1 #ifndef MSP_GAME_SYSTEM_H_
2 #define MSP_GAME_SYSTEM_H_
5 #include <msp/time/timedelta.h>
6 #include "accessguard.h"
8 #include "reflection.h"
22 UPDATE = READ_OLD | WRITE,
23 CHAINED_UPDATE = READ_FRESH | WRITE
28 DependencyFlags flags = NO_DEPENDENCY;
29 const Reflection::ClassBase &type;
30 void (*prepare)(Stage &) = nullptr;
31 void (*commit)(Stage &) = nullptr;
32 void (*unblock)(DependencyFlags) = nullptr;
33 void (*block)(DependencyFlags) = nullptr;
35 Dependency(const Reflection::ClassBase &t): type(t) { }
38 class Activator: public NonCopyable
44 Activator(System &s): system(s) { system.begin_tick(); }
45 ~Activator() { system.end_tick(); }
50 std::vector<std::function<void()>> deferred_queue;
51 std::vector<Dependency> dependencies;
53 static thread_local System *active;
55 System(Stage &s): stage(s) { }
57 virtual ~System() = default;
59 Stage &get_stage() const { return stage; }
63 void declare_dependency(DependencyFlags);
67 virtual void tick(Time::TimeDelta) = 0;
69 virtual void deferred_tick();
73 void defer(F &&f) { deferred_queue.emplace_back(std::forward<F>(f)); }
78 inline void System::declare_dependency(DependencyFlags flags)
80 if(!std::is_base_of_v<Component, T>)
81 throw std::invalid_argument("System::declare_dependency");
83 const Reflection::ClassBase &type = stage.get_reflector().get_or_create_class<T>();
84 auto i = find_if(dependencies, [&type](const Dependency &d){ return &d.type==&type; });
86 if(i!=dependencies.end())
87 flags = static_cast<DependencyFlags>(flags|i->flags);
89 Dependency &dep = (i!=dependencies.end() ? *i : dependencies.emplace_back(type));
91 if constexpr(requires(T &c) { typename T::Data; c.prepare_tick(); c.commit_tick(); })
94 dep.unblock = +[](DependencyFlags f){
95 if(f&READ_OLD) AccessGuard::get_instance().unblock<AccessGuard::Read<typename T::Data>>();
96 if(f&WRITE) AccessGuard::get_instance().unblock<AccessGuard::Write<typename T::Data>>();
98 dep.block = +[](DependencyFlags f){
99 if(f&READ_OLD) AccessGuard::get_instance().block<AccessGuard::Read<typename T::Data>>();
100 if(f&WRITE) AccessGuard::get_instance().block<AccessGuard::Write<typename T::Data>>();
105 dep.prepare = +[](Stage &s){ s.iterate_objects<T>([](T &c){ c.prepare_tick(); }); };
106 dep.commit = +[](Stage &s){ s.iterate_objects<T>([](T &c){ c.commit_tick(); }); };
111 } // namespace Msp::Game