1 /* 2 SDL - Simple DirectMedia Layer 3 Copyright (C) 1997-2006 Sam Lantinga 4 5 This library is free software; you can redistribute it and/or 6 modify it under the terms of the GNU Lesser General Public 7 License as published by the Free Software Foundation; either 8 version 2.1 of the License, or (at your option) any later version. 9 10 This library is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13 Lesser General Public License for more details. 14 15 You should have received a copy of the GNU Lesser General Public 16 License along with this library; if not, write to the Free Software 17 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 18 19 Sam Lantinga 20 slouken (at) libsdl.org 21 */ 22 #include "SDL_config.h" 23 24 /* General (mostly internal) pixel/color manipulation routines for SDL */ 25 26 #include "SDL_endian.h" 27 #include "SDL_video.h" 28 #include "SDL_sysvideo.h" 29 #include "SDL_blit.h" 30 #include "SDL_pixels_c.h" 31 #include "SDL_RLEaccel_c.h" 32 33 /* Helper functions */ 34 /* 35 * Allocate a pixel format structure and fill it according to the given info. 36 */ 37 SDL_PixelFormat *SDL_AllocFormat(int bpp, 38 Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask) 39 { 40 SDL_PixelFormat *format; 41 Uint32 mask; 42 43 /* Allocate an empty pixel format structure */ 44 format = SDL_malloc(sizeof(*format)); 45 if ( format == NULL ) { 46 SDL_OutOfMemory(); 47 return(NULL); 48 } 49 SDL_memset(format, 0, sizeof(*format)); 50 format->alpha = SDL_ALPHA_OPAQUE; 51 52 /* Set up the format */ 53 format->BitsPerPixel = bpp; 54 format->BytesPerPixel = (bpp+7)/8; 55 if ( Rmask || Bmask || Gmask ) { /* Packed pixels with custom mask */ 56 format->palette = NULL; 57 format->Rshift = 0; 58 format->Rloss = 8; 59 if ( Rmask ) { 60 for ( mask = Rmask; !(mask&0x01); mask >>= 1 ) 61 ++format->Rshift; 62 for ( ; (mask&0x01); mask >>= 1 ) 63 --format->Rloss; 64 } 65 format->Gshift = 0; 66 format->Gloss = 8; 67 if ( Gmask ) { 68 for ( mask = Gmask; !(mask&0x01); mask >>= 1 ) 69 ++format->Gshift; 70 for ( ; (mask&0x01); mask >>= 1 ) 71 --format->Gloss; 72 } 73 format->Bshift = 0; 74 format->Bloss = 8; 75 if ( Bmask ) { 76 for ( mask = Bmask; !(mask&0x01); mask >>= 1 ) 77 ++format->Bshift; 78 for ( ; (mask&0x01); mask >>= 1 ) 79 --format->Bloss; 80 } 81 format->Ashift = 0; 82 format->Aloss = 8; 83 if ( Amask ) { 84 for ( mask = Amask; !(mask&0x01); mask >>= 1 ) 85 ++format->Ashift; 86 for ( ; (mask&0x01); mask >>= 1 ) 87 --format->Aloss; 88 } 89 format->Rmask = Rmask; 90 format->Gmask = Gmask; 91 format->Bmask = Bmask; 92 format->Amask = Amask; 93 } else if ( bpp > 8 ) { /* Packed pixels with standard mask */ 94 /* R-G-B */ 95 if ( bpp > 24 ) 96 bpp = 24; 97 format->Rloss = 8-(bpp/3); 98 format->Gloss = 8-(bpp/3)-(bpp%3); 99 format->Bloss = 8-(bpp/3); 100 format->Rshift = ((bpp/3)+(bpp%3))+(bpp/3); 101 format->Gshift = (bpp/3); 102 format->Bshift = 0; 103 format->Rmask = ((0xFF>>format->Rloss)<<format->Rshift); 104 format->Gmask = ((0xFF>>format->Gloss)<<format->Gshift); 105 format->Bmask = ((0xFF>>format->Bloss)<<format->Bshift); 106 } else { 107 /* Palettized formats have no mask info */ 108 format->Rloss = 8; 109 format->Gloss = 8; 110 format->Bloss = 8; 111 format->Aloss = 8; 112 format->Rshift = 0; 113 format->Gshift = 0; 114 format->Bshift = 0; 115 format->Ashift = 0; 116 format->Rmask = 0; 117 format->Gmask = 0; 118 format->Bmask = 0; 119 format->Amask = 0; 120 } 121 if ( bpp <= 8 ) { /* Palettized mode */ 122 int ncolors = 1<<bpp; 123 #ifdef DEBUG_PALETTE 124 fprintf(stderr,"bpp=%d ncolors=%d\n",bpp,ncolors); 125 #endif 126 format->palette = (SDL_Palette *)SDL_malloc(sizeof(SDL_Palette)); 127 if ( format->palette == NULL ) { 128 SDL_FreeFormat(format); 129 SDL_OutOfMemory(); 130 return(NULL); 131 } 132 (format->palette)->ncolors = ncolors; 133 (format->palette)->colors = (SDL_Color *)SDL_malloc( 134 (format->palette)->ncolors*sizeof(SDL_Color)); 135 if ( (format->palette)->colors == NULL ) { 136 SDL_FreeFormat(format); 137 SDL_OutOfMemory(); 138 return(NULL); 139 } 140 if ( Rmask || Bmask || Gmask ) { 141 /* create palette according to masks */ 142 int i; 143 int Rm=0,Gm=0,Bm=0; 144 int Rw=0,Gw=0,Bw=0; 145 #ifdef ENABLE_PALETTE_ALPHA 146 int Am=0,Aw=0; 147 #endif 148 if(Rmask) 149 { 150 Rw=8-format->Rloss; 151 for(i=format->Rloss;i>0;i-=Rw) 152 Rm|=1<<i; 153 } 154 #ifdef DEBUG_PALETTE 155 fprintf(stderr,"Rw=%d Rm=0x%02X\n",Rw,Rm); 156 #endif 157 if(Gmask) 158 { 159 Gw=8-format->Gloss; 160 for(i=format->Gloss;i>0;i-=Gw) 161 Gm|=1<<i; 162 } 163 #ifdef DEBUG_PALETTE 164 fprintf(stderr,"Gw=%d Gm=0x%02X\n",Gw,Gm); 165 #endif 166 if(Bmask) 167 { 168 Bw=8-format->Bloss; 169 for(i=format->Bloss;i>0;i-=Bw) 170 Bm|=1<<i; 171 } 172 #ifdef DEBUG_PALETTE 173 fprintf(stderr,"Bw=%d Bm=0x%02X\n",Bw,Bm); 174 #endif 175 #ifdef ENABLE_PALETTE_ALPHA 176 if(Amask) 177 { 178 Aw=8-format->Aloss; 179 for(i=format->Aloss;i>0;i-=Aw) 180 Am|=1<<i; 181 } 182 # ifdef DEBUG_PALETTE 183 fprintf(stderr,"Aw=%d Am=0x%02X\n",Aw,Am); 184 # endif 185 #endif 186 for(i=0; i < ncolors; ++i) { 187 int r,g,b; 188 r=(i&Rmask)>>format->Rshift; 189 r=(r<<format->Rloss)|((r*Rm)>>Rw); 190 format->palette->colors[i].r=r; 191 192 g=(i&Gmask)>>format->Gshift; 193 g=(g<<format->Gloss)|((g*Gm)>>Gw); 194 format->palette->colors[i].g=g; 195 196 b=(i&Bmask)>>format->Bshift; 197 b=(b<<format->Bloss)|((b*Bm)>>Bw); 198 format->palette->colors[i].b=b; 199 200 #ifdef ENABLE_PALETTE_ALPHA 201 a=(i&Amask)>>format->Ashift; 202 a=(a<<format->Aloss)|((a*Am)>>Aw); 203 format->palette->colors[i].unused=a; 204 #else 205 format->palette->colors[i].unused=0; 206 #endif 207 } 208 } else if ( ncolors == 2 ) { 209 /* Create a black and white bitmap palette */ 210 format->palette->colors[0].r = 0xFF; 211 format->palette->colors[0].g = 0xFF; 212 format->palette->colors[0].b = 0xFF; 213 format->palette->colors[1].r = 0x00; 214 format->palette->colors[1].g = 0x00; 215 format->palette->colors[1].b = 0x00; 216 } else { 217 /* Create an empty palette */ 218 SDL_memset((format->palette)->colors, 0, 219 (format->palette)->ncolors*sizeof(SDL_Color)); 220 } 221 } 222 return(format); 223 } 224 SDL_PixelFormat *SDL_ReallocFormat(SDL_Surface *surface, int bpp, 225 Uint32 Rmask, Uint32 Gmask, Uint32 Bmask, Uint32 Amask) 226 { 227 if ( surface->format ) { 228 SDL_FreeFormat(surface->format); 229 SDL_FormatChanged(surface); 230 } 231 surface->format = SDL_AllocFormat(bpp, Rmask, Gmask, Bmask, Amask); 232 return surface->format; 233 } 234 235 /* 236 * Change any previous mappings from/to the new surface format 237 */ 238 void SDL_FormatChanged(SDL_Surface *surface) 239 { 240 static int format_version = 0; 241 ++format_version; 242 if ( format_version < 0 ) { /* It wrapped... */ 243 format_version = 1; 244 } 245 surface->format_version = format_version; 246 SDL_InvalidateMap(surface->map); 247 } 248 /* 249 * Free a previously allocated format structure 250 */ 251 void SDL_FreeFormat(SDL_PixelFormat *format) 252 { 253 if ( format ) { 254 if ( format->palette ) { 255 if ( format->palette->colors ) { 256 SDL_free(format->palette->colors); 257 } 258 SDL_free(format->palette); 259 } 260 SDL_free(format); 261 } 262 } 263 /* 264 * Calculate an 8-bit (3 red, 3 green, 2 blue) dithered palette of colors 265 */ 266 void SDL_DitherColors(SDL_Color *colors, int bpp) 267 { 268 int i; 269 if(bpp != 8) 270 return; /* only 8bpp supported right now */ 271 272 for(i = 0; i < 256; i++) { 273 int r, g, b; 274 /* map each bit field to the full [0, 255] interval, 275 so 0 is mapped to (0, 0, 0) and 255 to (255, 255, 255) */ 276 r = i & 0xe0; 277 r |= r >> 3 | r >> 6; 278 colors[i].r = r; 279 g = (i << 3) & 0xe0; 280 g |= g >> 3 | g >> 6; 281 colors[i].g = g; 282 b = i & 0x3; 283 b |= b << 2; 284 b |= b << 4; 285 colors[i].b = b; 286 } 287 } 288 /* 289 * Calculate the pad-aligned scanline width of a surface 290 */ 291 Uint16 SDL_CalculatePitch(SDL_Surface *surface) 292 { 293 Uint16 pitch; 294 295 /* Surface should be 4-byte aligned for speed */ 296 pitch = surface->w*surface->format->BytesPerPixel; 297 switch (surface->format->BitsPerPixel) { 298 case 1: 299 pitch = (pitch+7)/8; 300 break; 301 case 4: 302 pitch = (pitch+1)/2; 303 break; 304 default: 305 break; 306 } 307 pitch = (pitch + 3) & ~3; /* 4-byte aligning */ 308 return(pitch); 309 } 310 /* 311 * Match an RGB value to a particular palette index 312 */ 313 Uint8 SDL_FindColor(SDL_Palette *pal, Uint8 r, Uint8 g, Uint8 b) 314 { 315 /* Do colorspace distance matching */ 316 unsigned int smallest; 317 unsigned int distance; 318 int rd, gd, bd; 319 int i; 320 Uint8 pixel=0; 321 322 smallest = ~0; 323 for ( i=0; i<pal->ncolors; ++i ) { 324 rd = pal->colors[i].r - r; 325 gd = pal->colors[i].g - g; 326 bd = pal->colors[i].b - b; 327 distance = (rd*rd)+(gd*gd)+(bd*bd); 328 if ( distance < smallest ) { 329 pixel = i; 330 if ( distance == 0 ) { /* Perfect match! */ 331 break; 332 } 333 smallest = distance; 334 } 335 } 336 return(pixel); 337 } 338 339 /* Find the opaque pixel value corresponding to an RGB triple */ 340 Uint32 SDL_MapRGB 341 (const SDL_PixelFormat * const format, 342 const Uint8 r, const Uint8 g, const Uint8 b) 343 { 344 if ( format->palette == NULL ) { 345 return (r >> format->Rloss) << format->Rshift 346 | (g >> format->Gloss) << format->Gshift 347 | (b >> format->Bloss) << format->Bshift 348 | format->Amask; 349 } else { 350 return SDL_FindColor(format->palette, r, g, b); 351 } 352 } 353 354 /* Find the pixel value corresponding to an RGBA quadruple */ 355 Uint32 SDL_MapRGBA 356 (const SDL_PixelFormat * const format, 357 const Uint8 r, const Uint8 g, const Uint8 b, const Uint8 a) 358 { 359 if ( format->palette == NULL ) { 360 return (r >> format->Rloss) << format->Rshift 361 | (g >> format->Gloss) << format->Gshift 362 | (b >> format->Bloss) << format->Bshift 363 | ((a >> format->Aloss) << format->Ashift & format->Amask); 364 } else { 365 return SDL_FindColor(format->palette, r, g, b); 366 } 367 } 368 369 void SDL_GetRGBA(Uint32 pixel, SDL_PixelFormat *fmt, 370 Uint8 *r, Uint8 *g, Uint8 *b, Uint8 *a) 371 { 372 if ( fmt->palette == NULL ) { 373 /* 374 * This makes sure that the result is mapped to the 375 * interval [0..255], and the maximum value for each 376 * component is 255. This is important to make sure 377 * that white is indeed reported as (255, 255, 255), 378 * and that opaque alpha is 255. 379 * This only works for RGB bit fields at least 4 bit 380 * wide, which is almost always the case. 381 */ 382 unsigned v; 383 v = (pixel & fmt->Rmask) >> fmt->Rshift; 384 *r = (v << fmt->Rloss) + (v >> (8 - (fmt->Rloss << 1))); 385 v = (pixel & fmt->Gmask) >> fmt->Gshift; 386 *g = (v << fmt->Gloss) + (v >> (8 - (fmt->Gloss << 1))); 387 v = (pixel & fmt->Bmask) >> fmt->Bshift; 388 *b = (v << fmt->Bloss) + (v >> (8 - (fmt->Bloss << 1))); 389 if(fmt->Amask) { 390 v = (pixel & fmt->Amask) >> fmt->Ashift; 391 *a = (v << fmt->Aloss) + (v >> (8 - (fmt->Aloss << 1))); 392 } else { 393 *a = SDL_ALPHA_OPAQUE; 394 } 395 } else { 396 *r = fmt->palette->colors[pixel].r; 397 *g = fmt->palette->colors[pixel].g; 398 *b = fmt->palette->colors[pixel].b; 399 *a = SDL_ALPHA_OPAQUE; 400 } 401 } 402 403 void SDL_GetRGB(Uint32 pixel, SDL_PixelFormat *fmt, Uint8 *r,Uint8 *g,Uint8 *b) 404 { 405 if ( fmt->palette == NULL ) { 406 /* the note for SDL_GetRGBA above applies here too */ 407 unsigned v; 408 v = (pixel & fmt->Rmask) >> fmt->Rshift; 409 *r = (v << fmt->Rloss) + (v >> (8 - (fmt->Rloss << 1))); 410 v = (pixel & fmt->Gmask) >> fmt->Gshift; 411 *g = (v << fmt->Gloss) + (v >> (8 - (fmt->Gloss << 1))); 412 v = (pixel & fmt->Bmask) >> fmt->Bshift; 413 *b = (v << fmt->Bloss) + (v >> (8 - (fmt->Bloss << 1))); 414 } else { 415 *r = fmt->palette->colors[pixel].r; 416 *g = fmt->palette->colors[pixel].g; 417 *b = fmt->palette->colors[pixel].b; 418 } 419 } 420 421 /* Apply gamma to a set of colors - this is easy. :) */ 422 void SDL_ApplyGamma(Uint16 *gamma, SDL_Color *colors, SDL_Color *output, 423 int ncolors) 424 { 425 int i; 426 427 for ( i=0; i<ncolors; ++i ) { 428 output[i].r = gamma[0*256 + colors[i].r] >> 8; 429 output[i].g = gamma[1*256 + colors[i].g] >> 8; 430 output[i].b = gamma[2*256 + colors[i].b] >> 8; 431 } 432 } 433 434 /* Map from Palette to Palette */ 435 static Uint8 *Map1to1(SDL_Palette *src, SDL_Palette *dst, int *identical) 436 { 437 Uint8 *map; 438 int i; 439 440 if ( identical ) { 441 if ( src->ncolors <= dst->ncolors ) { 442 /* If an identical palette, no need to map */ 443 if ( SDL_memcmp(src->colors, dst->colors, src->ncolors* 444 sizeof(SDL_Color)) == 0 ) { 445 *identical = 1; 446 return(NULL); 447 } 448 } 449 *identical = 0; 450 } 451 map = (Uint8 *)SDL_malloc(src->ncolors); 452 if ( map == NULL ) { 453 SDL_OutOfMemory(); 454 return(NULL); 455 } 456 for ( i=0; i<src->ncolors; ++i ) { 457 map[i] = SDL_FindColor(dst, 458 src->colors[i].r, src->colors[i].g, src->colors[i].b); 459 } 460 return(map); 461 } 462 /* Map from Palette to BitField */ 463 static Uint8 *Map1toN(SDL_PixelFormat *src, SDL_PixelFormat *dst) 464 { 465 Uint8 *map; 466 int i; 467 int bpp; 468 unsigned alpha; 469 SDL_Palette *pal = src->palette; 470 471 bpp = ((dst->BytesPerPixel == 3) ? 4 : dst->BytesPerPixel); 472 map = (Uint8 *)SDL_malloc(pal->ncolors*bpp); 473 if ( map == NULL ) { 474 SDL_OutOfMemory(); 475 return(NULL); 476 } 477 478 alpha = dst->Amask ? src->alpha : 0; 479 /* We memory copy to the pixel map so the endianness is preserved */ 480 for ( i=0; i<pal->ncolors; ++i ) { 481 ASSEMBLE_RGBA(&map[i*bpp], dst->BytesPerPixel, dst, 482 pal->colors[i].r, pal->colors[i].g, 483 pal->colors[i].b, alpha); 484 } 485 return(map); 486 } 487 /* Map from BitField to Dithered-Palette to Palette */ 488 static Uint8 *MapNto1(SDL_PixelFormat *src, SDL_PixelFormat *dst, int *identical) 489 { 490 /* Generate a 256 color dither palette */ 491 SDL_Palette dithered; 492 SDL_Color colors[256]; 493 SDL_Palette *pal = dst->palette; 494 495 /* SDL_DitherColors does not initialize the 'unused' component of colors, 496 but Map1to1 compares it against pal, so we should initialize it. */ 497 SDL_memset(colors, 0, sizeof(colors)); 498 499 dithered.ncolors = 256; 500 SDL_DitherColors(colors, 8); 501 dithered.colors = colors; 502 return(Map1to1(&dithered, pal, identical)); 503 } 504 505 SDL_BlitMap *SDL_AllocBlitMap(void) 506 { 507 SDL_BlitMap *map; 508 509 /* Allocate the empty map */ 510 map = (SDL_BlitMap *)SDL_malloc(sizeof(*map)); 511 if ( map == NULL ) { 512 SDL_OutOfMemory(); 513 return(NULL); 514 } 515 SDL_memset(map, 0, sizeof(*map)); 516 517 /* Allocate the software blit data */ 518 map->sw_data = (struct private_swaccel *)SDL_malloc(sizeof(*map->sw_data)); 519 if ( map->sw_data == NULL ) { 520 SDL_FreeBlitMap(map); 521 SDL_OutOfMemory(); 522 return(NULL); 523 } 524 SDL_memset(map->sw_data, 0, sizeof(*map->sw_data)); 525 526 /* It's ready to go */ 527 return(map); 528 } 529 void SDL_InvalidateMap(SDL_BlitMap *map) 530 { 531 if ( ! map ) { 532 return; 533 } 534 map->dst = NULL; 535 map->format_version = (unsigned int)-1; 536 if ( map->table ) { 537 SDL_free(map->table); 538 map->table = NULL; 539 } 540 } 541 int SDL_MapSurface (SDL_Surface *src, SDL_Surface *dst) 542 { 543 SDL_PixelFormat *srcfmt; 544 SDL_PixelFormat *dstfmt; 545 SDL_BlitMap *map; 546 547 /* Clear out any previous mapping */ 548 map = src->map; 549 if ( (src->flags & SDL_RLEACCEL) == SDL_RLEACCEL ) { 550 SDL_UnRLESurface(src, 1); 551 } 552 SDL_InvalidateMap(map); 553 554 /* Figure out what kind of mapping we're doing */ 555 map->identity = 0; 556 srcfmt = src->format; 557 dstfmt = dst->format; 558 switch (srcfmt->BytesPerPixel) { 559 case 1: 560 switch (dstfmt->BytesPerPixel) { 561 case 1: 562 /* Palette --> Palette */ 563 /* If both SDL_HWSURFACE, assume have same palette */ 564 if ( ((src->flags & SDL_HWSURFACE) == SDL_HWSURFACE) && 565 ((dst->flags & SDL_HWSURFACE) == SDL_HWSURFACE) ) { 566 map->identity = 1; 567 } else { 568 map->table = Map1to1(srcfmt->palette, 569 dstfmt->palette, &map->identity); 570 } 571 if ( ! map->identity ) { 572 if ( map->table == NULL ) { 573 return(-1); 574 } 575 } 576 if (srcfmt->BitsPerPixel!=dstfmt->BitsPerPixel) 577 map->identity = 0; 578 break; 579 580 default: 581 /* Palette --> BitField */ 582 map->table = Map1toN(srcfmt, dstfmt); 583 if ( map->table == NULL ) { 584 return(-1); 585 } 586 break; 587 } 588 break; 589 default: 590 switch (dstfmt->BytesPerPixel) { 591 case 1: 592 /* BitField --> Palette */ 593 map->table = MapNto1(srcfmt, dstfmt, &map->identity); 594 if ( ! map->identity ) { 595 if ( map->table == NULL ) { 596 return(-1); 597 } 598 } 599 map->identity = 0; /* Don't optimize to copy */ 600 break; 601 default: 602 /* BitField --> BitField */ 603 if ( FORMAT_EQUAL(srcfmt, dstfmt) ) 604 map->identity = 1; 605 break; 606 } 607 break; 608 } 609 610 map->dst = dst; 611 map->format_version = dst->format_version; 612 613 /* Choose your blitters wisely */ 614 return(SDL_CalculateBlit(src)); 615 } 616 void SDL_FreeBlitMap(SDL_BlitMap *map) 617 { 618 if ( map ) { 619 SDL_InvalidateMap(map); 620 if ( map->sw_data != NULL ) { 621 SDL_free(map->sw_data); 622 } 623 SDL_free(map); 624 } 625 } 626
