// Filename: antialiasAttrib.cxx
// Created by:  drose (26Jan05)
//
////////////////////////////////////////////////////////////////////
//
// 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 .
//
////////////////////////////////////////////////////////////////////

#include "antialiasAttrib.h"
#include "graphicsStateGuardianBase.h"
#include "dcast.h"
#include "bamReader.h"
#include "bamWriter.h"
#include "datagram.h"
#include "datagramIterator.h"

TypeHandle AntialiasAttrib::_type_handle;

////////////////////////////////////////////////////////////////////
//     Function: AntialiasAttrib::make
//       Access: Published, Static
//  Description: Constructs a new AntialiasAttrib object.
//
//               The mode should be either M_none, M_auto, or a union
//               of any or all of M_point, M_line, M_polygon, and
//               M_multisample.  Also, in addition to the above
//               choices, it may include either of M_better of
//               M_faster to specify a performance/quality tradeoff
//               hint.
//
//               If M_none is specified, no antialiasing is performed.  
//
//               If M_multisample is specified, it means to use the
//               special framebuffer multisample bits for
//               antialiasing, if it is available.  If so, the
//               M_point, M_line, and M_polygon modes are ignored.
//               This advanced antialiasing mode is only available on
//               certain graphics hardware.  If it is not available,
//               the M_multisample bit is ignored (and the other modes
//               may be used instead, if specified).
//
//               M_point, M_line, and/or M_polygon specify
//               per-primitive smoothing.  When enabled, M_point and
//               M_line may force transparency on.  M_polygon requires
//               a frame buffer that includes an alpha channel, and it
//               works best if the primitives are sorted
//               front-to-back.
//
//               If M_auto is specified, M_multisample is selected if
//               it is available, otherwise M_polygon is selected,
//               unless drawing lines or points, in which case M_line
//               or M_point is selected (these two generally produce
//               better results than M_multisample)
////////////////////////////////////////////////////////////////////
CPT(RenderAttrib) AntialiasAttrib::
make(unsigned short mode) {
  AntialiasAttrib *attrib = new AntialiasAttrib(mode);
  return return_new(attrib);
}

////////////////////////////////////////////////////////////////////
//     Function: AntialiasAttrib::issue
//       Access: Public, Virtual
//  Description: Calls the appropriate method on the indicated GSG
//               to issue the graphics commands appropriate to the
//               given attribute.  This is normally called
//               (indirectly) only from
//               GraphicsStateGuardian::set_state() or modify_state().
////////////////////////////////////////////////////////////////////
void AntialiasAttrib::
issue(GraphicsStateGuardianBase *gsg) const {
  gsg->issue_antialias(this);
}

////////////////////////////////////////////////////////////////////
//     Function: AntialiasAttrib::output
//       Access: Public, Virtual
//  Description: 
////////////////////////////////////////////////////////////////////
void AntialiasAttrib::
output(ostream &out) const {
  out << get_type() << ":";
  
  int type = get_mode_type();
  char sep = ' ';

  if (type == M_none) {
    out << " none";

  } else if (type == M_auto) {
    out << " auto";

  } else {
    if ((_mode & M_point) != 0) {
      out << sep << "point";
      sep = '|';
    }
    if ((_mode & M_line) != 0) {
      out << sep << "line";
      sep = '|';
    }
    if ((_mode & M_polygon) != 0) {
      out << sep << "polygon";
      sep = '|';
    }
    if ((_mode & M_auto) != 0) {
      out << sep << "best";
      sep = '|';
    }
  }

  if ((_mode & M_faster) != 0) {
    out << sep << "faster";
    sep = '|';
  }
  if ((_mode & M_better) != 0) {
    out << sep << "better";
    sep = '|';
  }
}

////////////////////////////////////////////////////////////////////
//     Function: AntialiasAttrib::compare_to_impl
//       Access: Protected, Virtual
//  Description: Intended to be overridden by derived AntialiasAttrib
//               types to return a unique number indicating whether
//               this AntialiasAttrib is equivalent to the other one.
//
//               This should return 0 if the two AntialiasAttrib objects
//               are equivalent, a number less than zero if this one
//               should be sorted before the other one, and a number
//               greater than zero otherwise.
//
//               This will only be called with two AntialiasAttrib
//               objects whose get_type() functions return the same.
////////////////////////////////////////////////////////////////////
int AntialiasAttrib::
compare_to_impl(const RenderAttrib *other) const {
  const AntialiasAttrib *ta;
  DCAST_INTO_R(ta, other, 0);
  if (_mode != ta->_mode) {
    return (int)_mode - (int)ta->_mode;
  }
  return 0;
}

////////////////////////////////////////////////////////////////////
//     Function: AntialiasAttrib::compose_impl
//       Access: Protected, Virtual
//  Description: Intended to be overridden by derived RenderAttrib
//               types to specify how two consecutive RenderAttrib
//               objects of the same type interact.
//
//               This should return the result of applying the other
//               RenderAttrib to a node in the scene graph below this
//               RenderAttrib, which was already applied.  In most
//               cases, the result is the same as the other
//               RenderAttrib (that is, a subsequent RenderAttrib
//               completely replaces the preceding one).  On the other
//               hand, some kinds of RenderAttrib (for instance,
//               ColorTransformAttrib) might combine in meaningful
//               ways.
////////////////////////////////////////////////////////////////////
CPT(RenderAttrib) AntialiasAttrib::
compose_impl(const RenderAttrib *other) const {
  const AntialiasAttrib *ta;
  DCAST_INTO_R(ta, other, 0);

  unsigned short mode_type;
  unsigned short mode_quality;

  if (ta->get_mode_type() == M_none || ta->get_mode_type() == M_auto ||
      get_mode_type() == M_auto) {
    // These two special types don't combine: if one of these modes is
    // involved, the lower attrib wins.
    mode_type = ta->get_mode_type();

  } else {
    // Otherwise, the both modes reflect an explicit setting.  In that
    // case, these modes combine in the sensible way, as a union of
    // bits.
    mode_type = get_mode_type() | ta->get_mode_type();
  }

  if (ta->get_mode_quality() != 0) {
    // If any quality is specified on the lower attrib, it wins.
    mode_quality = ta->get_mode_quality();
  } else {
    // Otherwise, the upper quality wins.
    mode_quality = get_mode_quality();
  }

  return make(mode_type | mode_quality);
}

////////////////////////////////////////////////////////////////////
//     Function: AntialiasAttrib::make_default_impl
//       Access: Protected, Virtual
//  Description: Intended to be overridden by derived AntialiasAttrib
//               types to specify what the default property for a
//               AntialiasAttrib of this type should be.
//
//               This should return a newly-allocated AntialiasAttrib of
//               the same type that corresponds to whatever the
//               standard default for this kind of AntialiasAttrib is.
////////////////////////////////////////////////////////////////////
RenderAttrib *AntialiasAttrib::
make_default_impl() const {
  return new AntialiasAttrib(M_none);
}

////////////////////////////////////////////////////////////////////
//     Function: AntialiasAttrib::register_with_read_factory
//       Access: Public, Static
//  Description: Tells the BamReader how to create objects of type
//               AntialiasAttrib.
////////////////////////////////////////////////////////////////////
void AntialiasAttrib::
register_with_read_factory() {
  BamReader::get_factory()->register_factory(get_class_type(), make_from_bam);
}

////////////////////////////////////////////////////////////////////
//     Function: AntialiasAttrib::write_datagram
//       Access: Public, Virtual
//  Description: Writes the contents of this object to the datagram
//               for shipping out to a Bam file.
////////////////////////////////////////////////////////////////////
void AntialiasAttrib::
write_datagram(BamWriter *manager, Datagram &dg) {
  RenderAttrib::write_datagram(manager, dg);

  dg.add_uint16(_mode);
}

////////////////////////////////////////////////////////////////////
//     Function: AntialiasAttrib::make_from_bam
//       Access: Protected, Static
//  Description: This function is called by the BamReader's factory
//               when a new object of type AntialiasAttrib is encountered
//               in the Bam file.  It should create the AntialiasAttrib
//               and extract its information from the file.
////////////////////////////////////////////////////////////////////
TypedWritable *AntialiasAttrib::
make_from_bam(const FactoryParams &params) {
  AntialiasAttrib *attrib = new AntialiasAttrib(M_none);
  DatagramIterator scan;
  BamReader *manager;

  parse_params(params, scan, manager);
  attrib->fillin(scan, manager);

  return attrib;
}

////////////////////////////////////////////////////////////////////
//     Function: AntialiasAttrib::fillin
//       Access: Protected
//  Description: This internal function is called by make_from_bam to
//               read in all of the relevant data from the BamFile for
//               the new AntialiasAttrib.
////////////////////////////////////////////////////////////////////
void AntialiasAttrib::
fillin(DatagramIterator &scan, BamReader *manager) {
  RenderAttrib::fillin(scan, manager);

  _mode = scan.get_uint16();
}
