@Override
 public void reset() {
   mCenter.zero();
   mDelta.zero();
   mRim.zero();
   mVelocity.zero();
   mStrength = DEFAULT_STRENGTH;
   mAreaRadius = 0.0f;
   mMagnetRadius = 0.0f;
 }
  private void applyMagnetism(GameObject target, float centerX, float centerY, float timeDelta) {
    mCenter.set(centerX, centerY);
    final float targetX = target.getCenteredPositionX();
    final float targetY = target.getCenteredPositionY();
    mDelta.set(targetX, targetY);
    mDelta.subtract(mCenter);

    final float distanceFromCenter2 = mDelta.length2();
    final float area2 = mAreaRadius * mAreaRadius;
    if (distanceFromCenter2 < area2) {
      mRim.set(mDelta);
      mRim.normalize();
      mRim.multiply(mMagnetRadius);
      mRim.add(mCenter);
      // rim is now the closest point on the magnet circle

      // remove gravity
      final Vector2 targetVelocity = target.getVelocity();
      GravityComponent gravity = target.findByClass(GravityComponent.class);
      final Vector2 gravityVector = gravity.getGravity();
      mVelocity.set(gravityVector);
      mVelocity.multiply(timeDelta);
      targetVelocity.subtract(mVelocity);

      mDelta.add(targetVelocity);
      mDelta.normalize();
      mDelta.multiply(mMagnetRadius);
      mDelta.add(mCenter);

      // mDelta is now the next point on the magnet circle in the direction of
      // movement.

      mDelta.subtract(mRim);
      mDelta.normalize();
      // Now mDelta is the tangent to the magnet circle, pointing in the direction
      // of movement.

      mVelocity.set(mDelta);
      mVelocity.normalize();

      // mVelocity is now the direction to push the player

      mVelocity.multiply(mStrength);
      float weight = 1.0f;
      if (distanceFromCenter2 > mMagnetRadius * mMagnetRadius) {
        float distance = (float) Math.sqrt(distanceFromCenter2);
        weight = (distance - mMagnetRadius) / (mAreaRadius - mMagnetRadius);
        weight = 1.0f - weight;
        mVelocity.multiply(weight);
      }
      final float speed = targetVelocity.length();
      targetVelocity.add(mVelocity);
      if (targetVelocity.length2() > (speed * speed)) {
        targetVelocity.normalize();
        targetVelocity.multiply(speed);
      }
    }
  }