X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=source%2Fgame%2Fsystem.h;h=3d62c06276553821694651c0c5f15020845cc083;hb=a99b57a74252fd3de649d544d070b747f91fcf4d;hp=3b379178c1b6e27972cd60f9bfa31441bafbebe2;hpb=e3b8bcdcb5abfdc4cfaf0af0f9633ac15d1f3b69;p=libs%2Fgame.git

diff --git a/source/game/system.h b/source/game/system.h
index 3b37917..3d62c06 100644
--- a/source/game/system.h
+++ b/source/game/system.h
@@ -3,16 +3,51 @@
 
 #include <functional>
 #include <msp/time/timedelta.h>
+#include "component.h"
+#include "reflection.h"
+#include "stage.h"
 
 namespace Msp::Game {
 
-class Stage;
-
 class System
 {
+public:
+	enum DependencyFlags
+	{
+		NO_DEPENDENCY = 0,
+		READ_OLD = 1,
+		READ_FRESH = 3,
+		WRITE = 4,
+		UPDATE = READ_OLD | WRITE,
+		CHAINED_UPDATE = READ_FRESH | WRITE
+	};
+
+	struct Dependency
+	{
+		DependencyFlags flags = NO_DEPENDENCY;
+		const Reflection::ClassBase &type;
+		void (*prepare)(Stage &) = nullptr;
+		void (*commit)(Stage &) = nullptr;
+
+		Dependency(const Reflection::ClassBase &t): type(t) { }
+	};
+
+	class Activator: public NonCopyable
+	{
+	private:
+		System &system;
+
+	public:
+		Activator(System &s): system(s) { system.begin_tick(); }
+		~Activator() { system.end_tick(); }
+	};
+
 protected:
 	Stage &stage;
 	std::vector<std::function<void()>> deferred_queue;
+	std::vector<Dependency> dependencies;
+
+	static thread_local System *active;
 
 	System(Stage &s): stage(s) { }
 public:
@@ -20,7 +55,14 @@ public:
 
 	Stage &get_stage() const { return stage; }
 
+protected:
+	template<typename T>
+	void declare_dependency(DependencyFlags);
+
+public:
+	void begin_tick();
 	virtual void tick(Time::TimeDelta) = 0;
+	void end_tick();
 	virtual void deferred_tick();
 
 protected:
@@ -28,6 +70,29 @@ protected:
 	void defer(F &&f) { deferred_queue.emplace_back(std::forward<F>(f)); }
 };
 
+
+template<typename T>
+inline void System::declare_dependency(DependencyFlags flags)
+{
+	if(!std::is_base_of_v<Component, T>)
+		throw std::invalid_argument("System::declare_dependency");
+
+	const Reflection::ClassBase &type = stage.get_reflector().get_or_create_class<T>();
+	auto i = find_if(dependencies, [&type](const Dependency &d){ return &d.type==&type; });
+
+	if(i!=dependencies.end())
+		flags = static_cast<DependencyFlags>(flags|i->flags);
+
+	Dependency &dep = (i!=dependencies.end() ? *i : dependencies.emplace_back(type));
+	dep.flags = flags;
+	if constexpr(requires(T &c) { typename T::Data; c.prepare_tick(); c.commit_tick(); })
+		if(flags&WRITE)
+		{
+			dep.prepare = +[](Stage &s){ s.iterate_objects<T>([](T &c){ c.prepare_tick(); }); };
+			dep.commit = +[](Stage &s){ s.iterate_objects<T>([](T &c){ c.commit_tick(); }); };
+		}
+}
+
 } // namespace Msp::Game
 
 #endif