/**
 * 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."
 *
 * @file auxBitplaneAttrib.h
 * @author drose
 * @date 2002-03-04
 */

#ifndef AUXBITPLANEATTRIB_H
#define AUXBITPLANEATTRIB_H

#include "pandabase.h"
#include "renderAttrib.h"

class FactoryParams;

/**
 * Modern frame buffers can have 'aux' bitplanes, which are additional
 * bitplanes above and beyond the standard depth and color.  This attrib
 * controls what gets rendered into those additional bitplanes.  It can also
 * affect what goes into the alpha channel of the primary color buffer.
 *
 * ABO_glow: copy the glow map into the alpha channel of the primary frame
 * buffer.  If there is no glow map, set it to zero.  Caveat: it is not
 * possible to write glow or depth values to the framebuffer alpha channel at
 * the same time as using alpha blending or alpha testing.  Any attempt to use
 * transparency, blending, or alpha testing will cause this flag to be
 * overridden.
 *
 * ABO_aux_normal: put the camera-space normal into the into the R,G
 * components of the first auxiliary bitplane.
 *
 * ABO_aux_modelz: put the clip-space Z coordinate of the center of the model
 * (after perspective divide) into the B channel of the first auxiliary
 * bitplane.
 *
 * ABO_aux_glow: put a copy of the glow map into the alpha channel of the
 * first auxiliary bitplane.  If there is no glow map, set it to zero.
 *
 * AuxBitplaneAttrib is relevant only when shader generation is enabled.
 * Otherwise, it has no effect.
 *
 */
class EXPCL_PANDA_PGRAPH AuxBitplaneAttrib : public RenderAttrib {
private:
  INLINE AuxBitplaneAttrib(int outputs);

PUBLISHED:
  enum AuxBitplaneOutput {
    ABO_glow = 1,

    ABO_aux_normal = 2,
    ABO_aux_glow = 4,
  };
  static CPT(RenderAttrib) make();
  static CPT(RenderAttrib) make(int outputs);
  static CPT(RenderAttrib) make_default();

  INLINE int get_outputs() const;

PUBLISHED:
  MAKE_PROPERTY(outputs, get_outputs);

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

protected:
  virtual int compare_to_impl(const RenderAttrib *other) const;
  virtual size_t get_hash_impl() const;

private:
  int _outputs;

  static CPT(RenderAttrib) _default;

PUBLISHED:
  static int get_class_slot() {
    return _attrib_slot;
  }
  virtual int get_slot() const {
    return get_class_slot();
  }
  MAKE_PROPERTY(class_slot, get_class_slot);

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() {
    RenderAttrib::init_type();
    register_type(_type_handle, "AuxBitplaneAttrib",
                  RenderAttrib::get_class_type());
    _attrib_slot = register_slot(_type_handle, 100, new AuxBitplaneAttrib(0));
  }
  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;
  static int _attrib_slot;
};

#include "auxBitplaneAttrib.I"

#endif