X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=source%2Fgame%2Fcomponent.h;h=44927ffd2e73c640f9d8a609f4e4b66984633572;hb=a99b57a74252fd3de649d544d070b747f91fcf4d;hp=6914c15282383a004b09117875e191dd56f6a6cd;hpb=248d62f7240d342982ade65a510be912b867fe49;p=libs%2Fgame.git

diff --git a/source/game/component.h b/source/game/component.h
index 6914c15..44927ff 100644
--- a/source/game/component.h
+++ b/source/game/component.h
@@ -18,12 +18,41 @@ public:
 	virtual ~Component() = default;
 
 	Handle<Entity> get_entity() const { return entity; }
+};
+
+template<typename T>
+class BufferedComponent: public Component
+{
+public:
+	using Data = T;
+	
+protected:
+	T data[2];
+	uint8_t read_index = 0;
+	uint8_t write_index = 0;
+	bool written = false;
 
-	virtual void pre_tick() { }
-	virtual void tick(Time::TimeDelta) { }
-	virtual void post_tick() { }
+	BufferedComponent(Handle<Entity> e): Component(e) { }
+
+	const T &read() const { return data[read_index]; }
+	T &write();
+
+public:
+	virtual void prepare_tick() { write_index = 1-read_index; written = false; }
+	virtual void commit_tick() { if(written) read_index = write_index; }
 };
 
+template<typename T>
+T &BufferedComponent<T>::write()
+{
+	if(!written && write_index!=read_index)
+	{
+		data[write_index] = data[read_index];
+		written = true;
+	}
+	return data[write_index];
+}
+
 } // namespace Msp::Game
 
 #endif