/*  RetroArch - A frontend for libretro.
 *  Copyright (C) 2010-2014 - Hans-Kristian Arntzen
 *  Copyright (C) 2011-2014 - Daniel De Matteis
 *
 *  RetroArch 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 Found-
 *  ation, either version 3 of the License, or (at your option) any later version.
 *
 *  RetroArch 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 RetroArch.
 *  If not, see <http://www.gnu.org/licenses/>.
 */

// Compile: gcc -o darken.so -shared darken.c -std=c99 -O3 -Wall -pedantic -fPIC

// Useless filter, just nice as a reference for other filters.

#include "softfilter.h"
#include <stdlib.h>

#ifdef RARCH_INTERNAL
#define softfilter_get_implementation darken_get_implementation
#define softfilter_thread_data darken_softfilter_thread_data
#define filter_data darken_filter_data
#endif

struct softfilter_thread_data
{
   void *out_data;
   const void *in_data;
   size_t out_pitch;
   size_t in_pitch;
   unsigned colfmt;
   unsigned width;
   unsigned height;
   int first;
   int last;
};

struct filter_data
{
   unsigned threads;
   struct softfilter_thread_data *workers;
   unsigned in_fmt;
};

static unsigned darken_input_fmts(void)
{
   return SOFTFILTER_FMT_XRGB8888 | SOFTFILTER_FMT_RGB565;
}

static unsigned darken_output_fmts(unsigned input_fmts)
{
   return input_fmts;
}

static unsigned darken_threads(void *data)
{
   struct filter_data *filt = (struct filter_data*)data;
   return filt->threads;
}

static void *darken_create(unsigned in_fmt, unsigned out_fmt,
      unsigned max_width, unsigned max_height,
      unsigned threads, softfilter_simd_mask_t simd)
{
   (void)simd;

   struct filter_data *filt = (struct filter_data*)calloc(1, sizeof(*filt));
   if (!filt)
      return NULL;
   filt->workers = (struct softfilter_thread_data*)calloc(threads, sizeof(struct softfilter_thread_data));
   filt->threads = threads;
   filt->in_fmt  = in_fmt;
   if (!filt->workers)
   {
      free(filt);
      return NULL;
   }
   return filt;
}

static void darken_output(void *data, unsigned *out_width, unsigned *out_height,
      unsigned width, unsigned height)
{
   *out_width = width;
   *out_height = height;
}

static void darken_destroy(void *data)
{
   struct filter_data *filt = (struct filter_data*)data;
   free(filt->workers);
   free(filt);
}

static void darken_work_cb_xrgb8888(void *data, void *thread_data)
{
   struct softfilter_thread_data *thr = (struct softfilter_thread_data*)thread_data;
   const uint32_t *input = (const uint32_t*)thr->in_data;
   uint32_t *output = (uint32_t*)thr->out_data;
   unsigned width = thr->width;
   unsigned height = thr->height;

   unsigned x, y;
   for (y = 0; y < height; y++, input += thr->in_pitch >> 2, output += thr->out_pitch >> 2)
      for (x = 0; x < width; x++)
         output[x] = (input[x] >> 2) & (0x3f * 0x01010101);
}

static void darken_work_cb_rgb565(void *data, void *thread_data)
{
   struct softfilter_thread_data *thr = (struct softfilter_thread_data*)thread_data;
   const uint16_t *input = (const uint16_t*)thr->in_data;
   uint16_t *output = (uint16_t*)thr->out_data;
   unsigned width = thr->width;
   unsigned height = thr->height;

   unsigned x, y;
   for (y = 0; y < height; y++, input += thr->in_pitch >> 1, output += thr->out_pitch >> 1)
      for (x = 0; x < width; x++)
         output[x] = (input[x] >> 2) & ((0x7 << 0) | (0xf << 5) | (0x7 << 11));
}

static void darken_packets(void *data,
      struct softfilter_work_packet *packets,
      void *output, size_t output_stride,
      const void *input, unsigned width, unsigned height, size_t input_stride)
{
   unsigned i;
   struct filter_data *filt = (struct filter_data*)data;
   for (i = 0; i < filt->threads; i++)
   {
      struct softfilter_thread_data *thr = (struct softfilter_thread_data*)&filt->workers[i];
      unsigned y_start = (height * i) / filt->threads;
      unsigned y_end = (height * (i + 1)) / filt->threads;
      thr->out_data = (uint8_t*)output + y_start * output_stride;
      thr->in_data = (const uint8_t*)input + y_start * input_stride;
      thr->out_pitch = output_stride;
      thr->in_pitch = input_stride;
      thr->width = width;
      thr->height = y_end - y_start;

      if (filt->in_fmt == SOFTFILTER_FMT_XRGB8888)
         packets[i].work = darken_work_cb_xrgb8888;
      else if (filt->in_fmt == SOFTFILTER_FMT_RGB565)
         packets[i].work = darken_work_cb_rgb565;
      packets[i].thread_data = thr;
   }
}

static const struct softfilter_implementation darken = {
   darken_input_fmts,
   darken_output_fmts,

   darken_create,
   darken_destroy,

   darken_threads,
   darken_output,
   darken_packets,
   "Darken",
   SOFTFILTER_API_VERSION,
};

const struct softfilter_implementation *softfilter_get_implementation(softfilter_simd_mask_t simd)
{
   (void)simd;
   return &darken;
}

#ifdef RARCH_INTERNAL
#undef softfilter_get_implementation
#undef softfilter_thread_data
#undef filter_data
#endif