/*

Copyright (C) 2015 Andreas Weber <andy.weber.aw@gmail.com>

This file is part of Octave.

Octave is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 3 of the License, or (at your
option) any later version.

Octave is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with Octave; see the file COPYING.  If not, see
<http://www.gnu.org/licenses/>.

This code is based on Brian Pauls' src/osdemos/osdemo.c
from git://anongit.freedesktop.org/mesa/demos

*/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "oct-locbuf.h"
#include "unwind-prot.h"

#include "defun-dld.h"
#include "errwarn.h"
#include "gl-render.h"
#include "gl2ps-renderer.h"
#include "graphics.h"
#include "oct-opengl.h"

#if defined (HAVE_OSMESA_H)
#  include "osmesa.h"
#elif defined (HAVE_GL_OSMESA_H)
#  include "GL/osmesa.h"
#endif

#if defined (HAVE_OSMESA) && defined (HAVE_OPENGL)
static void
close_fcn (FILE *f)
{
  gnulib::fclose (f);
}

static void
reset_visibility (figure::properties *fp)
{
  fp->set_visible ("on");
}
#endif

DEFUN_DLD(__osmesa_print__, args, ,
          "-*- texinfo -*-\n\
@deftypefn  {} {} __osmesa_print__ (@var{h}, @var{file}, @var{term})\n\
@deftypefnx {} {@var{img} =} __osmesa_print__ (@var{h})\n\
Print figure @var{h} using OSMesa and gl2ps for vector formats.\n\
\n\
This is a private internal function.\n\
\n\
The first method calls gl2ps with the appropriate @var{term} and writes\n\
the output of gl2ps to @var{file}.  If the first character of @var{file}\n\
is @qcode{|}, then a process is started and the output of gl2ps is piped\n\
to it.\n\
\n\
Valid options for @var{term}, which can be concatenated in one string, are:\n\
\n\
@table @asis\n\
@item @qcode{eps}, @qcode{pdf}, @qcode{ps}, @qcode{svg}, @qcode{pgf}, @qcode{tex}\n\
Select output format.\n\
\n\
@item @qcode{is2D}\n\
Use GL2PS_SIMPLE_SORT instead of GL2PS_BSP_SORT as Z-depth sorting algorithm.\n\
\n\
@item @qcode{notext}\n\
Don't render text.\n\
@end table\n\
\n\
The second method doesn't use gl2ps and returns a RGB image in @var{img}\n\
instead.\n\
\n\
@end deftypefn")
{
#ifndef HAVE_OSMESA
  err_disabled_feature ("__osmesa_print__", "offscreen rendering with OSMesa");
#else
  int nargin = args.length ();

  if (nargin != 1 && nargin != 3)
    print_usage ();

  if (nargin == 3)
    {
      if (! (args(1).is_string () && args(2).is_string ()))
        error ("__osmesa_print__: FILE and TERM must be strings");

#ifndef HAVE_GL2PS_H
      error ("__osmesa_print__: Octave has been compiled without gl2ps");
#endif
    }

  octave_value_list retval;

  int h = args(0).double_value ();
  graphics_object fobj = gh_manager::get_object (h);
  if (! (fobj && fobj.isa ("figure")))
    error ("__osmesa_print__: H must be a valid figure handle");

  figure::properties& fp =
    dynamic_cast<figure::properties&> (fobj.get_properties ());

  bool internal = true;
  Matrix bb = fp.get_boundingbox (internal);

  GLsizei Width = static_cast<GLsizei> (bb(2));
  GLsizei Height = static_cast<GLsizei> (bb(3));

  // Create an RGBA-mode context, specify Z=16, stencil=0, accum=0 sizes
  OSMesaContext ctx = OSMesaCreateContextExt (OSMESA_RGBA, 16, 0, 0, NULL);
  if (! ctx)
    error ("__osmesa_print__: OSMesaCreateContext failed!\n");

  // Allocate the image buffer
  OCTAVE_LOCAL_BUFFER (GLubyte, buffer, 4 * Width * Height);

  // Bind the buffer to the context and make it current
  if (! OSMesaMakeCurrent (ctx, buffer, GL_UNSIGNED_BYTE, Width, Height))
    error ("__osmesa_print__: OSMesaMakeCurrent failed!\n");

  // Test for a bug in OSMesa with version < 9.0
  //
  // Unfortunately the macros OSMESA_MAJOR_VERSION and OSMESA_MINOR_VERSION
  // weren't updated between many releases and can't be used for detection.
  // (Version 8.0 until 9.1.4 all return MAJOR 6, MINOR 5)
  GLint z, s;
  glGetIntegerv (GL_DEPTH_BITS, &z);
  glGetIntegerv (GL_STENCIL_BITS, &s);
  if (z != 16 || s != 0)
    error ("__osmesa_print__: Depth and stencil doesn't match,"
           " are you sure you are using OSMesa >= 9.0?");

  unwind_protect outer_frame;

  bool v = fp.is_visible ();

  if (v)
    {
      outer_frame.add_fcn (reset_visibility, &fp);

      fp.set_visible ("off");
    }

  if (nargin == 3)
    {
      // use gl2ps
#ifndef HAVE_GL2PS_H
      err_disabled_feature ("__osmesa_print__", "gl2ps");
#else
      std::string file = args(1).string_value ();
      std::string term = args(2).string_value ();

      size_t pos_p = file.find_first_of ("|");
      size_t pos_c = file.find_first_not_of ("| ");

      if (pos_p == std::string::npos && pos_c == std::string::npos)
        error ("__osmesa_print__: empty output ''");
      else if (pos_c == std::string::npos)
        error ("__osmesa_print__: empty pipe '|'");
      else if (pos_p != std::string::npos && pos_p < pos_c)
        {
          // create process and pipe gl2ps output to it
          std::string cmd = file.substr (pos_c);
          gl2ps_print (fobj, cmd, term);
        }
      else
        {
          // write gl2ps output directly to file
          FILE *filep = gnulib::fopen (file.substr (pos_c).c_str (), "w");

          if (! filep)
            error ("__osmesa_print__: Couldn't create file \"%s\"", file.c_str ());

          unwind_protect frame;

          frame.add_fcn (close_fcn, filep);

          gl2ps_renderer rend (filep, term);
          rend.draw (fobj, "");

          // Make sure buffered commands are finished!!!
          glFinish ();
        }
#endif
    }
  else
    {
      // return RGB image
      opengl_renderer rend;
      rend.draw (fobj);

      // Make sure buffered commands are finished!!!
      glFinish ();

      dim_vector dv (4, Width, Height);

      // FIXME: We expect that GLubyte is 1 Byte long.
      // Adapt code if this isn't always true
      assert (sizeof (GLubyte) == 1);
      uint8NDArray img (dv);
      unsigned char *p = reinterpret_cast<unsigned char*>(img.fortran_vec ());
      memcpy (p, buffer, (4 * Width * Height));

      Array<octave_idx_type> perm (dim_vector (3, 1));
      perm(0) = 2;
      perm(1) = 1;
      perm(2) = 0;

      Array<idx_vector> idx (dim_vector (3, 1));

      // Flip Y
      idx(0) = idx_vector::make_range (Height - 1, -1, Height);
      idx(1) = idx_vector::colon;

      // Remove alpha channel
      idx(2) = idx_vector (0, 3);
      retval = octave_value (img.permute (perm). index(idx));
    }

  OSMesaDestroyContext (ctx);

  return retval;
#endif
}

/*
## FIXME: osmesa does not work correctly on Windows platforms.
##        This is not critical, since this facility will mostly be used in
##        the future for generating the images in Octave's own documentation.
##        For the moment, disable these tests on PC's and Macs.
%!testif HAVE_OSMESA, HAVE_GL2PS_H
%! if (isunix ())
%!   h = figure ("visible", "off");
%!   fn = tempname ();
%!   sombrero ();
%!   __osmesa_print__ (h, fn, "svg");
%!   assert (stat (fn).size, 2692270, -0.1);
%!   unlink (fn);
%!   img = __osmesa_print__ (h);
%!   assert (size (img), [get(h, "position")([4, 3]), 3])
%!   ## Use pixel sum per RGB channel as fingerprint
%!   img_fp = squeeze (sum (sum (img), 2));
%!   assert (img_fp, [52942515; 54167797; 56158178], -0.05);
%! endif

%!testif HAVE_OSMESA, HAVE_GL2PS_H
%! if (isunix ())
%!   h = figure ("visible", "off");
%!   fn = tempname ();
%!   plot (sin (0:0.1:2*pi));
%!   __osmesa_print__ (h, fn, "svgis2d");
%!   assert (stat (fn).size, 7438, -0.1);
%!   unlink (fn);
%!   img = __osmesa_print__ (h);
%!   assert (size (img), [get(h, "position")([4, 3]), 3])
%!   ## Use pixel sum per RGB channel as fingerprint
%!   img_fp = squeeze (sum (sum (img), 2));
%!   assert (img_fp, [59281711; 59281711; 59482179], -0.05);
%! endif
*/