ARCoreで３Dオブジェクト2

#3Dオブジェクトの配置、大きさ、向きを調整する。

##ユーザーの前0.5メートルの位置を見つけます。
カメラの位置に対してアンカーの位置を設定します。
  SceneView sceneView = arFragment.getArSceneView();
                        Vector3 cameraPos = sceneView.getScene().getCamera().getWorldPosition();
                        Vector3 cameraForward = sceneView.getScene().getCamera().getForward();
                        Vector3 position = Vector3.add(cameraPos, cameraForward.scaled(0.5f));
##大きさを調整
model.getScaleController().setMinScale(0.01f);
model.getScaleController().setMaxScale(2.0f);
model.setLocalScale(new Vector3(0.5f,0f,0.5f));
##向きを調整
y軸（縦軸）　を中心に１８０度回転
model.setLocalRotation(Quaternion.axisAngle(new Vector3(0,1,0),-120));

```
public class MainActivity extends AppCompatActivity {
    private static final int CAMERA_PERMISSION_CODE = 0;
    private static final String CAMERA_PERMISSION = Manifest.permission.CAMERA;
    private ModelRenderable modelRenderable;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ArFragment arFragment = (ArFragment) getSupportFragmentManager().findFragmentById(R.id.ar_fragment);
        ModelRenderable.builder()
                .setSource(this, R.raw.ball)
                .build()
                .thenAccept(renderable -> modelRenderable = renderable)
                .exceptionally(
                        throwable -> {
                            Toast toast =
                                    Toast.makeText(this, "読み込み失敗", Toast.LENGTH_LONG);
                            toast.setGravity(Gravity.CENTER, 0, 0);
                            toast.show();
                            return null;
                        });
         if(arFragment != null ) {

            arFragment.setOnTapArPlaneListener(
                    (HitResult hitResult, Plane plane, MotionEvent motionEvent) -> {

                        if (modelRenderable == null) {
                            return;
                        }
                        //ユーザーの前0.5メートルの位置を見つけます。
                        Session session = arFragment.getArSceneView().getSession();
                        SceneView sceneView = arFragment.getArSceneView();
                        Vector3 cameraPos = sceneView.getScene().getCamera().getWorldPosition();
                        Vector3 cameraForward = sceneView.getScene().getCamera().getForward();
                        Vector3 position = Vector3.add(cameraPos, cameraForward.scaled(0.5f));
                        Pose pose = Pose.makeTranslation(position.x, position.y, position.z);
                        Anchor anchor = session.createAnchor(pose);

                        AnchorNode anchorNode = new AnchorNode(anchor);
                        anchorNode.setParent(arFragment.getArSceneView().getScene());
                        TransformableNode model = new TransformableNode(arFragment.getTransformationSystem());
                        model.setRenderable(modelRenderable);

                        //大きさを指定します。
                        model.getScaleController().setMinScale(0.01f);
                        model.getScaleController().setMaxScale(2.0f);
                        //v:width v1:? v2:height
                        model.setLocalScale(new Vector3(0.5f,0f,0.5f));
                        //y軸　縦軸　を中心に１８０度回転
                        model.setLocalRotation(Quaternion.axisAngle(new Vector3(0,1,0),-120));
                        model.setParent(anchorNode);
                        model.select();
                        
                    });
        }
    }
    @Override
    protected void onResume() {
        super.onResume();

        if (ContextCompat.checkSelfPermission(this, CAMERA_PERMISSION) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[] {CAMERA_PERMISSION}, CAMERA_PERMISSION_CODE);
        }
    }
}
```