为什么宇宙飞船没有出现？

Question

我使用了jmonkeyengine，我从blendswap下载了一个宇宙飞船模型并将其转换为j3o，用jmonkeyengine加载它，用于空间场景，我可以控制船只并四处旅行。但是太空船没有加载。空间和行星出现了，但我希望宇宙飞船能够成为玩家控制的东西，而不是第一个像它一样的人。

我希望太空飞船出现是因为我加载它没有错误并将其添加到场景中但是stil没有显示。

//add saucer
ufoNode = (Node) assetManager
        .loadModel("usaucer_v01.j3o");      
rootNode.attachChild(ufoNode);

我应该怎样做才能让宇宙飞船出现？该计划

public class PlanetSimpleTest extends SimpleApplication {

    private PlanetAppState planetAppState;
    private Geometry mark;
    private Node ufoNode;
    private GameCharControl ufoControl;
    Camera cam2;

    public static void main(String[] args){
        AppSettings settings = new AppSettings(true);
        settings.setResolution(1024,768);
        PlanetSimpleTest app = new PlanetSimpleTest();

        app.setSettings(settings);
        //app.showSettings = true;
        app.start();
    }

    @Override
    public void simpleInitApp() {
        // Only show severe errors in log
        java.util.logging.Logger.getLogger("com.jme3").setLevel(java.util.logging.Level.SEVERE);

        // Toggle mouse cursor
        inputManager.addMapping("TOGGLE_CURSOR", 
                new MouseButtonTrigger(MouseInput.BUTTON_LEFT),
                new KeyTrigger(KeyInput.KEY_SPACE));
        inputManager.addListener(actionListener, "TOGGLE_CURSOR"); 
        // Toggle wireframe
        inputManager.addMapping("TOGGLE_WIREFRAME", 
            new KeyTrigger(KeyInput.KEY_T));
        inputManager.addListener(actionListener, "TOGGLE_WIREFRAME");
        // Collision test
        inputManager.addMapping("COLLISION_TEST", 
            new MouseButtonTrigger(MouseInput.BUTTON_RIGHT));
        inputManager.addListener(actionListener, "COLLISION_TEST"); 

        // Setup camera

        // In orbit
        this.getCamera().setLocation(new Vector3f(0f, 0f, 180000f));

        // On surface
        //this.getCamera().setLocation(new Vector3f(-6657.5254f, 27401.822f, 57199.777f));
        //this.getCamera().lookAtDirection(new Vector3f(0.06276598f, 0.94458306f, -0.3222158f), Vector3f.UNIT_Y);

        // Add sun
        //PointLight sun = new PointLight();
        //sun.setPosition(new Vector3f(-100000f,0,180000f));
        DirectionalLight sun = new DirectionalLight();
        sun.setDirection(new Vector3f(-.1f, 0f, -1f));
        sun.setColor(new ColorRGBA(0.75f,0.75f,0.75f,1.0f));      
        rootNode.addLight(sun);

        // Add sky
        Node sceneNode = new Node("Scene");
        sceneNode.attachChild(Utility.createSkyBox(this.getAssetManager(), "Textures/blue-glow-1024.dds"));
        rootNode.attachChild(sceneNode);

        // Create collision test mark
        Sphere sphere = new Sphere(30, 30, 5f);
        mark = new Geometry("mark", sphere);
        Material mark_mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md");
        mark_mat.setColor("Color", ColorRGBA.Red);
        mark.setMaterial(mark_mat);

        // Add planet app state
        planetAppState = new PlanetAppState(rootNode, sun);
        stateManager.attach(planetAppState);

        // Add planet
        FractalDataSource planetDataSource = new FractalDataSource(4);
        planetDataSource.setHeightScale(900f);
        Planet planet = Utility.createEarthLikePlanet(getAssetManager(), 63710.0f, null, planetDataSource);
        planetAppState.addPlanet(planet);
        rootNode.attachChild(planet);

        // Add moon
        FractalDataSource moonDataSource = new FractalDataSource(5);
        moonDataSource.setHeightScale(300f);
        Planet moon = Utility.createMoonLikePlanet(getAssetManager(), 20000, moonDataSource);
        planetAppState.addPlanet(moon);
        rootNode.attachChild(moon);
        moon.setLocalTranslation(-150000f, 0f, 0f);

        //add saucer
        ufoNode = (Node) assetManager
                .loadModel("usaucer_v01.j3o");
        ufoNode.setLocalScale(100f);
        rootNode.attachChild(ufoNode);

    }

    @Override
    public void simpleUpdate(float tpf) {        
        // slow camera down as we approach a planet
        Planet planet = planetAppState.getNearestPlanet();
        if (planet != null && planet.getPlanetToCamera() != null) {
            this.getFlyByCamera().setMoveSpeed(
                    FastMath.clamp(planet.getDistanceToCamera(), 100, 100000));
        }     
    }

    private ActionListener actionListener = new ActionListener(){
        public void onAction(String name, boolean pressed, float tpf){     
            if (name.equals("TOGGLE_CURSOR") && !pressed) {
                if (inputManager.isCursorVisible()) {
                    inputManager.setCursorVisible(false);
                } else {
                    inputManager.setCursorVisible(true);
                }
            }
            if (name.equals("TOGGLE_WIREFRAME") && !pressed) {
                for (Planet planet: planetAppState.getPlanets()) {
                    planet.toogleWireframe();
                }
            }
            if (name.equals("COLLISION_TEST") && !pressed) {
                CollisionResults results = new CollisionResults();
                Ray ray = new Ray(cam.getLocation(), cam.getDirection());

                // Test collision with closest planet's terrain only
                planetAppState.getNearestPlanet().getTerrainNode().collideWith(ray, results);

                System.out.println("----- Collisions? " + results.size() + "-----");
                for (int i = 0; i < results.size(); i++) {
                  // For each hit, we know distance, impact point, name of geometry.
                  float dist = results.getCollision(i).getDistance();
                  Vector3f pt = results.getCollision(i).getContactPoint();
                  String hit = results.getCollision(i).getGeometry().getName();
                  System.out.println("* Collision #" + i);
                  System.out.println("  You shot " + hit + " at " + pt + ", " + dist + " wu away.");
                }

                if (results.size() > 0) {
                  // The closest collision point is what was truly hit:
                  CollisionResult closest = results.getClosestCollision();
                  // Let's interact - we mark the hit with a red dot.
                  mark.setLocalTranslation(closest.getContactPoint());
                  rootNode.attachChild(mark);
                } else {
                  // No hits? Then remove the red mark.
                  rootNode.detachChild(mark);
                }
            }  
        }
    }; 

}

我从here获得的太空船并转换为jme3：s二进制格式j3o并添加到游戏中，但我显然没有尽一切努力让它出现在场景中。我已经在jmonkeyengine IDE中实现了这一点，但是当我在Eclipse中加载它时它不起作用所以我试图首先使用jmonkeyengine IDE创建场景。

然后我尝试用太空船创建一个场景，但我在JME SDK中得到了一个例外。

添加行

ufoNode.setLocalScale(300f);
ufoNode.setLocalTranslation((new Vector3f(10f, 10f, 180010f)));

宇宙飞船确实出现但可能并不完美。可以改进吗？

更新140104 17:54 CET

宇宙飞船似乎是倒置的（？）所以我现在已经旋转了。

//add saucer
ufoNode = (Node) assetManager.loadModel("usaucer_v01.j3o");
ufoNode.setLocalScale(1000f);
ufoNode.setLocalTranslation((new Vector3f(10f, 10f, 165000f)));

/* This quaternion stores a 180 degree rolling rotation */ 
Quaternion roll180 = new Quaternion(); 
roll180.fromAngleAxis(FastMath.PI , new Vector3f(0,0,1)); 
/* The rotation is applied: The object rolls by 180 degrees. */ 
ufoNode.setLocalRotation(roll180);      
rootNode.attachChild(ufoNode);  

Answer 1

您在0,0,0处添加太空船（因为您不移动它），但已将相机移至0f, 0f, 180000f。很可能它不会被击中或太小而无法看到。

尝试在jME SDK中加载太空船，并使用场景编辑器确认它在引擎内是否有效。

如果有效，那么尝试一个简单的测试场景，只需将宇宙飞船和摄像机放入 - 然后一旦有效，就一步一步向你想要的设置移动。