OniGrabber wrongly assumes image data is RGB

[nh2]

In openni_device_oni.cpp:

boost::shared_ptr<openni_wrapper::Image> 
openni_wrapper::DeviceONI::getCurrentImage(boost::shared_ptr<xn::ImageMetaData> image_meta_data) const throw ()
{
  return (boost::shared_ptr<openni_wrapper::Image> (new openni_wrapper::ImageRGB24 (image_meta_data)));
}

This leads to weirdly corrupted images when .oni files that have a different encoding are played back in pcl_openni_viewer or when using the -oni switch in kinfu_app.

The openni_wrapper::DeviceONI::DeviceONI constructor should check the XnPixelFormat returned by image_generator_.GetPixelFormat() and pick the correct Image type, or at least throw an error if that's not RGB instead of wrongly interpreting the data.

[nh2]

Please check out my commit above - if it's ok I'll make another PR with it on top of master.

[jspricke]

Sounds good +1 for a PR.

[stale]

Marking this as stale due to 30 days of inactivity. It will be closed in 7 days if no further activity occurs.

[kunaltyagi]

@nh2, if you're around and could you send a PR?

Else, anyone is welcome to create the patch and send a PR.