vecs::Observer< Components > Class Template Reference

Observer class for tracking component changes within a system. More...

#include <vecs.h>

Inheritance diagram for vecs::Observer< Components >:

Public Member Functions
	Observer ()
	Constructs an Observer for the specified components.
	Observer (const Observer &)=delete
Observer &	operator= (const Observer &)=delete
	Observer (Observer &&)=delete
Observer &	operator= (Observer &&)=delete
const std::vector< Entity > &	added () const override
	Retrieves the entities that have been added for the first time with the observed components.
const std::vector< Entity > &	inserted () const override
	Retrieves the entities that have been inserted with the observed components.
const std::vector< Entity > &	removed () const override
	Retrieves the entities that have been had the observed components removed.

Detailed Description

template<typename... Components>
class vecs::Observer< Components >

Observer class for tracking component changes within a system.

The Observer class enables systems to monitor specific components, tracking entities as they are added with the specified components.

Template Parameters

Components

The types of components to be observed.

Example usage:

world.add_system([](const Observer<int>& observer, Query<int>& query) {
   for (const auto& e : observer.inserted()) {
       auto i = query.get(e);
       if (i) {
           printf("Entity '%zu' had int with value inserted = %i\n", e, std::get<0>(*i));
       }
   }
});
 
world.spawn().insert(3);
world.spawn().insert(2);
world.spawn().insert(1);

Constructor & Destructor Documentation

Observer()

template<typename... Components>

vecs::Observer< Components >::Observer ( )

inline

Constructs an Observer for the specified components.

Initializes the observer to monitor entities with the specified components.

Member Function Documentation

added()

template<typename... Components>

const std::vector< Entity > & vecs::Observer< Components >::added ( ) const

inlineoverridevirtual

Retrieves the entities that have been added for the first time with the observed components.

Returns a reference to a vector of entities that were added with the specified components. If no entities were added, an empty vector is returned.

Returns

A reference to a vector of added entities.

Implements vecs::TypeErasedObserver.

inserted()

template<typename... Components>

const std::vector< Entity > & vecs::Observer< Components >::inserted ( ) const

inlineoverridevirtual

Retrieves the entities that have been inserted with the observed components.

Returns a reference to a vector of entities that were inserted with the specified components. If no entities were inserted, an empty vector is returned.

Returns

A reference to a vector of inserted entities.

Implements vecs::TypeErasedObserver.

removed()

template<typename... Components>

const std::vector< Entity > & vecs::Observer< Components >::removed ( ) const

inlineoverridevirtual

Retrieves the entities that have been had the observed components removed.

Returns a reference to a vector of entities that have had the specified components removed. If no components were inserted, an empty vector is returned.

Returns

A reference to a vector of entities with removed components.

Implements vecs::TypeErasedObserver.

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The documentation for this class was generated from the following file:

• vecs.h