/* 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 2011 Audrey Mandet <mandet.audrey@gmail.com>

 * Copyright (c) 1997 Eric L. Hernes (erich@rrnet.com)

 */

#include "config.h"

#include <glib/gi18n-lib.h>

#include <math.h>

#ifdef GEGL_CHANT_PROPERTIES

gegl_chant_double_ui (x, _("X"), -G_MAXDOUBLE, G_MAXDOUBLE, 0.0, 0.0, 1024.0, 1.0,

                   _("X coordinate of the center of the waves"))

gegl_chant_double_ui (y, _("Y"), -G_MAXDOUBLE, G_MAXDOUBLE, 0.0, 0.0, 1024.0, 1.0,

                   _("Coordinate y of the center of the waves"))

gegl_chant_double (amplitude, _("Amplitude"), 0.0, 1000.0, 25.0,

                   _("Amplitude of the ripple"))

gegl_chant_double (period, _("Period"), 0.0, 1000.0, 200.0,

                   _("Period of the ripple"))

gegl_chant_double (phi, _("Phase shift"), -1.0, 1.0, 0.0,

                   _("Phase shift"))

gegl_chant_enum (sampler_type, _("Sampler"), GeglSamplerType, GEGL_TYPE_SAMPLER_TYPE,

                 GEGL_SAMPLER_CUBIC, _("Sampler used internally"))

#else

#define GEGL_CHANT_TYPE_AREA_FILTER

#define GEGL_CHANT_C_FILE       "waves.c"

#include "gegl-chant.h"

#include <stdio.h>

#include <math.h>

static void prepare (GeglOperation *operation)

{

  GeglChantO              *o;

  GeglOperationAreaFilter *op_area;

  op_area = GEGL_OPERATION_AREA_FILTER (operation);

  o       = GEGL_CHANT_PROPERTIES (operation);

  op_area->left   = o->amplitude;

  op_area->right  = o->amplitude;

  op_area->top    = o->amplitude;

  op_area->bottom = o->amplitude;

  gegl_operation_set_format (operation, "input",

                             babl_format ("RGBA float"));

  gegl_operation_set_format (operation, "output",

                             babl_format ("RGBA float"));

}

static gboolean

process (GeglOperation       *operation,

         GeglBuffer          *input,

         GeglBuffer          *output,

         const GeglRectangle *result,

         gint                 level)

{

  GeglChantO *o                    = GEGL_CHANT_PROPERTIES (operation);

  gint x = result->x; /* initial x                   */

  gint y = result->y; /*           and y coordinates */

  gfloat *dst_buf = g_slice_alloc (result->width * result->height * 4 * sizeof(gfloat));

  gfloat *out_pixel = dst_buf;

  GeglSampler *sampler = gegl_buffer_sampler_new (input,

                                                  babl_format ("RGBA float"),

                                                  o->sampler_type);

  gint n_pixels = result->width * result->height;

  while (n_pixels--)

    {

      gdouble coordsx = 0.0;

      gdouble coordsy = 0.0;

      gdouble radius = 0.0;

      gdouble shift = 0.0;

      gdouble ux = 0.0; /* unit vector of the radius */

      gdouble uy = 0.0;

      gdouble vx = 0.0; /* orthogonal vector of u */

      gdouble vy = 0.0;

      gdouble dx = 0.0;

      gdouble dy = 0.0;

      dx = (gdouble)x-o->x;

      dy = (gdouble)y-o->y;

      radius = sqrt( dx * dx + dy * dy );

      shift = o->amplitude * sin(2.0 * G_PI * radius / o->period + 2.0 * G_PI * o->phi);

      ux = dx / radius;

      uy = dy / radius;

      vx = -uy;

      vy = ux;

      coordsx = x + shift * vx;

      coordsy = y + shift * vy;

      gegl_sampler_get (sampler,

                        coordsx,

                        coordsy,

                        NULL,

                        out_pixel);

      out_pixel += 4;

      /* update x and y coordinates */

      x++;

      if (x>=result->x + result->width)

        {

          x=result->x;

          y++;

        }

    }

  gegl_buffer_set (output, result, 0, babl_format ("RGBA float"), dst_buf, GEGL_AUTO_ROWSTRIDE);

  g_slice_free1 (result->width * result->height * 4 * sizeof(gfloat), dst_buf);

  g_object_unref (sampler);

  return  TRUE;

}

static void

gegl_chant_class_init (GeglChantClass *klass)

{

  GeglOperationClass       *operation_class;

  GeglOperationFilterClass *filter_class;

  operation_class = GEGL_OPERATION_CLASS (klass);

  filter_class    = GEGL_OPERATION_FILTER_CLASS (klass);

  filter_class->process    = process;

  operation_class->prepare = prepare;

  gegl_operation_class_set_keys (operation_class,

    "name"       , "gegl:waves",

    "categories" , "distort",

    "description", _("Transform the buffer with waves"),

    NULL);

}

#endif