source/game/owned.h

   1 #ifndef MSP_GAME_OWNED_H_
   2 #define MSP_GAME_OWNED_H_
   3
   4 #include <stdexcept>
   5 #include "events.h"
   6 #include "handle.h"
   7 #include "stage.h"
   8
   9 namespace Msp::Game {
  10
  11 class Component;
  12 class Entity;
  13
  14 template<typename T>
  15 class Owned: public Handle<T>
  16 {
  17 public:
  18         Owned() = default;
  19
  20         template<typename P, typename... Args>
  21         Owned(Handle<P>, Args &&...);
  22
  23         template<typename P, typename... Args>
  24         Owned(P &parent, Args &&... args): Owned(Handle<P>::from_object(&parent), std::forward<Args>(args)...) { }
  25
  26         Owned(Owned &&other): Handle<T>(other) { other.ptr = nullptr; }
  27         Owned &operator=(Owned &&other);
  28         ~Owned() { destroy(); }
  29
  30 private:
  31         template<typename O>
  32         static Stage &get_stage(O &);
  33
  34         void destroy();
  35 };
  36
  37
  38 template<typename T>
  39 template<typename P, typename... Args>
  40 Owned<T>::Owned(Handle<P> parent, Args &&... args)
  41 {
  42         if(!parent)
  43                 throw std::invalid_argument("Owned::Owned");
  44
  45         Stage &stage = get_stage(*parent);
  46         Pool<T> &pool = stage.get_pools().template get_pool<T>();
  47         this->ptr = pool.create(parent, std::forward<Args>(args)...);
  48         if constexpr(std::is_base_of_v<Component, T>)
  49         {
  50                 parent->add_component(*this);
  51                 stage.get_event_source().emit<Events::ComponentCreated>(*this);
  52         }
  53         else
  54         {
  55                 parent->add_child(*this);
  56                 stage.get_event_source().emit<Events::EntityCreated>(*this);
  57         }
  58 }
  59
  60 template<typename T>
  61 Owned<T> &Owned<T>::operator=(Owned &&other)
  62 {
  63         destroy();
  64
  65         this->ptr = other.ptr;
  66         other.ptr = nullptr;
  67
  68         return *this;
  69 }
  70
  71 template<typename T>
  72 template<typename O>
  73 Stage &Owned<T>::get_stage(O &obj)
  74 {
  75         if constexpr(std::is_base_of_v<Component, O>)
  76                 return get_stage(*obj.get_entity());
  77         else
  78                 return obj.get_stage();
  79 }
  80
  81 template<typename T>
  82 void Owned<T>::destroy()
  83 {
  84         T *obj = this->get();
  85         if(!obj)
  86                 return;
  87
  88         Stage &stage = get_stage(*obj);
  89
  90         if constexpr(std::is_base_of_v<Component, T>)
  91         {
  92                 stage.get_event_source().emit<Events::ComponentDestroyed>(*this);
  93                 obj->get_entity()->remove_component(*this);
  94         }
  95         else if(auto parent = obj->get_parent().get())
  96         {
  97                 stage.get_event_source().emit<Events::EntityDestroyed>(*this);
  98                 parent->remove_child(*this);
  99         }
 100
 101         Pool<T> &pool = stage.get_pools().template get_pool<T>();
 102         pool.destroy(this->ptr);
 103 }
 104
 105 } // namespace Msp::Game
 106
 107 #endif