/* 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>

/* Followed by this #if ... */

#ifdef GEGL_CHANT_PROPERTIES

/* ... are the properties of the filter, these are all scalar values

 * (doubles), the the parameters are:

 *       property name,   min,   max, default, "description of property"

 */

gegl_chant_double_ui (contrast, _("Contrast"), -5.0, 5.0, 1.0, 0.0, 2.0, 1.0,

                   _("Range scale factor"))

gegl_chant_double_ui (brightness, _("Brightness"), -3.0, 3.0, 0.0, -1.0, 1.0, 1.0,

                   _("Amount to increase brightness"))

/* this will create the instance structure for our use, and register the

 * property with the given ranges, default values and a comment for the

 * documentation/tooltip.

 */

#else

/* Specify the base class we're building our operation on, the base

 * class provides a lot of the legwork so we do not have to. For

 * brightness contrast the best base class is the POINT_FILTER base

 * class.

 */

#define GEGL_CHANT_TYPE_POINT_FILTER

/* We specify the file we're in, this is needed to make the code

 * generation for the properties work.

 */

#define GEGL_CHANT_C_FILE       "brightness-contrast.c"

/* Including gegl-chant.h creates most of the GObject boiler plate

 * needed, creating a GeglChant instance structure a GeglChantClass

 * structure for our operation, as well as the needed code to register

 * our new gobject with GEGL.

 */

#include "gegl-chant.h"

/* prepare() is called on each operation providing data to a node that

 * is requested to provide a rendered result. When prepare is called

 * all properties are known. For brightness contrast we use this

 * opportunity to dictate the formats of the input and output buffers.

 */

static void prepare (GeglOperation *operation)

{

  gegl_operation_set_format (operation, "input", babl_format ("RGBA float"));

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

}

/* For GeglOperationPointFilter subclasses, we operate on linear

 * buffers with a pixel count.

 */

static gboolean

process (GeglOperation       *op,

         void                *in_buf,

         void                *out_buf,

         glong                n_pixels,

         const GeglRectangle *roi,

         gint                 level)

{

  /* Retrieve a pointer to GeglChantO structure which contains all the

   * chanted properties

   */

  GeglChantO *o = GEGL_CHANT_PROPERTIES (op);

  gfloat     * GEGL_ALIGNED in_pixel;

  gfloat     * GEGL_ALIGNED out_pixel;

  gfloat      brightness, contrast;

  glong       i;

  in_pixel   = in_buf;

  out_pixel  = out_buf;

  brightness = o->brightness;

  contrast   = o->contrast;

  for (i=0; i

    {

      out_pixel[0] = (in_pixel[0] - 0.5f) * contrast + brightness + 0.5;

      out_pixel[1] = (in_pixel[1] - 0.5f) * contrast + brightness + 0.5;

      out_pixel[2] = (in_pixel[2] - 0.5f) * contrast + brightness + 0.5;

      out_pixel[3] = in_pixel[3]; /* copy the alpha */

      in_pixel  += 4;

      out_pixel += 4;

    }

  return TRUE;

}

#include "opencl/gegl-cl.h"

static const char* kernel_source =

"__kernel void kernel_bc(__global const float4     *in,         \n"

"                        __global       float4     *out,        \n"

"                        float brightness,                      \n"

"                        float contrast)                        \n"

"{                                                              \n"

"  int gid = get_global_id(0);                                  \n"

"  float4 in_v  = in[gid];                                      \n"

"  float4 out_v;                                                \n"

"  out_v.xyz = (in_v.xyz - 0.5f) * contrast + brightness + 0.5f;\n"

"  out_v.w   =  in_v.w;                                         \n"

"  out[gid]  =  out_v;                                          \n"

"}                                                              \n";

static gegl_cl_run_data *cl_data = NULL;

/* OpenCL processing function */

static cl_int

cl_process (GeglOperation       *op,

            cl_mem               in_tex,

            cl_mem               out_tex,

            size_t               global_worksize,

            const GeglRectangle *roi,

            int                  level)

{

  /* Retrieve a pointer to GeglChantO structure which contains all the

   * chanted properties

   */

  GeglChantO *o = GEGL_CHANT_PROPERTIES (op);

  gfloat brightness = o->brightness;

  gfloat contrast   = o->contrast;

  cl_int cl_err = 0;

  if (!cl_data)

    {

      const char *kernel_name[] = {"kernel_bc", NULL};

      cl_data = gegl_cl_compile_and_build (kernel_source, kernel_name);

    }

  if (!cl_data) return 1;

  cl_err |= gegl_clSetKernelArg(cl_data->kernel[0], 0, sizeof(cl_mem),   (void*)&in_tex);

  cl_err |= gegl_clSetKernelArg(cl_data->kernel[0], 1, sizeof(cl_mem),   (void*)&out_tex);

  cl_err |= gegl_clSetKernelArg(cl_data->kernel[0], 2, sizeof(cl_float), (void*)&brightness);

  cl_err |= gegl_clSetKernelArg(cl_data->kernel[0], 3, sizeof(cl_float), (void*)&contrast);

  if (cl_err != CL_SUCCESS) return cl_err;

  cl_err = gegl_clEnqueueNDRangeKernel(gegl_cl_get_command_queue (),

                                        cl_data->kernel[0], 1,

                                        NULL, &global_worksize, NULL,

                                        0, NULL, NULL);

  if (cl_err != CL_SUCCESS) return cl_err;

  return cl_err;

}

/*

 * The class init function sets up information needed for this operations class

 * (template) in the GObject OO framework.

 */

static void

gegl_chant_class_init (GeglChantClass *klass)

{

  GeglOperationClass            *operation_class;

  GeglOperationPointFilterClass *point_filter_class;

  operation_class    = GEGL_OPERATION_CLASS (klass);

  point_filter_class = GEGL_OPERATION_POINT_FILTER_CLASS (klass);

  /* override the prepare methods of the GeglOperation class */

  operation_class->prepare = prepare;

  /* override the process method of the point filter class (the process methods

   * of our superclasses deal with the handling on their level of abstraction)

   */

  point_filter_class->process = process;

  point_filter_class->cl_process = cl_process;

  /* specify the name this operation is found under in the GUI/when

   * programming/in XML

   */

  operation_class->opencl_support = TRUE;

  gegl_operation_class_set_keys (operation_class,

      "name",       "gegl:brightness-contrast",

      "categories", "color", 

      "description", _("Changes the light level and contrast."),

      NULL);

}

#endif /* closing #ifdef GEGL_CHANT_PROPERTIES ... else ... */