[Rock-dev] changes for base::type::PointCloud

[Alexander Duda]

I updated the base type PointClound. All channels are now stored as
uint8_t. I also added the functions "from" and "to" to convert the
channels into the right type. Unfortunately the only types which are
supported right now are fundamental types which have the same size
across compilers and architectures. To ensure that no one is using other
types I specialized the conversion template for allowed types and set
the generalized template to private.

I do not have more time to put into that right now. If anyone else wants
to contribute please tell me. 

Possible improvements which should be compatible with the proposed type
but would kind of doubling the existing serialization process:
* use boost to serialize structs (see ros PointCloud)
* use typelib?

Thoughts?

Alex

Example:
    PointCloud point_cloud;
    std::vector<float> values;
    values.push_back(10.2);
    values.push_back(100.2);
    point_cloud.channelFrom("channel_name",values);

    std::vector<uint32_t> values2;
    values2.push_back(1);
    values2.push_back(2);
    point_cloud.channelFrom("val2",values2);

    std::vector<float> values3;
    point_cloud.channelTo("channel_name",values3);
    

On Mon, 2011-10-10 at 16:06 +0200, Alexander Duda wrote:
> On Mon, 2011-10-10 at 14:44 +0200, Jakob Schwendner wrote:
> > Hi Alex,
> > 
> > On 10/10/2011 02:36 PM, Alexander Duda wrote:
> > > I looked into the base type point cloud and I missing the ability to
> > > save informations for each point. Because of that and a different naming
> > > conventions than we use, I would like to do the following changes:
> > >
> > > * rename pointcloud.h to point_cloud.h
> > > * rename base::samples::Pointcloud to base::samples::PointCloud
> > envire also uses Pointcloud instead of PointCloud. Should stay as it is 
> > for consistency.
> 
> I think it is more important to be consistent over all base types than
> to be consistent between envire::Pointcloud and
> base::samples::PointCloud.
> 
> Furthermore so far there is no relation between envire::Pointcloud and
> base::samples::PointCloud. I looked into the implementation of envire,
> the following types can be stored with each point:
> --> Eigen::Vector3d (vertex color, vertex normal)
> --> double (vertex variance)
> --> enum (vertex attribut)
> 
> For me this are attributes that does not relay belong to a point in a
> point cloud. Envire is using the point cloud to store vertex information
> which should probably better be stored in a more specialized class
> (PolyData for example).  
> 
> Nevertheless I agree it would be nice to to use a more generalized 
> way to save channel information. I do not really like the copy overhead
> for a function like getChannel<Type>(name ), but on the plus side, we
> could reduce the message size dramatically for information which does
> not need float. Therefore I think it is a good way to store the data,
> like you said, as uint8_t.
> 
> > > * move base::Point to base::samples::point_cloud::Point
> > > (otherwise Point should go into its own header)
> > ok.
> > > * add a new vector field for channel informations
> > >
> > > OLD VERSION:
> > > namespace base {
> > >      typedef base::Vector3d    Point;
> > >
> > >      namespace samples {
> > >          struct Pointcloud
> > >          {
> > >              Time time;
> > >
> > >              std::vector<base::Point>  points;
> > >          };
> > >      }
> > > }
> > >
> > > NEW VERSION:
> > > namespace base{ namespace samples {
> > >      namespace point_cloud {
> > >          struct Channel
> > >          {
> > >              std::string name;
> > >              std::vector<float>  values;
> > >          };
> > >          typedef base::Vector3d Point;
> > >      }
> > >
> > >      struct PointCloud
> > >      {
> > >          base::Time time;
> > >          std::vector<point_cloud::Point>  points;
> > >          std::vector<point_cloud::Channel>  channels;
> > >      };
> > > }}
> > >
> > > I talked to the guys which are using the type and it is fine for them
> > > therefore I am going to push the changes at the end of the day if no one
> > > is yelling ;-).
> > About the channel information, the problem is, that you most likely want 
> > very different types (or at least this was the case in envire). One way 
> > would be to use a uint8_t instead of the float and provide some 
> > functions to convert the data to your type, like e.g. getChannel<Type>( 
> > name ).
> > It's doubling the metadata mechanism in envire, but then I don't have a 
> > good solution right now, to combine envire and orogen types better, 
> > without rewriting a lot.
> > 
> > Jakob
> 
> -- 
> Dipl.-Ing. Alexander Duda 
> Unterwasserrobotik
> 
> DFKI Bremen
> Robotics Innovation Center
> Robert-Hooke-Straße 5
> 28359 Bremen, Germany
> 
> Phone: +49 (0)421 178-456620
> Fax:   +49 (0)421 178-454150
> E-Mail: alexander.duda at dfki.de
> 
> Weitere Informationen: http://www.dfki.de/robotik
> -----------------------------------------------------------------------
> Deutsches Forschungszentrum fuer Kuenstliche Intelligenz GmbH
> Firmensitz: Trippstadter Straße 122, D-67663 Kaiserslautern
> Geschaeftsfuehrung: Prof. Dr. Dr. h.c. mult. Wolfgang Wahlster
> (Vorsitzender) Dr. Walter Olthoff
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> 
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-- 
Dipl.-Ing. Alexander Duda 
Unterwasserrobotik

DFKI Bremen
Robotics Innovation Center
Robert-Hooke-Straße 5
28359 Bremen, Germany

Phone: +49 (0)421 178-456620
Fax:   +49 (0)421 178-454150
E-Mail: alexander.duda at dfki.de

Weitere Informationen: http://www.dfki.de/robotik
-----------------------------------------------------------------------
Deutsches Forschungszentrum fuer Kuenstliche Intelligenz GmbH
Firmensitz: Trippstadter Straße 122, D-67663 Kaiserslautern
Geschaeftsfuehrung: Prof. Dr. Dr. h.c. mult. Wolfgang Wahlster
(Vorsitzender) Dr. Walter Olthoff
Vorsitzender des Aufsichtsrats: Prof. Dr. h.c. Hans A. Aukes
Amtsgericht Kaiserslautern, HRB 2313
Sitz der Gesellschaft: Kaiserslautern (HRB 2313)
USt-Id.Nr.:    DE 148646973
Steuernummer:  19/673/0060/3