Question

我有两个模型实例modelInstance1和modelInstance2。

modelInstance1 - position Vector3(0,0,0)
modelInstance2 - position Vector3(10,10,10)

如何将modelInstance1旋转到modelInstance2并在update方法中移动此方向？

回答后的问题：

我试过回答基本的xoppa的立方体教程并且有些不好。有什么问题吗？

@Override
public void create() {
    environment = new Environment();
    environment.set(new ColorAttribute(ColorAttribute.AmbientLight, 0.4f, 0.4f, 0.4f, 1f));
    environment.add(new DirectionalLight().set(0.8f, 0.8f, 0.8f, -1f, -0.8f, -0.2f));

    modelBatch = new ModelBatch();

    cam = new PerspectiveCamera(67, Gdx.graphics.getWidth(), Gdx.graphics.getHeight());
    cam.position.set(10f, 10f, 10f);
    cam.lookAt(0,0,0);
    cam.near = 1f;
    cam.far = 300f;
    cam.update();

    ModelBuilder modelBuilder = new ModelBuilder();
    model = modelBuilder.createBox(5f, 5f, 10f, 
        new Material(ColorAttribute.createDiffuse(Color.GREEN)),
        Usage.Position | Usage.Normal);

    instance1 = new ModelInstance(model);
    instance2 = new ModelInstance(model);

    instance2.transform.translate(10,0,10);

    camController = new CameraInputController(cam);
    Gdx.input.setInputProcessor(camController);
}

渲染和更新方法。

@Override
public void render() {

    Vector3 position1 = new Vector3(), position2 = new Vector3(), direction = new Vector3();

    instance1.transform.getTranslation(position1);
    instance2.transform.getTranslation(position2);
    direction = (position2).sub(position1).nor();

    instance1.transform.setToRotation(direction, Vector3.X);

instance2.transform.translate(0.05f, 0, 0.05f).rotate(0, 1, 0, 10*Gdx.graphics.getDeltaTime()).translate(0, 0, 0);


    camController.update();

    Gdx.gl.glViewport(0, 0, Gdx.graphics.getWidth(), Gdx.graphics.getHeight());
    Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT | GL20.GL_DEPTH_BUFFER_BIT);

    modelBatch.begin(cam);
    modelBatch.render(instance1, environment);
    modelBatch.render(instance2, environment);
    modelBatch.end();
}

我尝试将setToRotate方法更改为：

instance1.transform.setToLookAt(position1, position2, new Vector3(0,1,0));

但同样的问题..

Answer 1

在伪代码中面对看起来像：

modelInstance1.direction(from matrix) = (modelInstance2.position).sub(modelInstance1.position).nor();
modelInstance1.setRotation(modelInstance1.direction, Vector3.Y);

更新：在此示例中，方向向量应用于对象的Vector3.Y轴。你的场景可以有另一个轴系统，所以有时你需要尝试不同的物体轴来找到目标轴。

Answer 2

终于....就是这样!!!!!!!!!!!!!!!!!!

当有人知道同样的代码做得更好时，请告诉我。

我希望能帮助别人。：）

    Vector3 position1 = new Vector3(), position2 = new Vector3(), direction = new Vector3();

    instance2.transform.translate(0.5f, 0, 0.5f).rotate(0, 1, 0, 45*Gdx.graphics.getDeltaTime()).translate(0, 0, 0);

    instance1.transform.getTranslation(position1);
    instance2.transform.getTranslation(position2);
    direction = (position2).sub(position1).nor();

    direction.set(-direction.x, -direction.y, -direction.z);

    Quaternion quaternion = new Quaternion();
    Matrix4 instanceRotation = instance1.transform.cpy().mul(instance1transform);

    instanceRotation.setToLookAt(direction, new Vector3(0,-1,0));
    instanceRotation.rotate(0, 0, 1, 180);
    instanceRotation.getRotation(quaternion);

    instance1.transform.set(position1, quaternion);

libGDX 3D跟随和面对对象

2 个答案: