java - 快速移动鼠标时相机有时会倒置

Question

我正在尝试在 LibGDX 中使用 3D，但是相机会倒置，而我所做的任何事情似乎都无法阻止它发生的原因，但原因不明。

我已经单独测试了每个旋转轴，它工作得很好，但是当它们一起使用时，它有时会颠倒过来。

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, -2.5f, -5, -10));

    modelBatch = new ModelBatch();

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

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

    instance = new ModelInstance(model);

    instance.transform.translate(-10, -10, -10);

    Gdx.input.setCursorCatched(true);
    Gdx.input.setCursorPosition(Gdx.graphics.getWidth() / 2, Gdx.graphics.getHeight() / 2);
}

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

    isup = false;
    ispressed = false;
    Vector3 direction = cam.direction.cpy();

    Vector3 crossProduct = new Vector3(); //CROSSPRODUCT OF PLAYER DIRECTION AGAINST Y AXIS
    crossProduct.x = -direction.z;
    crossProduct.y = 0;
    crossProduct.z = direction.x;

    differencey = -Gdx.input.getY() + (Gdx.graphics.getHeight() / 2);
    if ((cam.direction.y > -0.8 || differencey > 0) && (cam.direction.y < 0.8 || differencey < 0)) {
        if (differencey > 50) {
            differencey = 50;
        }
        cam.rotate(crossProduct, differencey / 10);

        cam.update();
    }

    differencex = Gdx.input.getX() - (Gdx.graphics.getWidth() / 2);

    cam.rotate(new Vector3(0, -1, 0), differencex / 10);

    cam.update();

    modelBatch.begin(cam);
    modelBatch.render(instance, environment);
    modelBatch.end();

    Gdx.input.setCursorPosition(Gdx.graphics.getWidth() / 2, Gdx.graphics.getHeight() / 2);

    if (Gdx.input.isKeyPressed(Keys.ESCAPE)) {
        Gdx.app.exit();
    }

相机的移动应该受到限制，以便如果用户分别几乎是直视向上或直下，则相机不能进一步向上或向下移动，但是相机有时会移动超过这个限制。

标签： java3dcameralibgdx