ARCore 相机似乎不支持拍照。 https://developers.google.com/ar/reference/java/com/google/ar/core/Camera

有人知道如何使用 ARCore 拍照吗？

最佳答案

我假设您指的是相机所见内容和 AR 对象的图片。在高层次上，您需要获得写入外部存储的权限以保存图片，从 OpenGL 复制帧，然后将其保存为 png(例如)。以下是具体情况:

将WRITE_EXTERNAL_STORAGE权限添加到AndroidManifest.xml

   <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

然后更改 CameraPermissionHelper 以迭代 CAMERA 和 WRITE_EXTERNAL_STORAGE 权限以确保它们被授予

 private static final String REQUIRED_PERMISSIONS[] = {
          Manifest.permission.WRITE_EXTERNAL_STORAGE,
          Manifest.permission.CAMERA
  };

  /**
   * Check to see we have the necessary permissions for this app.
   */
  public static boolean hasCameraPermission(Activity activity) {
    for (String p : REQUIRED_PERMISSIONS) {
      if (ContextCompat.checkSelfPermission(activity, p) !=
            PackageManager.PERMISSION_GRANTED) {
        return false;
      }
    }
    return true;
  }

  /**
   * Check to see we have the necessary permissions for this app,
   *   and ask for them if we don't.
   */
  public static void requestCameraPermission(Activity activity) {
    ActivityCompat.requestPermissions(activity, REQUIRED_PERMISSIONS,
            CAMERA_PERMISSION_CODE);
  }

  /**
   * Check to see if we need to show the rationale for this permission.
   */
  public static boolean shouldShowRequestPermissionRationale(Activity activity) {
    for (String p : REQUIRED_PERMISSIONS) {
      if (ActivityCompat.shouldShowRequestPermissionRationale(activity, p)) {
        return true;
      }
    }
    return false;
  }

接下来，向 HelloARActivity 添加几个字段以跟踪框架的尺寸和 bool 值以指示何时保存图片。

 private int mWidth;
 private int mHeight;
 private  boolean capturePicture = false;

在onSurfaceChanged()中设置宽高

 public void onSurfaceChanged(GL10 gl, int width, int height) {
     mDisplayRotationHelper.onSurfaceChanged(width, height);
     GLES20.glViewport(0, 0, width, height);
     mWidth = width;
     mHeight = height;
 }

在 onDrawFrame() 的底部，添加对捕获标志的检查。这应该在所有其他绘图发生之后完成。

         if (capturePicture) {
             capturePicture = false;
             SavePicture();
         }

然后添加拍照按钮的onClick方法，以及保存图片的实际代码:

  public void onSavePicture(View view) {
    // Here just a set a flag so we can copy
    // the image from the onDrawFrame() method.
    // This is required for OpenGL so we are on the rendering thread.
    this.capturePicture = true;
  }

  /**
   * Call from the GLThread to save a picture of the current frame.
   */
  public void SavePicture() throws IOException {
    int pixelData[] = new int[mWidth * mHeight];

    // Read the pixels from the current GL frame.
    IntBuffer buf = IntBuffer.wrap(pixelData);
    buf.position(0);
    GLES20.glReadPixels(0, 0, mWidth, mHeight,
            GLES20.GL_RGBA, GLES20.GL_UNSIGNED_BYTE, buf);

    // Create a file in the Pictures/HelloAR album.
    final File out = new File(Environment.getExternalStoragePublicDirectory(
            Environment.DIRECTORY_PICTURES) + "/HelloAR", "Img" +
            Long.toHexString(System.currentTimeMillis()) + ".png");

    // Make sure the directory exists
    if (!out.getParentFile().exists()) {
      out.getParentFile().mkdirs();
    }

    // Convert the pixel data from RGBA to what Android wants, ARGB.
    int bitmapData[] = new int[pixelData.length];
    for (int i = 0; i < mHeight; i++) {
      for (int j = 0; j < mWidth; j++) {
        int p = pixelData[i * mWidth + j];
        int b = (p & 0x00ff0000) >> 16;
        int r = (p & 0x000000ff) << 16;
        int ga = p & 0xff00ff00;
        bitmapData[(mHeight - i - 1) * mWidth + j] = ga | r | b;
      }
    }
    // Create a bitmap.
    Bitmap bmp = Bitmap.createBitmap(bitmapData,
                     mWidth, mHeight, Bitmap.Config.ARGB_8888);

    // Write it to disk.
    FileOutputStream fos = new FileOutputStream(out);
    bmp.compress(Bitmap.CompressFormat.PNG, 100, fos);
    fos.flush();
    fos.close();
    runOnUiThread(new Runnable() {
      @Override
      public void run() {
        showSnackbarMessage("Wrote " + out.getName(), false);
      }
    });
  }

最后一步是将按钮添加到 activity_main.xml 布局的末尾

<Button
    android:id="@+id/fboRecord_button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignStart="@+id/surfaceview"
    android:layout_alignTop="@+id/surfaceview"
    android:onClick="onSavePicture"
    android:text="Snap"
    tools:ignore="OnClick"/>

关于android - 如何使用 ARCore 用相机拍照，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/48191513/