// Filename: compassEffect.h
// Created by:  drose (16Jul02)
//
////////////////////////////////////////////////////////////////////
//
// PANDA 3D SOFTWARE
// Copyright (c) 2001 - 2004, Disney Enterprises, Inc.  All rights reserved
//
// All use of this software is subject to the terms of the Panda 3d
// Software license.  You should have received a copy of this license
// along with this source code; you will also find a current copy of
// the license at http://etc.cmu.edu/panda3d/docs/license/ .
//
// To contact the maintainers of this program write to
// panda3d-general@lists.sourceforge.net .
//
////////////////////////////////////////////////////////////////////

#ifndef COMPASSEFFECT_H
#define COMPASSEFFECT_H

#include "pandabase.h"

#include "renderEffect.h"
#include "luse.h"
#include "nodePath.h"

////////////////////////////////////////////////////////////////////
//       Class : CompassEffect
// Description : A CompassEffect causes a node to inherit its rotation
//               (or pos or scale, if specified) from some other
//               reference node in the graph, or more often from the
//               root.
//
//               In its purest form, a CompassEffect is used to keep
//               the node's rotation fixed relative to the top of the
//               scene graph, despite other transforms that may exist
//               above the node.  Hence the name: the node behaves
//               like a magnetic compass, always pointing in the same
//               direction.
//
//               As an couple of generalizing extensions, the
//               CompassEffect may also be set up to always orient its
//               node according to some other reference node than the
//               root of the scene graph.  Furthermore, it may
//               optionally adjust any of pos, rotation, or scale,
//               instead of necessarily rotation; and it may adjust
//               individual pos and scale components.  (Rotation may
//               not be adjusted on an individual component basis;
//               that's just asking for trouble.)
//
//               Be careful when using the pos and scale modes.  In
//               these modes, it's possible for the CompassEffect to
//               move its node far from its normal bounding volume,
//               causing culling to fail.  If this is an issue, you
//               may need to explicitly set a large (or infinite)
//               bounding volume on the effect node.
////////////////////////////////////////////////////////////////////
class EXPCL_PANDA CompassEffect : public RenderEffect {
private:
  INLINE CompassEffect();

PUBLISHED:
  enum Properties {
    P_x     = 0x001,
    P_y     = 0x002,
    P_z     = 0x004,
    P_pos   = 0x007,
    P_rot   = 0x008,
    P_sx    = 0x010,
    P_sy    = 0x020,
    P_sz    = 0x040,
    P_scale = 0x070,
    P_all   = 0x07f,
  };
  static CPT(RenderEffect) make(const NodePath &reference, 
                                int properties = P_rot);

  INLINE const NodePath &get_reference() const;
  INLINE int get_properties() const;

public:
  virtual bool safe_to_transform() const;
  virtual void output(ostream &out) const;

  virtual bool has_cull_callback() const;
  virtual void cull_callback(CullTraverser *trav, CullTraverserData &data,
                             CPT(TransformState) &node_transform,
                             CPT(RenderState) &node_state) const;

protected:
  virtual int compare_to_impl(const RenderEffect *other) const;

private:
  NodePath _reference;
  int _properties;

public:
  static void register_with_read_factory();
  virtual void write_datagram(BamWriter *manager, Datagram &dg);

protected:
  static TypedWritable *make_from_bam(const FactoryParams &params);
  void fillin(DatagramIterator &scan, BamReader *manager);
  
public:
  static TypeHandle get_class_type() {
    return _type_handle;
  }
  static void init_type() {
    RenderEffect::init_type();
    register_type(_type_handle, "CompassEffect",
                  RenderEffect::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 "compassEffect.I"

#endif

