text: /* sms_ntsc 0.2.3. http://www.slack.net/~ant/ */
  
  /* Modified for use with Genesis Plus GX -- EkeEke */
  
  #include "shared.h"
  #include "sms_ntsc.h"
  
  /* Copyright (C) 2006-2007 Shay Green. This module 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 2.1 of the License, or (at your option) any later version. This
  module 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 this module; if not, write to the Free Software Foundation,
  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */
  
  sms_ntsc_setup_t const sms_ntsc_monochrome = { 0,-1, 0, 0,.2,  0, .2,-.2,-.2,-1, 0,  0 };
  sms_ntsc_setup_t const sms_ntsc_composite  = { 0, 0, 0, 0, 0,  0,.25,  0,  0, 0, 0,  0 };
  sms_ntsc_setup_t const sms_ntsc_svideo     = { 0, 0, 0, 0, 0,  0,.25, -1, -1, 0, 0,  0 };
  sms_ntsc_setup_t const sms_ntsc_rgb        = { 0, 0, 0, 0,.2,  0,.70, -1, -1,-1, 0,  0 };
  
  #define alignment_count 3
  #define burst_count     1
  #define rescale_in      8
  #define rescale_out     7
  
  #define artifacts_mid   0.4f
  #define artifacts_max   1.2f
  #define fringing_mid    0.8f
  #define std_decoder_hue 0
  
  #define gamma_size      16
  
  #include "sms_ntsc_impl.h"
  
  /* 3 input pixels -> 8 composite samples */
  pixel_info_t const sms_ntsc_pixels [alignment_count] = {
    { PIXEL_OFFSET( -4, -9 ), { 1, 1, .6667f, 0 } },
    { PIXEL_OFFSET( -2, -7 ), {       .3333f, 1, 1, .3333f } },
    { PIXEL_OFFSET(  0, -5 ), {                  0, .6667f, 1, 1 } },
  };
  
  static void correct_errors( sms_ntsc_rgb_t color, sms_ntsc_rgb_t* out )
  {
    unsigned i;
    for ( i = 0; i < rgb_kernel_size / 2; i++ )
    {
      sms_ntsc_rgb_t error = color -
          out [i    ] - out [(i+12)%14+14] - out [(i+10)%14+28] -
          out [i + 7] - out [i + 5    +14] - out [i + 3    +28];
      CORRECT_ERROR( i + 3 + 28 );
    }
  }
  
  void sms_ntsc_init( sms_ntsc_t* ntsc, sms_ntsc_setup_t const* setup )
  {
    int entry;
    init_t impl;
    if ( !setup )
      setup = &sms_ntsc_composite;
    init( &impl, setup );
    
    for ( entry = 0; entry < sms_ntsc_palette_size; entry++ )
    {
      float bb = impl.to_float [entry >> 8 & 0x0F];
      float gg = impl.to_float [entry >> 4 & 0x0F];
      float rr = impl.to_float [entry      & 0x0F];
      
      float y, i, q = RGB_TO_YIQ( rr, gg, bb, y, i );
      
      int r, g, b = YIQ_TO_RGB( y, i, q, impl.to_rgb, int, r, g );
      sms_ntsc_rgb_t rgb = PACK_RGB( r, g, b );
      
      if ( setup->palette_out )
        RGB_PALETTE_OUT( rgb, &setup->palette_out [entry * 3] );
      
      if ( ntsc )
      {
        gen_kernel( &impl, y, i, q, ntsc->table [entry] );
        correct_errors( rgb, ntsc->table [entry] );
      }
    }
  }
  
  #ifndef CUSTOM_BLITTER
  void sms_ntsc_blit( sms_ntsc_t const* ntsc, SMS_NTSC_IN_T const* table, unsigned char* input,
                      int in_width, int vline)
  {
    int const chunk_count = in_width / sms_ntsc_in_chunk;
  
    /* handle extra 0, 1, or 2 pixels by placing them at beginning of row */
    int const in_extra = in_width - chunk_count * sms_ntsc_in_chunk;
    unsigned const extra2 = (unsigned) -(in_extra >> 1 & 1); /* (unsigned) -1 = ~0 */
    unsigned const extra1 = (unsigned) -(in_extra & 1) | extra2;
  
    /* use palette entry 0 for unused pixels */
    SMS_NTSC_IN_T border = table[0];
  
    SMS_NTSC_BEGIN_ROW( ntsc, border,
        (SMS_NTSC_ADJ_IN( table[input[0]] )) & extra2,
        (SMS_NTSC_ADJ_IN( table[input[extra2 & 1]] )) & extra1 );
  
    sms_ntsc_out_t* restrict line_out  = (sms_ntsc_out_t*)(&bitmap.data[(vline * bitmap.pitch)]);
  
    int n;
    input += in_extra;
  
    for ( n = chunk_count; n; --n )
    {
      /* order of input and output pixels must not be altered */
      SMS_NTSC_COLOR_IN( 0, ntsc, SMS_NTSC_ADJ_IN( table[*input++] ) );
      SMS_NTSC_RGB_OUT( 0, *line_out++ );
      SMS_NTSC_RGB_OUT( 1, *line_out++ );
      
      SMS_NTSC_COLOR_IN( 1, ntsc, SMS_NTSC_ADJ_IN( table[*input++] ) );
      SMS_NTSC_RGB_OUT( 2, *line_out++ );
      SMS_NTSC_RGB_OUT( 3, *line_out++ );
        
      SMS_NTSC_COLOR_IN( 2, ntsc, SMS_NTSC_ADJ_IN( table[*input++] ) );
      SMS_NTSC_RGB_OUT( 4, *line_out++ );
      SMS_NTSC_RGB_OUT( 5, *line_out++ );
      SMS_NTSC_RGB_OUT( 6, *line_out++ );
    }
  
    /* finish final pixels */
    SMS_NTSC_COLOR_IN( 0, ntsc, border );
    SMS_NTSC_RGB_OUT( 0, *line_out++ );
    SMS_NTSC_RGB_OUT( 1, *line_out++ );
  
    SMS_NTSC_COLOR_IN( 1, ntsc, border );
    SMS_NTSC_RGB_OUT( 2, *line_out++ );
    SMS_NTSC_RGB_OUT( 3, *line_out++ );
  
    SMS_NTSC_COLOR_IN( 2, ntsc, border );
    SMS_NTSC_RGB_OUT( 4, *line_out++ );
    SMS_NTSC_RGB_OUT( 5, *line_out++ );
    SMS_NTSC_RGB_OUT( 6, *line_out++ );
  }
  #endif
  