我真的不知道如何解释这一点。
我在命名空间中有 2 个类 World 和 Entity：
阿尔忒弥斯::系统；
和一个类组件
artemis::组件；
我已经遇到了 World 和 Entity 的问题，在尝试编译时它说它们中的任何一个都不是声明的类型。（它们都相互包含）所以在两个类中，在命名空间中，我添加了一个前向声明。这似乎可以解决问题。
现在，当我尝试在 Component.h 中包含“世界”时，它给了我以下错误：
组件不是命名空间名称
我的 Component 类位于命名空间 artemis::component 中。
这真让我抓狂。我真的不明白是什么导致了这个错误。
头组件.h
#ifndef _COMPONENT_H_
#define _COMPONENT_H_
#include <bitset>
#include "BitSize.h"
#include "World.h"
#include <unordered_map>
#include <typeinfo>
#include <string>
#include <iostream>
#include <assert.h>
//#include "EntityManager.h"
using namespace std;
using namespace artemis::system;
namespace artemis {
namespace component {
class Component {
public:
virtual ~Component() = 0;
protected:
Component(){};
};
/**
* Identifies a bitset and id for a component object
* Do not instantiate a ComponentType, instead use the ComponentTypeManager.
* */
class ComponentType {
public:
ComponentType();
bitset<BITSIZE> getBit() const;
int getId() const;
private:
static bitset<BITSIZE> nextBit;
static int nextId;
bitset<BITSIZE> bit;
int id;
void init();
};
//Surpress unused variable warnning. Might need to rewrite it
//#pragma GCC diagnostic push
//#pragma GCC diagnostic ignored "-Wunused-variable"
/**
* Manages the id and bitset for every component based on their type.
* */
class ComponentTypeManager {
private:
ComponentTypeManager();
static unordered_map<size_t,ComponentType*> componentTypes;
public:
/**
*
**/
static ComponentType & getTypeFor(const type_info &t);
/**
* Gets the component type object
**/
template<typename c>
static ComponentType & getTypeFor() {
//Check if we are being legal with components and shizzle
//Component * c = (component*)0;
assert((std::is_base_of< Component, c >::value == true));
return getTypeFor(typeid(c));
}
/**
* Gets the bit set of a component
**/
template<typename c>
static bitset<BITSIZE> getBit() {
//Check if we are being legal with components and shizzle
//Component * c = (component*)0;
assert((std::is_base_of< Component, c >::value == true));
ComponentType & type = getTypeFor(typeid(c));
return type.getBit();
}
/**
* Gets the component id
**/
template<typename c>
static int getId() {
//Check if we are being legal with components and shizzle
assert((std::is_base_of< Component, c >::value == true));
ComponentType & type = getTypeFor(typeid(c));
return type.getId();
};
//typedef getCompBit bitset<BITSIZE>(*getBit<Component>)();
};
//#pragma GCC diagnostic pop
/*template<typename T>
class ComponentMapper {
private:
//ComponentType * type;
EntityManager * em;
public:
ComponentMapper(World &world) {
em = world.getEntityManager();
//type = ComponentTypeManager::getTypeFor<T>();
}
~ComponentType() {
type = nullptr;
em = nullptr;
}
T & get(Entity * e) {
return &(T)em->getComponent<T>(e);
}
};*/
};
};
#endif
标头实体.h
#ifndef _ENTITY_H
#define _ENTITY_H
#include <bitset>
#include <string>
#include <cstddef>
#include <typeinfo>
#include "BitSize.h"
#include "Component.h"
#include "ImmutableBag.h"
#include "World.h"
//#include "EntityManager.h"
using namespace artemis::util;
using namespace artemis::component;
//using namespace artemis;
using namespace std;
namespace artemis {
namespace system {
class World;
class Entity {
private:
int id;
long int uniqueId;
bitset<BITSIZE> typeBits;
bitset<BITSIZE> systemBits;
World * world;
//EntityManager * entityManager;
protected:
public:
Entity(World * world, int id);
~Entity();
int getID();
void setUniqueId(long int uniqueId);
long int getUniqueID();
bitset<BITSIZE> getTypeBits();
void addTypeBit(bitset<BITSIZE> bit);
void removeTypeBit(bitset<BITSIZE> bit);
bitset<BITSIZE> getSystemBits();
void addSystemBit(bitset<BITSIZE> bit);
void removeSystemBit(bitset<BITSIZE> bit);
void setSystemBits(bitset<BITSIZE> systemBits);
void setTypeBits(bitset<BITSIZE> typeBits);
void reset();
string toString();
void addComponent(Component * c);
//Might change to non template
template<typename c>
void removeComponent() {
//entityManager->removeComponent(this,ComponentTypeManager::getTypeFor<c>());
}
void removeComponent(ComponentType & type);
bool isActive();
Component * getComponent(ComponentType & type);
/*template<typename c>
Component * getComponent() {
return (c)entityManager->getComponent(ComponentTypeManager.getTypeFor<c>());
}*/
ImmutableBag<Component*> * getComponents();
void refresh();
void remove();
void setGroup(string group);
void setTag(string tag);
};
};
};
#endif // $(Guard token)
标头世界.h
#ifndef _WORLD_H_
#define _WORLD_H_
//#include "SystemManager.h"
//#include "EntityManager.h"
#include "ImmutableBag.h"
#include "Entity.h"
using namespace artemis::util;
namespace artemis {
namespace system {
class Entity;
class World {
public:
World();
~World();
//SystemManager * getSystemManager();
//EntityManager * getEntityManager();
//TagManager * getTagManager();
//GroupManager * getGroupManager();
int getDelta();
void setDetla(int delta);
void deleteEntity(Entity *e);
void refreshEntity(Entity *e);
//Entity* createEntity();
//Entity* getEntity(int entityID);
void loopStart();
private:
//SystemManager * systemManager;
//EntityManager * entityManager;
//TagManager * tagManager;
//GroupManager * grouManager;
int delta;
Bag<Entity*> refreshed;
Bag<Entity*> deleted;
};
};
};
#endif // $(Guard token)