text: /*  RetroArch - A frontend for libretro.
   *  Copyright (C) 2010-2014 - Hans-Kristian Arntzen
   *  Copyright (C) 2011-2018 - 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 upscale_1_5x.so -shared upscale_1_5x.c -std=c99 -O3 -Wall -pedantic -fPIC */
  
  #include "softfilter.h"
  #include <stdlib.h>
  #include <string.h>
  
  #ifdef RARCH_INTERNAL
  #define softfilter_get_implementation upscale_1_5x_get_implementation
  #define softfilter_thread_data upscale_1_5x_softfilter_thread_data
  #define filter_data upscale_1_5x_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 upscale_1_5x_generic_input_fmts(void)
  {
     return SOFTFILTER_FMT_XRGB8888 | SOFTFILTER_FMT_RGB565;
  }
  
  static unsigned upscale_1_5x_generic_output_fmts(unsigned input_fmts)
  {
     return input_fmts;
  }
  
  static unsigned upscale_1_5x_generic_threads(void *data)
  {
     struct filter_data *filt = (struct filter_data*)data;
     return filt->threads;
  }
  
  static void *upscale_1_5x_generic_create(const struct softfilter_config *config,
        unsigned in_fmt, unsigned out_fmt,
        unsigned max_width, unsigned max_height,
        unsigned threads, softfilter_simd_mask_t simd, void *userdata)
  {
     struct filter_data *filt = (struct filter_data*)calloc(1, sizeof(*filt));
     (void)simd;
     (void)config;
     (void)userdata;
  
     if (!filt) {
        return NULL;
     }
     /* Apparently the code is not thread-safe,
      * so force single threaded operation... */
     filt->workers = (struct softfilter_thread_data*)calloc(1, sizeof(struct softfilter_thread_data));
     filt->threads = 1;
     filt->in_fmt  = in_fmt;
     if (!filt->workers) {
        free(filt);
        return NULL;
     }
     return filt;
  }
  
  static void upscale_1_5x_generic_output(void *data,
        unsigned *out_width, unsigned *out_height,
        unsigned width, unsigned height)
  {
     *out_width  = width  + (width  >> 1);
     *out_height = height + (height >> 1);
  }
  
  static void upscale_1_5x_generic_destroy(void *data)
  {
     struct filter_data *filt = (struct filter_data*)data;
     if (!filt) {
        return;
     }
     free(filt->workers);
     free(filt);
  }
  
  static void upscale_1_5x_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;
     uint32_t in_stride                 = (uint32_t)(thr->in_pitch >> 2);
     uint32_t out_stride                = (uint32_t)(thr->out_pitch >> 2);
     uint32_t x, y;
  
     uint32_t color_a;
     uint32_t color_b;
     uint32_t color_c;
     uint32_t color_d;
     uint32_t color_ab;
     uint32_t color_cd;
  
     /* Before:
      *    a b
      *    c d
      *
      * After (parenthesis = average):
      *    a      (a,b)      b
      *    (a,c)  (a,b,c,d)  (b,d)
      *    c      (c,d)      d
      */
  
     for (y = 0; y < thr->height >> 1; y++)
     {
        uint32_t *out_ptr = output;
        for (x = 0; x < thr->width >> 1; x++)
        {
           const uint32_t *in_line_ptr = input + (x << 1);
           uint32_t *out_line_ptr      = out_ptr;
  
           color_a      = *in_line_ptr;
           color_b      = *(in_line_ptr + 1);
           in_line_ptr += in_stride;
  
           color_c      = *in_line_ptr;
           color_d      = *(in_line_ptr + 1);
  
           color_ab     = (color_a + color_b + ((color_a ^ color_b) & 0x1010101)) >> 1;
           color_cd     = (color_c + color_d + ((color_c ^ color_d) & 0x1010101)) >> 1;
  
           /* Row 1 */
           *out_line_ptr       = color_a;
           *(out_line_ptr + 1) = color_ab;
           *(out_line_ptr + 2) = color_b;
           out_line_ptr       += out_stride;
  
           /* Row 2 */
           *out_line_ptr       = (color_a  + color_c  + ((color_a  ^ color_c)  & 0x1010101)) >> 1;
           *(out_line_ptr + 1) = (color_ab + color_cd + ((color_ab ^ color_cd) & 0x1010101)) >> 1;
           *(out_line_ptr + 2) = (color_b  + color_d  + ((color_b  ^ color_d)  & 0x1010101)) >> 1;
           out_line_ptr       += out_stride;
  
           /* Row 3 */
           *out_line_ptr       = color_c;
           *(out_line_ptr + 1) = color_cd;
           *(out_line_ptr + 2) = color_d;
  
           out_ptr += 3;
        }
  
        input  += in_stride << 1;
        output += out_stride * 3;
     }
  }
  
  static void upscale_1_5x_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;
     uint16_t in_stride                 = (uint16_t)(thr->in_pitch >> 1);
     uint16_t out_stride                = (uint16_t)(thr->out_pitch >> 1);
     uint16_t x, y;
  
     uint16_t color_a;
     uint16_t color_b;
     uint16_t color_c;
     uint16_t color_d;
     uint16_t color_ab;
     uint16_t color_cd;
  
     /* Before:
      *    a b
      *    c d
      *
      * After (parenthesis = average):
      *    a      (a,b)      b
      *    (a,c)  (a,b,c,d)  (b,d)
      *    c      (c,d)      d
      */
  
     for (y = 0; y < thr->height >> 1; y++)
     {
        uint16_t *out_ptr = output;
        for (x = 0; x < thr->width >> 1; x++)
        {
           const uint16_t *in_line_ptr = input + (x << 1);
           uint16_t *out_line_ptr      = out_ptr;
  
           color_a      = *in_line_ptr;
           color_b      = *(in_line_ptr + 1);
           in_line_ptr += in_stride;
  
           color_c      = *in_line_ptr;
           color_d      = *(in_line_ptr + 1);
  
           color_ab     = (color_a + color_b + ((color_a ^ color_b) & 0x821)) >> 1;
           color_cd     = (color_c + color_d + ((color_c ^ color_d) & 0x821)) >> 1;
  
           /* Row 1 */
           *out_line_ptr       = color_a;
           *(out_line_ptr + 1) = color_ab;
           *(out_line_ptr + 2) = color_b;
           out_line_ptr       += out_stride;
  
           /* Row 2 */
           *out_line_ptr       = (color_a  + color_c  + ((color_a  ^ color_c)  & 0x821)) >> 1;
           *(out_line_ptr + 1) = (color_ab + color_cd + ((color_ab ^ color_cd) & 0x821)) >> 1;
           *(out_line_ptr + 2) = (color_b  + color_d  + ((color_b  ^ color_d)  & 0x821)) >> 1;
           out_line_ptr       += out_stride;
  
           /* Row 3 */
           *out_line_ptr       = color_c;
           *(out_line_ptr + 1) = color_cd;
           *(out_line_ptr + 2) = color_d;
  
           out_ptr += 3;
        }
  
        input  += in_stride << 1;
        output += out_stride * 3;
     }
  }
  
  static void upscale_1_5x_generic_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)
  {
     /* We are guaranteed single threaded operation
      * (filt->threads = 1) so we don't need to loop
      * over threads and can cull some code. This only
      * makes the tiniest performance difference, but
      * every little helps when running on an o3DS... */
     struct filter_data *filt = (struct filter_data*)data;
     struct softfilter_thread_data *thr = (struct softfilter_thread_data*)&filt->workers[0];
  
     thr->out_data = (uint8_t*)output;
     thr->in_data = (const uint8_t*)input;
     thr->out_pitch = output_stride;
     thr->in_pitch = input_stride;
     thr->width = width;
     thr->height = height;
  
     if (filt->in_fmt == SOFTFILTER_FMT_XRGB8888) {
        packets[0].work = upscale_1_5x_work_cb_xrgb8888;
     } else if (filt->in_fmt == SOFTFILTER_FMT_RGB565) {
        packets[0].work = upscale_1_5x_work_cb_rgb565;
     }
     packets[0].thread_data = thr;
  }
  
  static const struct softfilter_implementation upscale_1_5x_generic = {
     upscale_1_5x_generic_input_fmts,
     upscale_1_5x_generic_output_fmts,
  
     upscale_1_5x_generic_create,
     upscale_1_5x_generic_destroy,
  
     upscale_1_5x_generic_threads,
     upscale_1_5x_generic_output,
     upscale_1_5x_generic_packets,
  
     SOFTFILTER_API_VERSION,
     "Upscale1.5x",
     "upscale_1_5x",
  };
  
  const struct softfilter_implementation *softfilter_get_implementation(
        softfilter_simd_mask_t simd)
  {
     (void)simd;
     return &upscale_1_5x_generic;
  }
  
  #ifdef RARCH_INTERNAL
  #undef softfilter_get_implementation
  #undef softfilter_thread_data
  #undef filter_data
  #endif
  