Rearrange soucre files into subdirectories

[libs/gl.git] / source / core / bindable.h

diff --git a/source/core/bindable.h b/source/core/bindable.h
new file mode 100644 (file)
index 0000000..b2634ea
--- /dev/null
+++ b/source/core/bindable.h
@@ -0,0 +1,225 @@
+#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
+{
+protected:
+       static const T *cur_obj;
+
+       Bindable() { }
+       ~Bindable() { if(cur_obj==this) T::unbind(); }
+
+       static bool set_current(const T *obj)
+       {
+               if(obj==cur_obj)
+                       return false;
+
+               cur_obj = obj;
+               return true;
+       }
+
+public:
+       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>
+{
+       friend class Bindable<T>;
+
+protected:
+       BindableWithDefault() { }
+       ~BindableWithDefault() { if(this==&default_object()) Bindable<T>::set_current(0); }
+
+public:
+       static const T *current()
+       {
+               if(!Bindable<T>::cur_obj)
+                       Bindable<T>::cur_obj = &default_object();
+               return Bindable<T>::cur_obj;
+       }
+
+       static void unbind()
+       {
+               if(Bindable<T>::cur_obj)
+                       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.
+*/
+class Bind
+{
+private:
+       typedef void CleanupFunc(int);
+
+       int slot;
+       CleanupFunc *cleanup;
+
+public:
+       template<typename T>
+       Bind(T *o) { init(o); }
+
+       template<typename T>
+       Bind(const T *o) { init(o); }
+
+       template<typename T>
+       Bind(const T &o) { init(&o); }
+
+       template<typename T, typename S>
+       Bind(T *o, S s) { init(o, s); }
+
+       template<typename T, typename S>
+       Bind(const T *o, S s) { init(o, s); }
+
+       template<typename T, typename S>
+       Bind(const T &o, S s) { init(&o, s); }
+
+private:
+       template<typename T>
+       void init(const T *o)
+       {
+               cleanup = (o ? static_cast<CleanupFunc *>(&unbind<T>) : 0);
+               slot = 0;
+               if(o)
+                       o->bind();
+               else
+                       T::unbind();
+       }
+
+       template<typename T, typename S>
+       void init(const T *o, S s)
+       {
+               cleanup = (o ? static_cast<CleanupFunc *>(&unbind_from<T, S>) : 0);
+               slot = s;
+               if(o)
+                       o->bind_to(s);
+               else
+                       T::unbind_from(s);
+       }
+
+public:
+       ~Bind()
+       { if(cleanup) cleanup(slot); }
+
+private:
+       template<typename T>
+       static void unbind(int)
+       { T::unbind(); }
+
+       template<typename T, typename S>
+       static void unbind_from(int s)
+       { T::unbind_from(static_cast<S>(s)); }
+};
+
+
+/**
+Similar to Bind, but restores previous binding upon destruction.
+*/
+class BindRestore
+{
+private:
+       typedef void CleanupFunc(const void *, int);
+
+       const void *old;
+       int slot;
+       CleanupFunc *cleanup;
+
+public:
+       template<typename T>
+       BindRestore(T *o) { init(o); }
+
+       template<typename T>
+       BindRestore(const T *o) { init(o); }
+
+       template<typename T>
+       BindRestore(const T &o) { init(&o); }
+
+       template<typename T, typename S>
+       BindRestore(T *o, S s) { init(o, s); }
+
+       template<typename T, typename S>
+       BindRestore(const T *o, S s) { init(o, s); }
+
+       template<typename T, typename S>
+       BindRestore(const T &o, S s) { init(&o, s); }
+
+private:
+       template<typename T>
+       void init(T *o)
+       {
+               old = T::current();
+               slot = 0;
+               cleanup = (o!=old ? static_cast<CleanupFunc *>(&restore<T>) : 0);
+               if(o)
+                       o->bind();
+               else if(old)
+                       T::unbind();
+       }
+
+       template<typename T, typename S>
+       void init(T *o, S s)
+       {
+               old = T::current(s);
+               slot = s;
+               cleanup = (o!=old ? static_cast<CleanupFunc *>(&restore_to<T, S>) : 0);
+               if(o)
+                       o->bind_to(s);
+               else if(old)
+                       T::unbind_from(s);
+       }
+
+public:
+       ~BindRestore()
+       { if(cleanup) cleanup(old, slot); }
+
+private:
+       template<typename T>
+       static void restore(const void *o, int)
+       {
+               if(o)
+                       reinterpret_cast<const T *>(o)->bind();
+               else
+                       T::unbind();
+       }
+
+       template<typename T, typename S>
+       static void restore_to(const void *o, int si)
+       {
+               S s = static_cast<S>(si);
+               if(o)
+                       reinterpret_cast<const T *>(o)->bind_to(s);
+               else
+                       T::unbind_from(s);
+       }
+};
+
+} // namespace GL
+} // namespace Msp
+
+#endif