1
\$\begingroup\$

So I've tried the vector rotation sensor using the Android API and it works perfectly to do what I want, but LibGDX does not support this sensor. I've been searching and it seems like I can do the same thing as vector rotation sensor using the accelerometer and compass values returned by LibGDX API:

Gdx.input.getAccelerometerX();
Gdx.input.getAccelerometerY();
Gdx.input.getAccelerometerZ();

Gdx.input.getAzimuth();
Gdx.input.getPitch();
Gdx.input.getRoll();

But I couldn't find out how to do this.

\$\endgroup\$
1
\$\begingroup\$

You can get the rotation matrix by calling Gdx.input.getRotation(float[] matrix), it gives you the rotation matrix as per the Android SensorManager getRotationMatrix call (SensorManager.getRotationMatrix).

From that you can get a Quaternion out that is a direction and a rotation around that direction.

So if you you're looking to get the pitch, roll and yaw you can retrieve those from the Quaternion directly;

    public class MyAndroidStudioSandboxGame extends Game {

        @Override
        public void create () {
        }

        @Override
        public void render () {
            Gdx.gl.glClearColor(1, 0, 0, 1);
            Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);

            float[] mat = new float[4 * 4];
            Gdx.input.getRotationMatrix(mat);

            Matrix4 m = new Matrix4(mat);

            Quaternion q = m.getRotation(new Quaternion());

            Gdx.app.log("SANDBOX", String.format(
                "Pitch=%.2f, Roll=%.2f, Yaw=%.2f", 
                q.getPitch(), q.getRoll(), q.getYaw()));
        }
    }

The above app will log the orientation (Euler angles) of the device to logcat. There are also getPitchRad, getRollRad and getYawRad that gives you the values in radians.

\$\endgroup\$
  • \$\begingroup\$ How can I use the returned values to get the rotation of the device in the three axes? \$\endgroup\$ – Alex Pi Aug 30 '16 at 21:37
  • \$\begingroup\$ @AlexPi I added a code sample to show how to get the angles out. Hope this helps. \$\endgroup\$ – bornander Aug 31 '16 at 5:57

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.