/Misc/Unshaded.j3md”);
    mat.setColor(“Color”, ColorRGBA.Red);

     for (Waypoint w : navi.getPath().getWaypoints()) {
     Box b = new Box(1, 1, 1);
     Geometry geom = new Geometry("Box", b);

     geom.setMaterial(mat);

     geom.setLocalTranslation(w.getPosition().addLocal(new Vector3f(0f, 0f, 0f)));
     rootNode.attachChild(geom);
 }

    }

    @Override
    public void simpleUpdate(float tpf) {
    Waypoint wayPoint = navi.getNextWaypoint();
    if (wayPoint == null) {
    return;
    }

     Vector3f v = wayPoint.getPosition().subtract(enemy.getLocalTranslation());
 enemyControl.setWalkDirection(v.normalize().mult(10f));
 if(enemy.getLocalTranslation().distance(wayPoint.getPosition()) &lt;= 0.5f &amp;&amp; !navi.getPath().getEnd().equals(wayPoint)) {  //.equals() does not work because the position is     never exactly the same
     navi.goToNextWaypoint();
 }

    }

    @Override
    public void simpleRender(RenderManager rm) {
    //TODO: add render code
    }
    }
    [/java]