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panda/src/gobj/orthographicLens.cxx

Go to the documentation of this file.

// Filename: orthographicLens.cxx
// Created by:  mike (18Feb99)
//
////////////////////////////////////////////////////////////////////
//
// PANDA 3D SOFTWARE
// Copyright (c) 2001, 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://www.panda3d.org/license.txt .
//
// To contact the maintainers of this program write to
// panda3d@yahoogroups.com .
//
////////////////////////////////////////////////////////////////////

#include "orthographicLens.h"
#include "indent.h"

TypeHandle OrthographicLens::_type_handle;


////////////////////////////////////////////////////////////////////
//     Function: OrthographicLens::make_copy
//       Access: Public, Virtual
//  Description: Allocates a new Lens just like this one.
////////////////////////////////////////////////////////////////////
PT(Lens) OrthographicLens::
make_copy() const {
  return new OrthographicLens(*this);
}

////////////////////////////////////////////////////////////////////
//     Function: OrthographicLens::is_linear
//       Access: Published, Virtual
//  Description: Returns true if the lens represents a linear
//               projection (e.g. PerspectiveLens, OrthographicLens),
//               and therefore there is a valid matrix returned by
//               get_projection_mat(), or false otherwise.
////////////////////////////////////////////////////////////////////
bool OrthographicLens::
is_linear() const {
  return true;
}

////////////////////////////////////////////////////////////////////
//     Function: OrthographicLens::write
//       Access: Public, Virtual
//  Description: 
////////////////////////////////////////////////////////////////////
void OrthographicLens::
write(ostream &out, int indent_level) const {
  indent(out, indent_level) << get_type() << " film size = " << get_film_size() << "\n";
}

////////////////////////////////////////////////////////////////////
//     Function: OrthographicLens::compute_projection_mat
//       Access: Protected, Virtual
//  Description: Computes the complete transformation matrix from 3-d
//               point to 2-d point, if the lens is linear.
////////////////////////////////////////////////////////////////////
void OrthographicLens::
compute_projection_mat() {
  CoordinateSystem cs = _cs;
  if (cs == CS_default) {
    cs = default_coordinate_system;
  }

  float a = 2.0f / (_far_distance - _near_distance);
  float b = -(_far_distance + _near_distance) / (_far_distance - _near_distance);

  LMatrix4f canonical;
  switch (cs) {
  case CS_zup_right:
    canonical.set(1.0f,  0.0f,  0.0f,  0.0f,
                  0.0f,  0.0f,     a,  0.0f,
                  0.0f,  1.0f,  0.0f,  0.0f,
                  0.0f,  0.0f,     b,  1.0f);
    break;

  case CS_yup_right:
    canonical.set(1.0f,  0.0f,  0.0f,  0.0f,
                  0.0f,  1.0f,  0.0f,  0.0f,
                  0.0f,  0.0f,    -a,  0.0f,
                  0.0f,  0.0f,     b,  1.0f);
    break;

  case CS_zup_left:
    canonical.set(1.0f,  0.0f,  0.0f,  0.0f,
                  0.0f,  0.0f,    -a,  0.0f,
                  0.0f,  1.0f,  0.0f,  0.0f,
                  0.0f,  0.0f,     b,  1.0f);
    break;

  case CS_yup_left:
    canonical.set(1.0f,  0.0f,  0.0f,  0.0f,
                  0.0f,  1.0f,  0.0f,  0.0f,
                  0.0f,  0.0f,     a,  0.0f,
                  0.0f,  0.0f,     b,  1.0f);
    break;

  default:
    gobj_cat.error()
      << "Invalid coordinate system " << (int)cs << " in PerspectiveLens!\n";
    canonical = LMatrix4f::ident_mat();
  }


  _projection_mat = get_lens_mat_inv() * canonical * get_film_mat();
  adjust_comp_flags(CF_projection_mat_inv, 
                    CF_projection_mat);
}

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