如何使用AR Core将多个3D对象组合成一个？

Question

我在场景中展示了多个3D物体（请查看下面图片）

我有3个3D模型，现在是否可以将它们分组？例如，如果我移动一个3D物体，则其他2个3D物体也需要移动。是否可以在不使用Unity和云锚的情况下实现这一点？

以下是我的代码：

package com.google.ar.sceneform.samples.hellosceneform;

import android.app.Activity;
import android.app.ActivityManager;
import android.content.Context;
import android.os.Build;
import android.os.Build.VERSION_CODES;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.Gravity;
import android.view.MotionEvent;
import android.widget.Toast;
import com.google.ar.core.Anchor;

import com.google.ar.core.HitResult;
import com.google.ar.core.Plane;
import com.google.ar.sceneform.AnchorNode;
import com.google.ar.sceneform.rendering.ModelRenderable;
import com.google.ar.sceneform.ux.ArFragment;
import com.google.ar.sceneform.ux.TransformableNode;


public class HelloSceneformActivity extends AppCompatActivity {
  private static final String TAG = HelloSceneformActivity.class.getSimpleName();
  private static final double MIN_OPENGL_VERSION = 3.0;

  private ArFragment arFragment;
  private ModelRenderable andyRenderable;

  @Override
  @SuppressWarnings({"AndroidApiChecker", "FutureReturnValueIgnored"})

  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    if (!checkIsSupportedDeviceOrFinish(this)) {
      return;
    }

    setContentView(R.layout.activity_ux);
    arFragment = (ArFragment) getSupportFragmentManager().findFragmentById(R.id.ux_fragment);

    // When you build a Renderable, Sceneform loads its resources in the background while returning
    // a CompletableFuture. Call thenAccept(), handle(), or check isDone() before calling get().
    ModelRenderable.builder()
        .setSource(this, R.raw.andy)
        .build()
        .thenAccept(renderable -> andyRenderable = renderable)
        .exceptionally(
            throwable -> {
              Toast toast =
                  Toast.makeText(this, "Unable to load andy renderable", Toast.LENGTH_LONG);
              toast.setGravity(Gravity.CENTER, 0, 0);
              toast.show();
              return null;
            });

    arFragment.setOnTapArPlaneListener(
        (HitResult hitResult, Plane plane, MotionEvent motionEvent) -> {
          if (andyRenderable == null) {
            return;
          }

          // Create the Anchor.
          Anchor anchor = hitResult.createAnchor();
          AnchorNode anchorNode = new AnchorNode(anchor);
          anchorNode.setParent(arFragment.getArSceneView().getScene());

          // Create the transformable andy and add it to the anchor.
          TransformableNode andy = new TransformableNode(arFragment.getTransformationSystem());
          andy.setParent(anchorNode);
          andy.setRenderable(andyRenderable);
          andy.select();
        });
  }


  public static boolean checkIsSupportedDeviceOrFinish(final Activity activity) {
    if (Build.VERSION.SDK_INT < VERSION_CODES.N) {
      Log.e(TAG, "Sceneform requires Android N or later");
      Toast.makeText(activity, "Sceneform requires Android N or later", Toast.LENGTH_LONG).show();
      activity.finish();
      return false;
    }
    String openGlVersionString =
        ((ActivityManager) activity.getSystemService(Context.ACTIVITY_SERVICE))
            .getDeviceConfigurationInfo()
            .getGlEsVersion();
    if (Double.parseDouble(openGlVersionString) < MIN_OPENGL_VERSION) {
      Log.e(TAG, "Sceneform requires OpenGL ES 3.0 later");
      Toast.makeText(activity, "Sceneform requires OpenGL ES 3.0 or later", Toast.LENGTH_LONG)
          .show();
      activity.finish();
      return false;
    }
    return true;
  }
}

- Madpop

Answer 1

你可以自己对节点进行分组，并在移动其中一个节点时，通过将相同的变换应用于每个节点来移动该组中的每个节点。

高级别上说，为你的节点创建一个组、数组或某种集合，无论哪种方式适用于你的应用程序。

然后，当你想要移动该组时，可以循环遍历每个节点，并为每个节点应用相同的变换 - 例如，在下面的示例中，所有节点都将应用平移(-0.05f,0,0)：

        //Looping over each node in your group
        {
             //For each node, get the current Pose and transform it then set a new anchor at the new pose
             Session session = arFragment.getArSceneView().getSession();
             Anchor nextAnchor = [Get the next anchor node in your array or group]
             Pose oldPose = nextAnchor.getPose();
             Pose newPose = oldPose.compose(Pose.makeTranslation(-0.05f,0,0));
             movedAnchor = moveRenderable(currentSelectedAnchorNode, newPose);
             [Update your array or collection or group with this 'new' movedAnchor]
        }

要实际移动各个节点，可以使用以下代码。这实际上删除了当前位置的节点并在目标位置重新创建了新节点：

private AnchorNode moveRenderable(AnchorNode anchorNodeToMove, Pose newPoseToMoveTo) {
        //Move a renderable to a new pose
        if (anchorNodeToMove != null) {
            arFragment.getArSceneView().getScene().removeChild(anchorNodeToMove);
        } else {
            Log.d(TAG,"moveRenderable - anchorNodeToMove was null");
            return null;
        }
        Frame frame = arFragment.getArSceneView().getArFrame();
        Session session = arFragment.getArSceneView().getSession();
        Anchor markAnchor = session.createAnchor(newPoseToMoveTo.extractTranslation());
        AnchorNode newAnchorNode = new AnchorNode(markAnchor);
        newAnchorNode.setRenderable(andyRenderable);
        newAnchorNode.setParent(arFragment.getArSceneView().getScene());

        return newAnchorNode;
    }

- Mick

Answer 2

你可以使用.setParent()方法将3D对象分组。当一个对象被转换（移动、旋转或缩放）时，子对象也会被转换。

太阳系示例在createSolarSystem()中演示了这一点。行星成为太阳的子项，而月球则成为地球节点的子项。

然后，您可以使用setLocalPosition()相对于父对象定位该对象。例如在太阳活动中定位行星:

Planet planet =
    new Planet(
        this, name, planetScale, orbitDegreesPerSecond, axisTilt, renderable, solarSettings);
planet.setParent(orbit);
planet.setLocalPosition(new Vector3(auFromParent * AU_TO_METERS, 0.0f, 0.0f));

- Clayton Wilkinson

Answer 3

你可以通过获取所有TransformableNode节点的当前位置来实现此操作。

然后，像这样为所有节点分配新的向量值：node1.setLocalPosition(localPosition);

    private void modleMovement(TransformableNode node, String moveMent) {
            Vector3 currentPosition1 = new Vector3();
            Vector3 currentPosition2 = new Vector3();
            Vector3 currentPosition3 = new Vector3();
            Vector3 move = new Vector3();

            currentPosition1 =Objects.requireNonNull( node1.getLocalPosition());
            currentPosition2 =Objects.requireNonNull( node2.getLocalPosition());
            currentPosition3 =Objects.requireNonNull( node3.getLocalPosition());

            if (moveMent.equals("down")) {
                move.set(currentPosition.x, (float) (currentPosition.y - 0.1), currentPosition.z);
                localPosition = move;
            }

            if (moveMent.equals("up")) {
                move.set(currentPosition.x, (float) (currentPosition.y + 0.1), currentPosition.z);
                localPosition = move;
            }

     node1.setLocalPosition(localPosition);
    }

- Bilz