// Filename: queryContext.h
// Created by:  drose (27Mar06)
//
////////////////////////////////////////////////////////////////////
//
// PANDA 3D SOFTWARE
// Copyright (c) Carnegie Mellon University.  All rights reserved.
//
// All use of this software is subject to the terms of the revised BSD
// license.  You should have received a copy of this license along
// with this source code in a file named "LICENSE."
//
////////////////////////////////////////////////////////////////////

#ifndef QUERYCONTEXT_H
#define QUERYCONTEXT_H

#include "pandabase.h"
#include "typedReferenceCount.h"

class PreparedGraphicsObjects;

////////////////////////////////////////////////////////////////////
//       Class : QueryContext
// Description : This is a base class for queries that might require a
//               round-trip to the graphics engine.  The idea is that
//               when you ask the GSG to make a particular query, it
//               returns a QueryContext, which does not necessarily
//               have the answer right away (but it will eventually).
//
//               Unlike SavedContext, QueryContext is
//               reference-counted.  It removes itself from the GSG
//               when the last reference goes away.  You're
//               responsible for keeping the pointer to the
//               QueryContext as long as you are interested in the
//               answer.
////////////////////////////////////////////////////////////////////
class EXPCL_PANDA_GOBJ QueryContext : public TypedReferenceCount {
public:
  INLINE QueryContext();
  virtual ~QueryContext();

  virtual bool is_answer_ready() const=0;
  virtual void waiting_for_answer();

public:
  static TypeHandle get_class_type() {
    return _type_handle;
  }
  static void init_type() {
    TypedReferenceCount::init_type();
    register_type(_type_handle, "QueryContext",
                  TypedReferenceCount::get_class_type());
  }
  virtual TypeHandle get_type() const {
    return get_class_type();
  }
  virtual TypeHandle force_init_type() {init_type(); return get_class_type();}

private:
  static TypeHandle _type_handle;
};

#include "queryContext.I"

#endif