modules/video_chroma/i420_rgb.c

   1 /*****************************************************************************
   2  * i420_rgb.c : YUV to bitmap RGB conversion module for vlc
   3  *****************************************************************************
   4  * Copyright (C) 2000, 2001, 2004, 2008 VLC authors and VideoLAN
   5  * $Id$
   6  *
   7  * Authors: Sam Hocevar <sam@zoy.org>
   8  *          Damien Fouilleul <damienf@videolan.org>
   9  *
  10  * This program is free software; you can redistribute it and/or modify it
  11  * under the terms of the GNU Lesser General Public License as published by
  12  * the Free Software Foundation; either version 2.1 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  18  * GNU Lesser General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public License
  21  * along with this program; if not, write to the Free Software Foundation,
  22  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  23  *****************************************************************************/
  24
  25 /*****************************************************************************
  26  * Preamble
  27  *****************************************************************************/
  28
  29 #ifdef HAVE_CONFIG_H
  30 # include "config.h"
  31 #endif
  32
  33 #include <math.h>                                            /* exp(), pow() */
  34
  35 #include <vlc_common.h>
  36 #include <vlc_plugin.h>
  37 #include <vlc_filter.h>
  38 #include <vlc_cpu.h>
  39
  40 #include "i420_rgb.h"
  41 #if defined (MODULE_NAME_IS_i420_rgb)
  42 #   include "i420_rgb_c.h"
  43     static picture_t *I420_RGB8_Filter         ( filter_t *, picture_t * );
  44 //    static picture_t *I420_RGB16_dither_Filter ( filter_t *, picture_t * );
  45     static picture_t *I420_RGB16_Filter        ( filter_t *, picture_t * );
  46     static picture_t *I420_RGB32_Filter        ( filter_t *, picture_t * );
  47 #else
  48     static picture_t *I420_R5G5B5_Filter       ( filter_t *, picture_t * );
  49     static picture_t *I420_R5G6B5_Filter       ( filter_t *, picture_t * );
  50     static picture_t *I420_A8R8G8B8_Filter     ( filter_t *, picture_t * );
  51     static picture_t *I420_R8G8B8A8_Filter     ( filter_t *, picture_t * );
  52     static picture_t *I420_B8G8R8A8_Filter     ( filter_t *, picture_t * );
  53     static picture_t *I420_A8B8G8R8_Filter     ( filter_t *, picture_t * );
  54 #endif
  55
  56 /*****************************************************************************
  57  * RGB2PIXEL: assemble RGB components to a pixel value, returns a uint32_t
  58  *****************************************************************************/
  59 #define RGB2PIXEL( p_filter, i_r, i_g, i_b )                 \
  60     (((((uint32_t)i_r) >> p_filter->fmt_out.video.i_rrshift) \
  61                        << p_filter->fmt_out.video.i_lrshift) \
  62    | ((((uint32_t)i_g) >> p_filter->fmt_out.video.i_rgshift) \
  63                        << p_filter->fmt_out.video.i_lgshift) \
  64    | ((((uint32_t)i_b) >> p_filter->fmt_out.video.i_rbshift) \
  65                        << p_filter->fmt_out.video.i_lbshift))
  66
  67 /*****************************************************************************
  68  * Local and extern prototypes.
  69  *****************************************************************************/
  70 static int  Activate   ( vlc_object_t * );
  71 static void Deactivate ( vlc_object_t * );
  72
  73 #if defined (MODULE_NAME_IS_i420_rgb)
  74 static void SetGammaTable       ( int *pi_table, double f_gamma );
  75 static void SetYUV              ( filter_t * );
  76 static void Set8bppPalette      ( filter_t *, uint8_t * );
  77 #endif
  78
  79 /*****************************************************************************
  80  * Module descriptor.
  81  *****************************************************************************/
  82 vlc_module_begin ()
  83 #if defined (MODULE_NAME_IS_i420_rgb)
  84     set_description( N_("I420,IYUV,YV12 to "
  85                        "RGB2,RV15,RV16,RV24,RV32 conversions") )
  86     set_capability( "video filter2", 80 )
  87 # define vlc_CPU_capable() (true)
  88 #elif defined (MODULE_NAME_IS_i420_rgb_mmx)
  89     set_description( N_( "MMX I420,IYUV,YV12 to "
  90                         "RV15,RV16,RV24,RV32 conversions") )
  91     set_capability( "video filter2", 100 )
  92 # define vlc_CPU_capable() vlc_CPU_MMX()
  93 #elif defined (MODULE_NAME_IS_i420_rgb_sse2)
  94     set_description( N_( "SSE2 I420,IYUV,YV12 to "
  95                         "RV15,RV16,RV24,RV32 conversions") )
  96     set_capability( "video filter2", 120 )
  97 # define vlc_CPU_capable() vlc_CPU_SSE2()
  98 #endif
  99     set_callbacks( Activate, Deactivate )
 100 vlc_module_end ()
 101
 102 /*****************************************************************************
 103  * Activate: allocate a chroma function
 104  *****************************************************************************
 105  * This function allocates and initializes a chroma function
 106  *****************************************************************************/
 107 static int Activate( vlc_object_t *p_this )
 108 {
 109     filter_t *p_filter = (filter_t *)p_this;
 110 #if defined (MODULE_NAME_IS_i420_rgb)
 111     size_t i_tables_size;
 112 #endif
 113
 114     if( !vlc_CPU_capable() )
 115         return VLC_EGENERIC;
 116     if( p_filter->fmt_out.video.i_width & 1
 117      || p_filter->fmt_out.video.i_height & 1 )
 118     {
 119         return VLC_EGENERIC;
 120     }
 121
 122     switch( p_filter->fmt_in.video.i_chroma )
 123     {
 124         case VLC_CODEC_YV12:
 125         case VLC_CODEC_I420:
 126             switch( p_filter->fmt_out.video.i_chroma )
 127             {
 128 #if defined (MODULE_NAME_IS_i420_rgb)
 129                 case VLC_CODEC_RGB8:
 130                     p_filter->pf_video_filter = I420_RGB8_Filter;
 131                     break;
 132 #endif
 133                 case VLC_CODEC_RGB15:
 134                 case VLC_CODEC_RGB16:
 135 #if ! defined (MODULE_NAME_IS_i420_rgb)
 136                     /* If we don't have support for the bitmasks, bail out */
 137                     if( ( p_filter->fmt_out.video.i_rmask == 0x7c00
 138                        && p_filter->fmt_out.video.i_gmask == 0x03e0
 139                        && p_filter->fmt_out.video.i_bmask == 0x001f ) )
 140                     {
 141                         /* R5G5B6 pixel format */
 142                         msg_Dbg(p_this, "RGB pixel format is R5G5B5");
 143                         p_filter->pf_video_filter = I420_R5G5B5_Filter;
 144                     }
 145                     else if( ( p_filter->fmt_out.video.i_rmask == 0xf800
 146                             && p_filter->fmt_out.video.i_gmask == 0x07e0
 147                             && p_filter->fmt_out.video.i_bmask == 0x001f ) )
 148                     {
 149                         /* R5G6B5 pixel format */
 150                         msg_Dbg(p_this, "RGB pixel format is R5G6B5");
 151                         p_filter->pf_video_filter = I420_R5G6B5_Filter;
 152                     }
 153                     else
 154                         return VLC_EGENERIC;
 155 #else
 156                     // generic C chroma converter */
 157                     p_filter->pf_video_filter = I420_RGB16_Filter;
 158 #endif
 159                     break;
 160
 161 #if 0
 162                 /* Hmmm, is there only X11 using 32bits per pixel for RV24 ? */
 163                 case VLC_CODEC_RGB24:
 164 #endif
 165
 166                 case VLC_CODEC_RGB32:
 167 #if ! defined (MODULE_NAME_IS_i420_rgb)
 168                     /* If we don't have support for the bitmasks, bail out */
 169                     if( p_filter->fmt_out.video.i_rmask == 0x00ff0000
 170                      && p_filter->fmt_out.video.i_gmask == 0x0000ff00
 171                      && p_filter->fmt_out.video.i_bmask == 0x000000ff )
 172                     {
 173                         /* A8R8G8B8 pixel format */
 174                         msg_Dbg(p_this, "RGB pixel format is A8R8G8B8");
 175                         p_filter->pf_video_filter = I420_A8R8G8B8_Filter;
 176                     }
 177                     else if( p_filter->fmt_out.video.i_rmask == 0xff000000
 178                           && p_filter->fmt_out.video.i_gmask == 0x00ff0000
 179                           && p_filter->fmt_out.video.i_bmask == 0x0000ff00 )
 180                     {
 181                         /* R8G8B8A8 pixel format */
 182                         msg_Dbg(p_this, "RGB pixel format is R8G8B8A8");
 183                         p_filter->pf_video_filter = I420_R8G8B8A8_Filter;
 184                     }
 185                     else if( p_filter->fmt_out.video.i_rmask == 0x0000ff00
 186                           && p_filter->fmt_out.video.i_gmask == 0x00ff0000
 187                           && p_filter->fmt_out.video.i_bmask == 0xff000000 )
 188                     {
 189                         /* B8G8R8A8 pixel format */
 190                         msg_Dbg(p_this, "RGB pixel format is B8G8R8A8");
 191                         p_filter->pf_video_filter = I420_B8G8R8A8_Filter;
 192                     }
 193                     else if( p_filter->fmt_out.video.i_rmask == 0x000000ff
 194                           && p_filter->fmt_out.video.i_gmask == 0x0000ff00
 195                           && p_filter->fmt_out.video.i_bmask == 0x00ff0000 )
 196                     {
 197                         /* A8B8G8R8 pixel format */
 198                         msg_Dbg(p_this, "RGB pixel format is A8B8G8R8");
 199                         p_filter->pf_video_filter = I420_A8B8G8R8_Filter;
 200                     }
 201                     else
 202                         return VLC_EGENERIC;
 203 #else
 204                     /* generic C chroma converter */
 205                     p_filter->pf_video_filter = I420_RGB32_Filter;
 206 #endif
 207                     break;
 208
 209                 default:
 210                     return VLC_EGENERIC;
 211             }
 212             break;
 213
 214         default:
 215             return VLC_EGENERIC;
 216     }
 217
 218     p_filter->p_sys = malloc( sizeof( filter_sys_t ) );
 219     if( p_filter->p_sys == NULL )
 220     {
 221         return VLC_EGENERIC;
 222     }
 223
 224     switch( p_filter->fmt_out.video.i_chroma )
 225     {
 226 #if defined (MODULE_NAME_IS_i420_rgb)
 227         case VLC_CODEC_RGB8:
 228             p_filter->p_sys->p_buffer = malloc( VOUT_MAX_WIDTH );
 229             break;
 230 #endif
 231
 232         case VLC_CODEC_RGB15:
 233         case VLC_CODEC_RGB16:
 234             p_filter->p_sys->p_buffer = malloc( VOUT_MAX_WIDTH * 2 );
 235             break;
 236
 237         case VLC_CODEC_RGB24:
 238         case VLC_CODEC_RGB32:
 239             p_filter->p_sys->p_buffer = malloc( VOUT_MAX_WIDTH * 4 );
 240             break;
 241
 242         default:
 243             p_filter->p_sys->p_buffer = NULL;
 244             break;
 245     }
 246
 247     if( p_filter->p_sys->p_buffer == NULL )
 248     {
 249         free( p_filter->p_sys );
 250         return VLC_EGENERIC;
 251     }
 252
 253     p_filter->p_sys->p_offset = malloc( p_filter->fmt_out.video.i_width
 254                     * ( ( p_filter->fmt_out.video.i_chroma
 255                            == VLC_CODEC_RGB8 ) ? 2 : 1 )
 256                     * sizeof( int ) );
 257     if( p_filter->p_sys->p_offset == NULL )
 258     {
 259         free( p_filter->p_sys->p_buffer );
 260         free( p_filter->p_sys );
 261         return VLC_EGENERIC;
 262     }
 263
 264 #if defined (MODULE_NAME_IS_i420_rgb)
 265     switch( p_filter->fmt_out.video.i_chroma )
 266     {
 267     case VLC_CODEC_RGB8:
 268         i_tables_size = sizeof( uint8_t ) * PALETTE_TABLE_SIZE;
 269         break;
 270     case VLC_CODEC_RGB15:
 271     case VLC_CODEC_RGB16:
 272         i_tables_size = sizeof( uint16_t ) * RGB_TABLE_SIZE;
 273         break;
 274     default: /* RV24, RV32 */
 275         i_tables_size = sizeof( uint32_t ) * RGB_TABLE_SIZE;
 276         break;
 277     }
 278
 279     p_filter->p_sys->p_base = malloc( i_tables_size );
 280     if( p_filter->p_sys->p_base == NULL )
 281     {
 282         free( p_filter->p_sys->p_offset );
 283         free( p_filter->p_sys->p_buffer );
 284         free( p_filter->p_sys );
 285         return -1;
 286     }
 287
 288     SetYUV( p_filter );
 289 #endif
 290
 291     return 0;
 292 }
 293
 294 /*****************************************************************************
 295  * Deactivate: free the chroma function
 296  *****************************************************************************
 297  * This function frees the previously allocated chroma function
 298  *****************************************************************************/
 299 static void Deactivate( vlc_object_t *p_this )
 300 {
 301     filter_t *p_filter = (filter_t *)p_this;
 302
 303 #if defined (MODULE_NAME_IS_i420_rgb)
 304     free( p_filter->p_sys->p_base );
 305 #endif
 306     free( p_filter->p_sys->p_offset );
 307     free( p_filter->p_sys->p_buffer );
 308     free( p_filter->p_sys );
 309 }
 310
 311 #if defined (MODULE_NAME_IS_i420_rgb)
 312 VIDEO_FILTER_WRAPPER( I420_RGB8 )
 313 VIDEO_FILTER_WRAPPER( I420_RGB16 )
 314 //VIDEO_FILTER_WRAPPER( I420_RGB16_dither )
 315 VIDEO_FILTER_WRAPPER( I420_RGB32 )
 316 #else
 317 VIDEO_FILTER_WRAPPER( I420_R5G5B5 )
 318 VIDEO_FILTER_WRAPPER( I420_R5G6B5 )
 319 VIDEO_FILTER_WRAPPER( I420_A8R8G8B8 )
 320 VIDEO_FILTER_WRAPPER( I420_R8G8B8A8 )
 321 VIDEO_FILTER_WRAPPER( I420_B8G8R8A8 )
 322 VIDEO_FILTER_WRAPPER( I420_A8B8G8R8 )
 323 #endif
 324
 325 #if defined (MODULE_NAME_IS_i420_rgb)
 326 /*****************************************************************************
 327  * SetGammaTable: return intensity table transformed by gamma curve.
 328  *****************************************************************************
 329  * pi_table is a table of 256 entries from 0 to 255.
 330  *****************************************************************************/
 331 static void SetGammaTable( int *pi_table, double f_gamma )
 332 {
 333     int i_y;                                               /* base intensity */
 334
 335     /* Use exp(gamma) instead of gamma */
 336     f_gamma = exp( f_gamma );
 337
 338     /* Build gamma table */
 339     for( i_y = 0; i_y < 256; i_y++ )
 340     {
 341         pi_table[ i_y ] = (int)( pow( (double)i_y / 256, f_gamma ) * 256 );
 342     }
 343 }
 344
 345 /*****************************************************************************
 346  * SetYUV: compute tables and set function pointers
 347  *****************************************************************************/
 348 static void SetYUV( filter_t *p_filter )
 349 {
 350     int          pi_gamma[256];                               /* gamma table */
 351     volatile int i_index;                                 /* index in tables */
 352                    /* We use volatile here to work around a strange gcc-3.3.4
 353                     * optimization bug */
 354
 355     /* Build gamma table */
 356     SetGammaTable( pi_gamma, 0 ); //p_filter/*FIXME wasn't used anywhere anyway*/->f_gamma );
 357
 358     /*
 359      * Set pointers and build YUV tables
 360      */
 361
 362     /* Color: build red, green and blue tables */
 363     switch( p_filter->fmt_out.video.i_chroma )
 364     {
 365     case VLC_CODEC_RGB8:
 366         p_filter->p_sys->p_rgb8 = (uint8_t *)p_filter->p_sys->p_base;
 367         Set8bppPalette( p_filter, p_filter->p_sys->p_rgb8 );
 368         break;
 369
 370     case VLC_CODEC_RGB15:
 371     case VLC_CODEC_RGB16:
 372         p_filter->p_sys->p_rgb16 = (uint16_t *)p_filter->p_sys->p_base;
 373         for( i_index = 0; i_index < RED_MARGIN; i_index++ )
 374         {
 375             p_filter->p_sys->p_rgb16[RED_OFFSET - RED_MARGIN + i_index] = RGB2PIXEL( p_filter, pi_gamma[0], 0, 0 );
 376             p_filter->p_sys->p_rgb16[RED_OFFSET + 256 + i_index] =        RGB2PIXEL( p_filter, pi_gamma[255], 0, 0 );
 377         }
 378         for( i_index = 0; i_index < GREEN_MARGIN; i_index++ )
 379         {
 380             p_filter->p_sys->p_rgb16[GREEN_OFFSET - GREEN_MARGIN + i_index] = RGB2PIXEL( p_filter, 0, pi_gamma[0], 0 );
 381             p_filter->p_sys->p_rgb16[GREEN_OFFSET + 256 + i_index] =          RGB2PIXEL( p_filter, 0, pi_gamma[255], 0 );
 382         }
 383         for( i_index = 0; i_index < BLUE_MARGIN; i_index++ )
 384         {
 385             p_filter->p_sys->p_rgb16[BLUE_OFFSET - BLUE_MARGIN + i_index] = RGB2PIXEL( p_filter, 0, 0, pi_gamma[0] );
 386             p_filter->p_sys->p_rgb16[BLUE_OFFSET + BLUE_MARGIN + i_index] = RGB2PIXEL( p_filter, 0, 0, pi_gamma[255] );
 387         }
 388         for( i_index = 0; i_index < 256; i_index++ )
 389         {
 390             p_filter->p_sys->p_rgb16[RED_OFFSET + i_index] =   RGB2PIXEL( p_filter, pi_gamma[ i_index ], 0, 0 );
 391             p_filter->p_sys->p_rgb16[GREEN_OFFSET + i_index] = RGB2PIXEL( p_filter, 0, pi_gamma[ i_index ], 0 );
 392             p_filter->p_sys->p_rgb16[BLUE_OFFSET + i_index] =  RGB2PIXEL( p_filter, 0, 0, pi_gamma[ i_index ] );
 393         }
 394         break;
 395
 396     case VLC_CODEC_RGB24:
 397     case VLC_CODEC_RGB32:
 398         p_filter->p_sys->p_rgb32 = (uint32_t *)p_filter->p_sys->p_base;
 399         for( i_index = 0; i_index < RED_MARGIN; i_index++ )
 400         {
 401             p_filter->p_sys->p_rgb32[RED_OFFSET - RED_MARGIN + i_index] = RGB2PIXEL( p_filter, pi_gamma[0], 0, 0 );
 402             p_filter->p_sys->p_rgb32[RED_OFFSET + 256 + i_index] =        RGB2PIXEL( p_filter, pi_gamma[255], 0, 0 );
 403         }
 404         for( i_index = 0; i_index < GREEN_MARGIN; i_index++ )
 405         {
 406             p_filter->p_sys->p_rgb32[GREEN_OFFSET - GREEN_MARGIN + i_index] = RGB2PIXEL( p_filter, 0, pi_gamma[0], 0 );
 407             p_filter->p_sys->p_rgb32[GREEN_OFFSET + 256 + i_index] =          RGB2PIXEL( p_filter, 0, pi_gamma[255], 0 );
 408         }
 409         for( i_index = 0; i_index < BLUE_MARGIN; i_index++ )
 410         {
 411             p_filter->p_sys->p_rgb32[BLUE_OFFSET - BLUE_MARGIN + i_index] = RGB2PIXEL( p_filter, 0, 0, pi_gamma[0] );
 412             p_filter->p_sys->p_rgb32[BLUE_OFFSET + BLUE_MARGIN + i_index] = RGB2PIXEL( p_filter, 0, 0, pi_gamma[255] );
 413         }
 414         for( i_index = 0; i_index < 256; i_index++ )
 415         {
 416             p_filter->p_sys->p_rgb32[RED_OFFSET + i_index] =   RGB2PIXEL( p_filter, pi_gamma[ i_index ], 0, 0 );
 417             p_filter->p_sys->p_rgb32[GREEN_OFFSET + i_index] = RGB2PIXEL( p_filter, 0, pi_gamma[ i_index ], 0 );
 418             p_filter->p_sys->p_rgb32[BLUE_OFFSET + i_index] =  RGB2PIXEL( p_filter, 0, 0, pi_gamma[ i_index ] );
 419         }
 420         break;
 421     }
 422 }
 423
 424 static void Set8bppPalette( filter_t *p_filter, uint8_t *p_rgb8 )
 425 {
 426     #define CLIP( x ) ( ((x < 0) ? 0 : (x > 255) ? 255 : x) << 8 )
 427
 428     int y,u,v;
 429     int r,g,b;
 430     int i = 0, j = 0;
 431     uint16_t *p_cmap_r = p_filter->p_sys->p_rgb_r;
 432     uint16_t *p_cmap_g = p_filter->p_sys->p_rgb_g;
 433     uint16_t *p_cmap_b = p_filter->p_sys->p_rgb_b;
 434
 435     unsigned char p_lookup[PALETTE_TABLE_SIZE];
 436
 437     /* This loop calculates the intersection of an YUV box and the RGB cube. */
 438     for ( y = 0; y <= 256; y += 16, i += 128 - 81 )
 439     {
 440         for ( u = 0; u <= 256; u += 32 )
 441         {
 442             for ( v = 0; v <= 256; v += 32 )
 443             {
 444                 r = y + ( (V_RED_COEF*(v-128)) >> SHIFT );
 445                 g = y + ( (U_GREEN_COEF*(u-128)
 446                          + V_GREEN_COEF*(v-128)) >> SHIFT );
 447                 b = y + ( (U_BLUE_COEF*(u-128)) >> SHIFT );
 448
 449                 if( r >= 0x00 && g >= 0x00 && b >= 0x00
 450                         && r <= 0xff && g <= 0xff && b <= 0xff )
 451                 {
 452                     /* This one should never happen unless someone
 453                      * fscked up my code */
 454                     if( j == 256 )
 455                     {
 456                         msg_Err( p_filter, "no colors left in palette" );
 457                         break;
 458                     }
 459
 460                     /* Clip the colors */
 461                     p_cmap_r[ j ] = CLIP( r );
 462                     p_cmap_g[ j ] = CLIP( g );
 463                     p_cmap_b[ j ] = CLIP( b );
 464
 465 #if 0
 466             printf("+++Alloc RGB cmap %d (%d, %d, %d)\n", j,
 467                p_cmap_r[ j ] >>8, p_cmap_g[ j ] >>8,
 468                p_cmap_b[ j ] >>8);
 469 #endif
 470
 471                     /* Allocate color */
 472                     p_lookup[ i ] = 1;
 473                     p_rgb8[ i++ ] = j;
 474                     j++;
 475                 }
 476                 else
 477                 {
 478                     p_lookup[ i ] = 0;
 479                     p_rgb8[ i++ ] = 0;
 480                 }
 481             }
 482         }
 483     }
 484
 485     /* The colors have been allocated, we can set the palette */
 486     /* FIXME FIXME FIXME FIXME FIXME FIXME FIXME FIXME FIXME
 487     p_filter->fmt_out.video.pf_setpalette( p_filter, p_cmap_r, p_cmap_g, p_cmap_b );*/
 488
 489 #if 0
 490     /* There will eventually be a way to know which colors
 491      * couldn't be allocated and try to find a replacement */
 492     p_vout->i_white_pixel = 0xff;
 493     p_vout->i_black_pixel = 0x00;
 494     p_vout->i_gray_pixel = 0x44;
 495     p_vout->i_blue_pixel = 0x3b;
 496 #endif
 497
 498     /* This loop allocates colors that got outside the RGB cube */
 499     for ( i = 0, y = 0; y <= 256; y += 16, i += 128 - 81 )
 500     {
 501         for ( u = 0; u <= 256; u += 32 )
 502         {
 503             for ( v = 0; v <= 256; v += 32, i++ )
 504             {
 505                 int u2, v2, dist, mindist = 100000000;
 506
 507                 if( p_lookup[ i ] || y == 0 )
 508                 {
 509                     continue;
 510                 }
 511
 512                 /* Heavy. yeah. */
 513                 for( u2 = 0; u2 <= 256; u2 += 32 )
 514                 {
 515                     for( v2 = 0; v2 <= 256; v2 += 32 )
 516                     {
 517                         j = ((y>>4)<<7) + (u2>>5)*9 + (v2>>5);
 518                         dist = (u-u2)*(u-u2) + (v-v2)*(v-v2);
 519
 520                         /* Find the nearest color */
 521                         if( p_lookup[ j ] && dist < mindist )
 522                         {
 523                             p_rgb8[ i ] = p_rgb8[ j ];
 524                             mindist = dist;
 525                         }
 526
 527                         j -= 128;
 528
 529                         /* Find the nearest color */
 530                         if( p_lookup[ j ] && dist + 128 < mindist )
 531                         {
 532                             p_rgb8[ i ] = p_rgb8[ j ];
 533                             mindist = dist + 128;
 534                         }
 535                     }
 536                 }
 537             }
 538         }
 539     }
 540 }
 541
 542 #endif
 543