X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=source%2Fbindable.h;h=bde5e85a11752b3a95a07de5187ad174b3c4a50a;hb=055f553b1a75f44e72f3c2b5a1c98c1e1e8f3f30;hp=cd012fbbcef3d50b984a6dafbace86f49ce7f433;hpb=f17794d55923d4fb4f63e9d082d8d84a735a04e8;p=libs%2Fgl.git

diff --git a/source/bindable.h b/source/bindable.h
index cd012fbb..bde5e85a 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
 {
@@ -24,22 +21,52 @@ 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
-does nothing upon destruction.
+does nothing upon destruction.  Optionally can restore the previous binding.
 */
 class Bind
 {
@@ -50,22 +77,68 @@ private:
 	};
 
 	template<typename T>
-	struct Binder: Base
+	struct Binder1: Base
 	{
-		const T &obj;
+		const T *obj;
+
+		Binder1(const T *o):
+			obj(o)
+		{
+			if(obj)
+				obj->bind();
+			else
+				T::unbind();
+		}
+
+		~Binder1()
+		{
+			if(obj)
+				obj->unbind();
+		}
+	};
 
-		Binder(const T &o): obj(o) { obj.bind(); }
-		~Binder() { obj.unbind(); }
+	template<typename T, typename U>
+	struct Binder2: Base
+	{
+		const T *obj;
+		const U *old;
+
+		Binder2(const T *o, const U *l):
+			obj(o),
+			old(l)
+		{
+			if(obj)
+				obj->bind();
+			else
+				T::unbind();
+		}
+
+		~Binder2()
+		{
+			if(old)
+				old->bind();
+			else if(obj)
+				obj->unbind();
+		}
 	};
 
 	Base *binder;
 
 public:
 	template<typename T>
-	Bind(const T &o): binder(new Binder<T>(o)) { }
+	Bind(const T &o, bool r = false):
+		binder(r ? create(&o, T::current()) : create(&o))
+	{ }
+
+	template<typename T>
+	Bind(const T *o, bool r = false):
+		binder(r ? create(o, T::current()) : create(o))
+	{ }
 
 	template<typename T>
-	Bind(const T *o): binder(o ? new Binder<T>(*o) : 0) { if(!o) T::unbind(); }
+	Bind(T *o, bool r = false):
+		binder(r ? create(o, T::current()) : create(o))
+	{ }
 
 private:
 	Bind(const Bind &);
@@ -73,6 +146,15 @@ private:
 
 public:
 	~Bind() { delete binder; }
+
+private:
+	template<typename T>
+	Base *create(const T *o)
+	{ return new Binder1<T>(o); }
+
+	template<typename T, typename U>
+	Base *create(const T *o, const U *l)
+	{ return new Binder2<T, U>(o, l); }
 };
 
 } // namespace GL