libgdx如何在触摸时缩放和旋转3d模型

Question

我正在尝试创建一个简单的应用程序,它允许您从.obj加载3D模型,并通过触摸屏幕缩放/旋转它.

我设法编写了从文件中加载3d模型并检测手势的代码,但现在我不知道如何通过触摸屏幕来启用缩放/旋转功能.

这是我现在的代码:

public class RenderObjApp implements ApplicationListener, GestureDetector.GestureListener {
    public static int SCREEN_WIDTH = 800;
    public static int SCREEN_HEIGHT = 600;

    private static final String TAG = RenderObjApp.class.getSimpleName();

    private Mesh model;
    private PerspectiveCamera camera;

    private float scale = 1f;

    @Override
    public void create() {
        model = ObjLoader.loadObj(Gdx.files.internal("data/cessna.obj").read(), true);
        Gdx.gl.glEnable(GL10.GL_DEPTH_TEST);
        Gdx.input.setInputProcessor(new GestureDetector(this));
    }

    @Override
    public void dispose() {
    }

    @Override
    public void pause() {
    }


    @Override
    public void render() {
        Gdx.gl.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
        Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
        camera.update();
        camera.apply(Gdx.gl10);
        model.render(GL10.GL_TRIANGLES);
    }

    @Override
    public void resize(int arg0, int arg1) {
        float aspectRatio = (float) arg0 / (float) arg1;
        camera = new PerspectiveCamera(75, 2f * aspectRatio, 2f);
        camera.near = 0.1f;
        camera.translate(0, 0, 0);
    }

    @Override
    public void resume() {
    }

    @Override
    public boolean touchDown(float x, float y, int pointer) {
        Gdx.app.log(TAG, "touchDown: ");
        return false;
    }

    @Override
    public boolean tap(float x, float y, int count, int pointer, int button) {
        Gdx.app.log(TAG, "tap: ");   
        return false;
    }

    @Override
    public boolean longPress(float x, float y) {
        Gdx.app.log(TAG, "zoom: ");
        return false;
    }

    @Override
    public boolean fling(float velocityX, float velocityY, int pointer, int button) {
        Gdx.app.log(TAG, "fling: ");
        return false;
    }

    @Override
    public boolean pan(float x, float y, float deltaX, float deltaY) {
        Gdx.app.log(TAG, "pan: ");
        return false;
    }

    @Override
    public boolean zoom(float initialDistance, float distance) {
        Gdx.app.log(TAG, "zoom: initialDistance=" + initialDistance + ", distance=" + distance);
        return false;
    }

    @Override
    public boolean pinch(Vector2 initialPointer1, Vector2 initialPointer2, Vector2 pointer1, Vector2 pointer2) {
        Gdx.app.log(TAG, "pinch: ");
        return false;
    }
}

所以我正在寻找如何旋转PerspectiveCamera和Mesh本身.

Answer 1

您要么需要旋转相机，要么旋转模型。

我相信 libGDX Camera.rotateAround方法可以满足您的需要。将“点”保留为模型的中心，并根据用户滑动/平移的方式设置“轴”参数。“角度”可以是固定值，也可以是相对于猛击/平移的强度。