X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=source%2Fbindable.h;h=f534d7afd8e9788e412dd0d2ddd876eee0091c8e;hb=f33a98b1a044c8ac7b12778cbca6c4a124875e4a;hp=cd012fbbcef3d50b984a6dafbace86f49ce7f433;hpb=f17794d55923d4fb4f63e9d082d8d84a735a04e8;p=libs%2Fgl.git

diff --git a/source/bindable.h b/source/bindable.h
index cd012fbb..f534d7af 100644
--- a/source/bindable.h
+++ b/source/bindable.h
@@ -1,16 +1,13 @@
-/* $Id$
-
-This file is part of libmspgl
-Copyright © 2010  Mikko Rasa, Mikkosoft Productions
-Distributed under the LGPL
-*/
-
 #ifndef MSP_GL_BINDABLE_H_
 #define MSP_GL_BINDABLE_H_
 
 namespace Msp {
 namespace GL {
 
+/**
+A helper class for single-point binding.  Provides tracking of the currently
+bound object.
+*/
 template<typename T>
 class Bindable
 {
@@ -24,18 +21,48 @@ protected:
 		if(obj==cur_obj)
 			return false;
 
-		cur_obj=obj;
+		cur_obj = obj;
 		return true;
 	}
 
 public:
-	const T *current() const { return cur_obj; }
+	static const T *current() { return cur_obj; }
 };
 
 template<typename T>
 const T *Bindable<T>::cur_obj;
 
 
+/**
+A helper class for Bindables that revert to a default object on unbind.
+*/
+template<typename T>
+class BindableWithDefault: protected Bindable<T>
+{
+protected:
+	BindableWithDefault() { }
+
+public:
+	static const T *current()
+	{
+		if(!Bindable<T>::cur_obj)
+			Bindable<T>::cur_obj = &default_object();
+		return Bindable<T>::cur_obj;
+	}
+
+	static void unbind()
+	{
+		default_object().bind();
+	}
+
+	static const T &default_object()
+	{
+		static T obj;
+		return obj;
+	}
+};
+
+
 /**
 RAII class for binding things.  Binds the thing upon construction and unbinds
 it upon destruction.  If a null pointer is given, unbinds upon construction and
@@ -44,35 +71,88 @@ does nothing upon destruction.
 class Bind
 {
 private:
-	struct Base
-	{
-		virtual ~Base() { }
-	};
+	typedef void CleanupFunc();
+
+	CleanupFunc *cleanup;
+
+public:
+	template<typename T>
+	Bind(T *o) { init(o); }
 
 	template<typename T>
-	struct Binder: Base
+	Bind(const T *o) { init(o); }
+
+	template<typename T>
+	Bind(const T &o) { init(&o); }
+
+private:
+	template<typename T>
+	void init(const T *o)
 	{
-		const T &obj;
+		cleanup = (o ? &unbind<T> : 0);
+		if(o)
+			o->bind();
+		else
+			T::unbind();
+	}
+
+public:
+	~Bind()
+	{ if(cleanup) cleanup(); }
 
-		Binder(const T &o): obj(o) { obj.bind(); }
-		~Binder() { obj.unbind(); }
-	};
+private:
+	template<typename T>
+	static void unbind()
+	{ T::unbind(); }
+};
 
-	Base *binder;
+
+/**
+Similar to Bind, but restores previous binding upon destruction.
+*/
+class BindRestore
+{
+private:
+	typedef void CleanupFunc(const void *);
+
+	const void *old;
+	CleanupFunc *cleanup;
 
 public:
 	template<typename T>
-	Bind(const T &o): binder(new Binder<T>(o)) { }
+	BindRestore(T *o) { init(o); }
 
 	template<typename T>
-	Bind(const T *o): binder(o ? new Binder<T>(*o) : 0) { if(!o) T::unbind(); }
+	BindRestore(const T *o) { init(o); }
+
+	template<typename T>
+	BindRestore(const T &o) { init(&o); }
 
 private:
-	Bind(const Bind &);
-	Bind &operator=(const Bind &);
+	template<typename T>
+	void init(T *o)
+	{
+		old = T::current();
+		cleanup = (o!=old ? &restore<T> : 0);
+		if(o)
+			o->bind();
+		else if(old)
+			T::unbind();
+	}
 
 public:
-	~Bind() { delete binder; }
+	~BindRestore()
+	{ if(cleanup) cleanup(old); }
+
+private:
+	template<typename T>
+	static void restore(const void *o)
+	{
+		if(o)
+			reinterpret_cast<const T *>(o)->bind();
+		else
+			T::unbind();
+	}
 };
 
 } // namespace GL