X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=source%2Fgame%2Fcomponent.h;h=e97b511a6ed658edbc9c221b2ca14a7ffa2927f7;hb=12c863fc1bc5456a4b3aceacc88904d76bd1d8bb;hp=6b49dd19e8c6e3f64da05ceb550616d1e2c31624;hpb=86057ab12bea9aaf40be2f1f2a0a3e64e94f0313;p=libs%2Fgame.git

diff --git a/source/game/component.h b/source/game/component.h
index 6b49dd1..e97b511 100644
--- a/source/game/component.h
+++ b/source/game/component.h
@@ -2,13 +2,15 @@
 #define MSP_GAME_COMPONENT_H_
 
 #include <msp/time/timedelta.h>
+#include "accessguard.h"
 #include "handle.h"
+#include "mspgame_api.h"
 
 namespace Msp::Game {
 
 class Entity;
 
-class Component
+class MSPGAME_API Component
 {
 protected:
 	Handle<Entity> entity;
@@ -20,6 +22,51 @@ public:
 	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;
+
+	BufferedComponent(Handle<Entity> e): Component(e) { }
+
+	const T &read() const;
+	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>
+const T &BufferedComponent<T>::read() const
+{
+#ifdef DEBUG
+	AccessGuard::get_instance().check<AccessGuard::Read<T>>();
+#endif
+	return data[read_index];
+}
+
+template<typename T>
+T &BufferedComponent<T>::write()
+{
+#ifdef DEBUG
+	AccessGuard::get_instance().check<AccessGuard::Write<T>>();
+#endif
+	if(!written && write_index!=read_index)
+	{
+		data[write_index] = data[read_index];
+		written = true;
+	}
+	return data[write_index];
+}
+
 } // namespace Msp::Game
 
 #endif