Question

我有一个标题......

Components.h

namespace ComponentManager
{
  void InitializeComponents(std::size_t numComponents);
  void AddComponent(const Component& c, std::size_t position);
  std::vector<Component> GetComponents();
}

......和实施：

Components.cpp

#include "Components.h"

std::vector<ComponentManager::Component> components;

void ComponentManager::InitializeComponents(std::size_t numComponents)
{
  components.resize(numComponents, Component());
}

void ComponentManager::AddComponent(const Component& c, std::size_t pos)
{
  components[pos] = c;
}

std::vector<ComponentManager::Component> ComponentManager::GetComponents()
{
  return components;
}

在 main.cpp 中，我确保初始化组件向量，并添加几个组件。在调试每个AddComponent（...）调用时，我看到组件实际存储在向量中。但是，当我调用GetComponents（）时，返回的向量是不同的，就好像组件从未存储过一样。

我错过了什么？

编辑：添加main.cpp（在main（）函数内）

//Inside EntityManager::Initialize(), I call ComponentManager::InitializeComponents()
EntityManager::Initialize(5000);
for (unsigned int i = 0; i < 10; ++i)
{
    uint16_t handle = EntityManager::CreatePlayer(static_cast<float>(i), 50.0f * i);
    //Inside EntityManager::AddComponent, I call ComponentManager::AddComponent(..)
    EntityManager::AddComponent(handle, ComponentManager::POSITION_COMPONENT | ComponentManager::RENDERABLE_COMPONENT);
}
auto components = ComponentManager::GetComponents(); //this vector does not contain the elements that were added.

Answer 1

最初，这是组件的定义：

union Component
{
    PositionComponent positionComponent;
    VelocityComponent velocityComponent;
    AccelerationComponent accelerationComponent;
    RenderableComponent renderableComponent;
    Component() {}
    ~Component() {}
    Component(const Component& other) {}
    Component& operator=(const Component& other)
    {
        std::memmove(this, &other, sizeof(other));
        return *this;
    }
};

添加构造函数和复制构造函数的定义是修复：

union Component
{
    PositionComponent positionComponent;
    VelocityComponent velocityComponent;
    AccelerationComponent accelerationComponent;
    RenderableComponent renderableComponent;
    Component() 
    {  
        std::memset(this, 0, sizeof(Component)); 
    }
    ~Component() {}
    Component(const Component& other)
    {
        std::memmove(this, &other, sizeof(other));
    }
    Component& operator=(const Component& other)
    {
        std::memmove(this, &other, sizeof(other));
        return *this;
    }
};

Global std :: vector不保留数据

1 个答案: