Il 26/07/2010 18:58, BlueAngel ha scritto:

Hi lists,
I'm working with the Serialization library but I'm having some troubles with it.
The tutorials in the website shown me much but still I need help.

I'm using XML archives.
I have this classes actually (these classes are all builders/prototypes, they serialize the datas and then they should make a new object with those datas):
Serializer (an interface, every class which need serialization must be derived from this, however this is only a marker, it will be not serialized)
RenderableSerializer : public Serializer - this isn't pure virtual however shouldn't be never serialized directly (since the object made by this class is a pure virtual one) - These will use the tag <renderable>
SkyboxSerializer : public RenderableSerializer - these will use the tag <skybox>
EntitySerializer : public Serializer - these will use the tag <entity>
many other classes will be added in future and they'll all derive form RenderableSerializer.

Now the problem is EntitySerializer have a pointer to a RenderableSerializer and when I serialize EntitySerializer the pointer to that class is considered to be a RenderableSerializer and not the derived class. I don't know at priori which class is the base class and this lead to problem.
If I serialize a SkyboxSerializer I have the correct tag: a <skybox> which have inside a <renderable> and the datas are correct.
If I try to serialize an Entity I had a lot of problem, mostly just make the library crash. As I've seen in the tutorial I should register all the derived classes before pass the pointer to the Archive. I did it registering the SkyboxSerializer classes but it lead to a wrong xml: a correct <entity> tag which have a correct <skybox> with all it's data but also a wrong <renderable> tag which have inside the same data of the tag <skybox> instead of the data of a RenderableSerializer class.

Now the question is: is there a correct way to use the library this way? With a pointer to a base class of which the derived is not known?
My code is too big and I made many attempt to use the library so I'm not posting it in this message. If you need it I will post it.
Thank you for your replies.
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It seems no one know the answer. I hope it's just I made a too vague request. Here's the partial code (load function are implemented the same way, simmetrically):
EntitySerializer.hpp:
void save(xml_oarchive& ar, const unsigned int version) const
{
    ar << make_nvp("EntityName", _nome); // string
    ar.register_type(static_cast<SkyBoxSerializer *>(NULL)); // Note: this is just for debug, in the future I'll make a function in every class derived from Serializer which register itself when needed.
    ar << make_nvp(_renderable->getTagName().c_str(), _renderable);
}

SkyboxSerializer.hpp:
void save(xml_oarchive& ar, const unsigned int version) const
{
    ar << make_nvp("renderable",
      boost::serialization::base_object< RenderableSerializer >(*this));
    //RenderableSerializer::save(ar, version); // If I use this line instead of the previous it de/serializer correctly but I know this is a dirty work-around and I want to avoid it.
    ar << make_nvp("shader_file", _fx_file); // std::string
    ar << make_nvp("mesh_file", _mesh_filename); // std::string
    ar << make_nvp("cubemap_file", _tex_filename); // std::string
}
RenderableSerialier.hpp:
void save(xml_oarchive& ar, const unsigned int version) const
{
    ar << make_nvp("scala", _scala); // struct vector
    ar << make_nvp("rotazione", _rotazione); // struct vector
    ar << make_nvp("posizione", _posizione); // struct vector
}
VectorSerializer.hpp:
struct vettore
{
    float x, y, z;
};

namespace boost
{
    namespace serialization
    {
        template<class Archive> void serialize(Archive& ar, vettore& vec, const unsigned int version)
        {
            ar & make_nvp("x", vec.x);
            ar & make_nvp("y", vec.y);
            ar & make_nvp("z", vec.z);
        }
    }
}

Serializer.hpp:
virtual void save(xml_oarchive& ar, const unsigned int version) const = 0;

And this is the xml resultant:
<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<!DOCTYPE boost_serialization>
<boost_serialization signature="serialization::archive" version="7">
<entity class_id="0" tracking_level="0" version="0">
    <EntityName>skybohx</EntityName>
    <skybox class_id="1" tracking_level="1" version="0" object_id="_0">
        <renderable class_id="2" tracking_level="1" version="0" object_id="_1">
            <renderable object_id_reference="_1"></renderable>
            <shader_file>skybox.fx</shader_file>
            <mesh_file>asd.x</mesh_file>
            <cubemap_file>CubeMap.dds</cubemap_file>
        </renderable>
        <shader_file>skybox.fx</shader_file>
        <mesh_file>asd.x</mesh_file>
        <cubemap_file>CubeMap.dds</cubemap_file>
    </skybox>
</entity>
</boost_serialization>

As you can see the renderable tag inside the skybox tag is wrong. The <renderable> should have:
<scala>
    <x>3</x>
    <y>3</y>
    <z>3</z>
</scala>
<rotazione>
    <x>2</x>
    <y>2</y>
    <z>2</z>
</rotazione>
<posizione>
    <x>1</x>
    <y>1</y>
    <z>1</z>
</posizione>

Why that tag serialize the derived class instead of itself?
Thank you again for your answers.