我正在尝试将我的游戏引擎用于外部项目。一切正常但我在尝试创建自定义组件时遇到问题（继承自ABhaviour，它是一个抽象类，表示可以激活/禁用的组件）。
GameObject.h （使用__declspec（dllexport）导出）
// [...]
template <typename Class, typename ... Args>
std::shared_ptr<Class> GameObject::AddComponent(Args... args)
{
auto newComp = std::make_shared<Class>(std::forward<Args>(args)...);
m_components[typeid(*newComp).hash_code()] = newComp;
m_components[typeid(*newComp).hash_code()]->SetOwner(*this);
return newComp;
}
// [...]
在另一个项目中（使用我的游戏引擎），我正在尝试创建自定义ABehaviour：
PlayerController.h
#pragma once
#include <ElkGameEngine/Objects/Components/Behaviours/ABehaviour.h>
class PlayerController :ElkGameEngine::Objects::Components::Behaviours::ABehaviour
{
PlayerController() = default;
~PlayerController() = default;
void Update();
};
之后我将自定义组件添加到我的“Player”GameObject：
Main.cpp的
#include <ElkGameEngine/ElkGameEngine.h>
#include <ElkGameEngine/Objects/AObject.h>
#include <ElkGameEngine/Objects/Components/AComponent.h>
#include "PlayerController.h"
using namespace ElkGameEngine::Objects::Components;
using namespace ElkGameEngine::Objects::Components::Behaviours;
int main()
{
ElkGameEngine::Managers::EngineManager elkGameEngine;
elkGameEngine.GetSceneManager()->CreateScene("ElkCraft");
auto& player = elkGameEngine.GetSceneManager()->CreateEmptyGameObject("Player");
player.AddComponent<PlayerController>(); /* Here is the problem */
while (elkGameEngine.IsRunning())
{
elkGameEngine.PreUpdate();
elkGameEngine.PostUpdate();
}
return EXIT_SUCCESS;
}
Visual Studio很不高兴并打印出来：
Severity Code Description Project File Line Suppression State
Error C2440 '<function-style-cast>': cannot convert from 'const std::shared_ptr<PlayerController>' to 'std::shared_ptr<ElkGameEngine::Objects::Components::AComponent>' ElkCraft c:\program files (x86)\microsoft visual studio\2017\community\vc\tools\msvc\14.12.25827\include\memory 1472
Error C2228 left of '.swap' must have class/struct/union ElkCraft c:\program files (x86)\microsoft visual studio\2017\community\vc\tools\msvc\14.12.25827\include\memory 1472
输出窗口：
1>------ Build started: Project: ElkCraft, Configuration: Debug x64 ------
1>Could Not Find C:\Users\adrie\Desktop\GROUP_2\PFA\ElkCraft\*.dll
1>main.cpp
1>c:\program files (x86)\microsoft visual studio\2017\community\vc\tools\msvc\14.12.25827\include\memory(1472): error C2440: '<function-style-cast>': cannot convert from 'const std::shared_ptr<PlayerController>' to 'std::shared_ptr<ElkGameEngine::Objects::Components::AComponent>'
1>c:\program files (x86)\microsoft visual studio\2017\community\vc\tools\msvc\14.12.25827\include\memory(1472): note: No constructor could take the source type, or constructor overload resolution was ambiguous
1>c:\users\adrie\desktop\group_2\pfa\elkengine\build\elkgameengine\include\elkgameengine\objects\gameobject.h(53): note: see reference to function template instantiation 'std::shared_ptr<ElkGameEngine::Objects::Components::AComponent> &std::shared_ptr<ElkGameEngine::Objects::Components::AComponent>::operator =<PlayerController>(const std::shared_ptr<PlayerController> &) noexcept' being compiled
1>c:\users\adrie\desktop\group_2\pfa\elkengine\build\elkgameengine\include\elkgameengine\objects\gameobject.h(55): note: see reference to function template instantiation 'std::shared_ptr<ElkGameEngine::Objects::Components::AComponent> &std::shared_ptr<ElkGameEngine::Objects::Components::AComponent>::operator =<PlayerController>(const std::shared_ptr<PlayerController> &) noexcept' being compiled
1>c:\users\adrie\desktop\group_2\pfa\elkcraft\sources\main.cpp(18): note: see reference to function template instantiation 'std::shared_ptr<PlayerController> ElkGameEngine::Objects::GameObject::AddComponent<PlayerController,>(void)' being compiled
1>c:\program files (x86)\microsoft visual studio\2017\community\vc\tools\msvc\14.12.25827\include\memory(1472): error C2228: left of '.swap' must have class/struct/union
1>Generating Code...
1>Compiling...
1>PlayerController.cpp
1>Generating Code...
1>Done building project "ElkCraft.vcxproj" -- FAILED.
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
我认为问题来自于我的游戏引擎（它是一组DLL）正在导出模板化方法（AddComponent和其他类似GetComponent）。