Question

我已经尝试了下面的代码，但是我在下面突出显示的行中得到了NullPointerException。

班级名称：地形

在以下行中获取例外

 modelInstance = new ModelInstance(modelBuilder.end(),0,0,0);

请找到以下代码

代码：

private PerspectiveCamera camera;
    private ModelBatch modelBatch;
    private ModelBuilder modelBuilder;
    private Model box;
    private ModelInstance modelInstance;
    private Environment environment;

   @Override
   public void create () {

        camera = new PerspectiveCamera(75,Gdx.graphics.getWidth(),Gdx.graphics.getHeight());
        camera.position.set(0f, 0f, 3f);
        camera.lookAt(0f,0f,0f);
        camera.near =0.1f;
        camera.far = 300f;

        modelBatch = new ModelBatch();
        modelBuilder = new ModelBuilder();

        modelBuilder.begin();
        MeshPartBuilder part=modelBuilder.part("Box1", GL20.GL_TRIANGLES, Usage.Position, null);
        part.rect(new Vector3(0,0,0),new Vector3(100,0,0),new Vector3(100,100,0),new Vector3(0,100,0),new Vector3(0,0,0));
        modelInstance = new ModelInstance(modelBuilder.end(),0,0,0);
        environment = new Environment();
        environment.set(new ColorAttribute(ColorAttribute.AmbientLight,0.8f,0.8f,0.8f,1f));

        Gdx.input.setInputProcessor(this);

   }

   @Override
   public void render () {
      Gdx.gl.glClearColor(0, 0, 0, 1);
      Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT|GL20.GL_DEPTH_BUFFER_BIT);

        camera.update();
        modelBatch.begin(camera);
        modelBatch.render(modelInstance,environment);
        modelBatch.end();
   }

    @Override
    public boolean keyDown(int keycode) {
        // In the real world, do not create NEW variables over and over, create
        // a temporary static member instead
        if(keycode == Input.Keys.LEFT)
            camera.rotateAround(new Vector3(0f, 0f, 0f), new Vector3(0f, 1f, 0f), 1f);
        if(keycode == Input.Keys.RIGHT)
            camera.rotateAround(new Vector3(0f,0f,0f),new Vector3(0f,1f,0f), -1f);
        return true;
    }

当我尝试执行上面的代码时，我收到以下错误。

线程“LWJGL Application”中的异常java.lang.NullPointerException 在com.badlogic.gdx.graphics.g3d.ModelInstance.invalidate（ModelInstance.java:269）在com.badlogic.gdx.graphics.g3d.ModelInstance.invalidate（ModelInstance.java:283）在com.badlogic.gdx.graphics.g3d.ModelInstance.copyNodes（ModelInstance.java:226）在com.badlogic.gdx.graphics.g3d.ModelInstance。（ModelInstance.java:154）在com.badlogic.gdx.graphics.g3d.ModelInstance。（ModelInstance.java:146）在com.badlogic.gdx.graphics.g3d.ModelInstance。（ModelInstance.java:62）在com.badlogic.gdx.graphics.g3d.ModelInstance。（ModelInstance.java:188）在com.mygdx.game.desktop.Terrain.create（Terrain.java:63）在com.badlogic.gdx.backends.lwjgl.LwjglApplication.mainLoop（LwjglApplication.java:147）在com.badlogic.gdx.backends.lwjgl.LwjglApplication $ 1.run（LwjglApplication.java:124）

有人可以提供解决方案以使代码有效。

LibGDX 3d在ModelInstance中获取空指针异常

0 个答案: