OGRE-Next  2.3
Object-Oriented Graphics Rendering Engine
OgreProperty.h File Reference

OGRE's property system allows you to associate values of arbitrary type with names, and have those values exposed via a self-describing interface. More...

#include "OgrePropertyPrerequisites.h"
#include "OgreAny.h"
#include "OgreIteratorWrappers.h"
#include "OgreException.h"
#include "OgreQuaternion.h"
#include "OgreMatrix4.h"
#include <boost/bind.hpp>
#include <boost/function.hpp>


class  Ogre::Property< T >
 Property instance with passthrough calls to a given object. More...
class  Ogre::PropertyBase
 Base interface for an instance of a property. More...
class  Ogre::PropertyDef
 Definition of a property of an object. More...
class  Ogre::PropertySet
 Defines a complete set of properties for a single object instance. More...
struct  Ogre::PropertyValue
 A simple structure designed just as a holder of property values between the instances of objects they might target. More...




typedef map< String, PropertyDef >::type Ogre::PropertyDefMap
 Map from property name to shared definition. More...
typedef map< String, PropertyValue >::type Ogre::PropertyValueMap
 Defines a transferable map of properties using wrapped value types (Ogre::Any) More...


enum  Ogre::PropertyType {
  Ogre::PROP_SHORT = 0 , Ogre::PROP_UNSIGNED_SHORT = 1 , Ogre::PROP_INT = 2 , Ogre::PROP_UNSIGNED_INT = 3 ,
  Ogre::PROP_LONG = 4 , Ogre::PROP_UNSIGNED_LONG = 5 , Ogre::PROP_REAL = 6 , Ogre::PROP_STRING = 7 ,
  Ogre::PROP_VECTOR2 = 8 , Ogre::PROP_VECTOR3 = 9 , Ogre::PROP_VECTOR4 = 10 , Ogre::PROP_COLOUR = 11 ,
  Ogre::PROP_BOOL = 12 , Ogre::PROP_QUATERNION = 13 , Ogre::PROP_MATRIX3 = 14 , Ogre::PROP_MATRIX4 = 15 ,
  Ogre::PROP_UNKNOWN = 999
 The type of a property. More...

Detailed Description

OGRE's property system allows you to associate values of arbitrary type with names, and have those values exposed via a self-describing interface.

Unlike Ogre::StringInterface, the values are passed as their native types without needing conversion to or from strings; they are simply wrapped in an Ogre::Any and casts are performed to access them.

Property values are actually not stored in this system; instead the property definitions reference getter & setter methods which provide the 'backing' for the property. This means you can directly expose features of your classes as properties without any duplication.
There are two aspects to exposing a property on your class. One is exposing the definition of the property (PropertyDef), which should be shared between all instances and probably stored in a static PropertyDefMap somewhere. The second is the instance 'wiring' which ensures that a call to set a property calls a method on this particular instance of the class; this is formed by a number of Property instances, contained in a PropertySet. Each Property has an explicit binding to getter and setter instance methods.
So, here's an example of setting up properties on an instance:
// Make sure the property definition is created
// propertyDefs is a variable of type PropertyDefMap, shared between instances
PropertyDefMap::iterator defi = propertyDefs.find("name");
if (defi == propertyDefs.end())
defi = propertyDefs.insert(PropertyDefMap::value_type("name",
"The name of the object.", PROP_STRING))).first;
// This has established the property definition, and its description.
// Now, we need to 'wire' a property instance for this object instance
// We assume the class is called 'Foo' and the instance is pointed to by a variable called 'inst'
// 'props' is a PropertySet, specific to the instance
OGRE_NEW Property<String>(&(defi->second),
boost::bind(&Foo::getName, inst),
boost::bind(&Foo::setName, inst, _1)));
#define OGRE_NEW
Definition: OgreMemoryAllocatorConfig.h:500
Definition: OgreProperty.h:113