/* This file is an image processing operation for GEGL

 *

 * GEGL is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 3 of the License, or (at your option) any later version.

 *

 * GEGL 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

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with GEGL; if not, see <http://www.gnu.org/licenses/>.

 *

 * Copyright 2006 Øyvind Kolås <pippin@gimp.org>

 */

#include "config.h"

#include <glib/gi18n-lib.h>

#ifdef GEGL_CHANT_PROPERTIES

gegl_chant_double(real, _("Real"),      -200.0, 200.0, -1.77,

                  _("Real coordinate"))

gegl_chant_double(img,  _("Imaginary"), -200.0, 200.0, 0.0,

                  _("Imaginary coordinate"))

gegl_chant_double(level, _("Level"), -200.0, 200.0, 3.5,

                  _("Water level"))

gegl_chant_int (maxiter, _("Iterations"), 0, 512, 128,

                _("Maximum number of iterations"))

#else

#define GEGL_CHANT_TYPE_SOURCE

#define GEGL_CHANT_C_FILE           "mandelbrot.c"

#include "gegl-chant.h"

static gfloat

mandel_calc(GeglChantO *o, gfloat x, gfloat y)

{

  gfloat fViewRectReal = o->real;

  gfloat fViewRectImg  = o->img;

  gfloat fMagLevel     = o->level;

  gfloat fCReal = fViewRectReal + x * fMagLevel;

  gfloat fCImg  = fViewRectImg + y * fMagLevel;

  gfloat fZReal = fCReal;

  gfloat fZImg  = fCImg;

        gint n;

        for (n=0;n<o->maxiter;n++)

          {

                gfloat fZRealSquared = fZReal * fZReal;

                gfloat fZImgSquared = fZImg * fZImg;

                if (fZRealSquared + fZImgSquared > 4)

                        return 1.0*n/(o->maxiter);

/*                -- z = z^2 + c*/

                fZImg = 2 * fZReal * fZImg + fCImg;

                fZReal = fZRealSquared - fZImgSquared + fCReal;

          }

        return 1.0;

}

static void prepare (GeglOperation *operation)

{

  gegl_operation_set_format (operation, "output", babl_format ("Y float"));

}

static GeglRectangle

get_bounding_box (GeglOperation *operation)

{

  GeglRectangle result = {-256,-256, 1024, 1024};

  return result;

}

static gboolean

process (GeglOperation       *operation,

         GeglBuffer          *output,

         const GeglRectangle *result,

         gint                 level)

{

  GeglChantO *o = GEGL_CHANT_PROPERTIES (operation);

  gfloat     *buf;

  gint        pxsize;

  g_object_get (output, "px-size", &pxsize, NULL);

  buf = g_malloc (result->width * result->height * pxsize);

    {

      gfloat *dst = buf;

      gint y;

      for (y=0; y < result->height; y++)

        {

          gint x;

          for (x=0; x < result->width ; x++)

            {

              gfloat value;

              gfloat nx,ny;

              nx = (x + result->x);

              ny = (y + result->y);

              nx = (nx/512);

              ny = (ny/512);

              value = mandel_calc (o, nx, ny);

              *dst++ = value;

            }

        }

    }

  gegl_buffer_set (output, NULL, 0, babl_format ("Y float"), buf,

                   GEGL_AUTO_ROWSTRIDE);

  g_free (buf);

  return  TRUE;

}

static void

gegl_chant_class_init (GeglChantClass *klass)

{

  GeglOperationClass       *operation_class;

  GeglOperationSourceClass *source_class;

  operation_class = GEGL_OPERATION_CLASS (klass);

  source_class    = GEGL_OPERATION_SOURCE_CLASS (klass);

  source_class->process = process;

  operation_class->prepare = prepare;

  operation_class->get_bounding_box = get_bounding_box;

  gegl_operation_class_set_keys (operation_class,

    "name"        , "gegl:mandelbrot",

    "categories"  , "render",

    "description" , _("Mandelbrot set renderer"),

    NULL);

}

#endif