贴花不会随着相机移动而旋转

Question

我正在尝试使用贴花作为广告牌。贴花似乎被涂好了但是当我移动相机时，贴花似乎是静态的，并且不会转向面对相机。这是我的代码

void create() {
            float w = Gdx.graphics.getWidth();
        float h = Gdx.graphics.getHeight();

            camera = new PerspectiveCamera(75, 10, 10*h/w);

        camera.position.set(2.5f,2.5f,5);
        camera.direction.set(-1, -1, -1);
        camera.up.set(0,1,0);

        camera.near = GameConfig.getInstance().camera.wiew_distance_near;
        camera.far = GameConfig.getInstance().camera.view_distance_far;

                // load textures
        plant = Decal.newDecal(1,1,new TextureRegion(textureTree),true);
        plant2 = Decal.newDecal(1,1,new TextureRegion(textureTree),true);
        plant3 = Decal.newDecal(1,1,new TextureRegion(textureTree),true);

        plant.setPosition(1, 2, 0);
        plant2.setPosition(3, 5, 0);
        plant3.setPosition(5, 5, 0);

        decalBatch = new DecalBatch();

        for(int z = 0; z < 10; z++) {
            for(int x = 0; x < 10; x++) {
                sprites[x][z] = new Sprite(texture);
                sprites[x][z].setPosition(x,z);
                sprites[x][z].setSize(1, 1);
            }
        }
        matrix.setToRotation(new Vector3(1, 0, 0), 90);

}

render() {
            Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
        controller.update(Gdx.graphics.getDeltaTime());

        camera.update();    
        batch.begin();

        batch.setProjectionMatrix(camera.combined);
        batch.setTransformMatrix(matrix);

        for(int z = 0; z < 10; z++) {
            for(int x = 0; x < 10; x++) {
                sprites[x][z].draw(batch);
            }
        }


        batch.end();
        updateDecals();

        // decals
        decalBatch.add(plant);
        decalBatch.add(plant2);
        decalBatch.add(plant3);

        decalBatch.flush();

                Matrix4 viewMatrix = new Matrix4();
                viewMatrix.setToOrtho2D(0, 0, VIEWPORT_WIDTH, VIEWPORT_HEIGHT);
        UIbatch.setProjectionMatrix(viewMatrix);
        UIbatch.begin();

        renderUI(UIbatch);
        UIbatch.end();

}

void updateDecals() {
                plant.lookAt(camera.position.cpy(), new Vector3(0,0,-1));
        plant2.lookAt(camera.position.cpy(), new Vector3(0,0,-1));
        plant3.lookAt(camera.position.cpy(), new Vector3(0,0,-1));
}

我认为问题出在前一轮旋转以绘制瓷砖地板，但贴花批次无法旋转。