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annotate docs/html/guidevideoexamples.html @ 220:7861d904fb77
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| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Thu, 01 Nov 2001 16:45:40 +0000 |
| parents | 55f1f1b3e27d |
| children |
| rev | line source |
|---|---|
| 0 | 1 <HTML |
| 2 ><HEAD | |
| 3 ><TITLE | |
| 4 >Video Examples</TITLE | |
| 5 ><META | |
| 6 NAME="GENERATOR" | |
|
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7 CONTENT="Modular DocBook HTML Stylesheet Version 1.64 |
| 0 | 8 "><LINK |
| 9 REL="HOME" | |
| 10 TITLE="SDL Library Documentation" | |
| 11 HREF="index.html"><LINK | |
| 12 REL="UP" | |
| 13 TITLE="Examples" | |
| 14 HREF="guideexamples.html"><LINK | |
| 15 REL="PREVIOUS" | |
| 16 TITLE="Examples" | |
| 17 HREF="guideexamples.html"><LINK | |
| 18 REL="NEXT" | |
| 19 TITLE="Event Examples" | |
| 20 HREF="guideeventexamples.html"></HEAD | |
| 21 ><BODY | |
| 22 CLASS="SECT1" | |
| 23 BGCOLOR="#FFF8DC" | |
| 24 TEXT="#000000" | |
| 25 LINK="#0000ee" | |
| 26 VLINK="#551a8b" | |
| 27 ALINK="#ff0000" | |
| 28 ><DIV | |
| 29 CLASS="NAVHEADER" | |
| 30 ><TABLE | |
| 31 WIDTH="100%" | |
| 32 BORDER="0" | |
| 33 CELLPADDING="0" | |
| 34 CELLSPACING="0" | |
| 35 ><TR | |
| 36 ><TH | |
| 37 COLSPAN="3" | |
| 38 ALIGN="center" | |
| 39 >SDL Library Documentation</TH | |
| 40 ></TR | |
| 41 ><TR | |
| 42 ><TD | |
| 43 WIDTH="10%" | |
| 44 ALIGN="left" | |
| 45 VALIGN="bottom" | |
| 46 ><A | |
| 47 HREF="guideexamples.html" | |
| 48 >Prev</A | |
| 49 ></TD | |
| 50 ><TD | |
| 51 WIDTH="80%" | |
| 52 ALIGN="center" | |
| 53 VALIGN="bottom" | |
| 54 >Chapter 4. Examples</TD | |
| 55 ><TD | |
| 56 WIDTH="10%" | |
| 57 ALIGN="right" | |
| 58 VALIGN="bottom" | |
| 59 ><A | |
| 60 HREF="guideeventexamples.html" | |
| 61 >Next</A | |
| 62 ></TD | |
| 63 ></TR | |
| 64 ></TABLE | |
| 65 ><HR | |
| 66 ALIGN="LEFT" | |
| 67 WIDTH="100%"></DIV | |
| 68 ><DIV | |
| 69 CLASS="SECT1" | |
| 70 ><H1 | |
| 71 CLASS="SECT1" | |
| 72 ><A | |
| 73 NAME="GUIDEVIDEOEXAMPLES" | |
| 74 >Video Examples</A | |
| 75 ></H1 | |
| 76 ><P | |
| 77 ></P | |
| 78 ><DIV | |
| 79 CLASS="SECT2" | |
| 80 ><H2 | |
| 81 CLASS="SECT2" | |
| 82 ><A | |
|
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83 NAME="AEN375" |
| 0 | 84 >Initializing the video display</A |
| 85 ></H2 | |
| 86 ><P | |
| 87 ><PRE | |
| 88 CLASS="PROGRAMLISTING" | |
| 89 > SDL_Surface *screen; | |
| 90 | |
| 91 /* Initialize the SDL library */ | |
| 92 if( SDL_Init(SDL_INIT_VIDEO) < 0 ) { | |
| 93 fprintf(stderr, | |
| 94 "Couldn't initialize SDL: %s\n", SDL_GetError()); | |
| 95 exit(1); | |
| 96 } | |
| 97 | |
| 98 /* Clean up on exit */ | |
| 99 atexit(SDL_Quit); | |
| 100 | |
| 101 /* Initialize the display in a 640x480 8-bit palettized mode */ | |
| 102 screen = SDL_SetVideoMode(640, 480, 8, SDL_SWSURFACE); | |
| 103 if ( screen == NULL ) { | |
| 104 fprintf(stderr, "Couldn't set 640x480x8 video mode: %s\n", | |
| 105 SDL_GetError()); | |
| 106 exit(1); | |
| 107 }</PRE | |
| 108 ></P | |
| 109 ></DIV | |
| 110 ><DIV | |
| 111 CLASS="SECT2" | |
| 112 ><H2 | |
| 113 CLASS="SECT2" | |
| 114 ><A | |
|
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115 NAME="AEN379" |
| 0 | 116 >Initializing the best video mode</A |
| 117 ></H2 | |
| 118 ><P | |
| 119 ><PRE | |
| 120 CLASS="PROGRAMLISTING" | |
| 121 > /* Have a preference for 8-bit, but accept any depth */ | |
| 122 screen = SDL_SetVideoMode(640, 480, 8, SDL_SWSURFACE|SDL_ANYFORMAT); | |
| 123 if ( screen == NULL ) { | |
| 124 fprintf(stderr, "Couldn't set 640x480x8 video mode: %s\n", | |
| 125 SDL_GetError()); | |
| 126 exit(1); | |
| 127 } | |
| 128 printf("Set 640x480 at %d bits-per-pixel mode\n", | |
| 129 screen->format->BitsPerPixel);</PRE | |
| 130 ></P | |
| 131 ></DIV | |
| 132 ><DIV | |
| 133 CLASS="SECT2" | |
| 134 ><H2 | |
| 135 CLASS="SECT2" | |
| 136 ><A | |
|
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diff
changeset
|
137 NAME="AEN383" |
| 0 | 138 >Loading and displaying a BMP file</A |
| 139 ></H2 | |
| 140 ><P | |
| 141 ><PRE | |
| 142 CLASS="PROGRAMLISTING" | |
| 143 > SDL_Surface *image; | |
| 144 SDL_Rect dest; | |
| 145 int ncolors, i; | |
| 146 SDL_Color *colors; | |
| 147 | |
| 148 /* Load the BMP file into a surface */ | |
| 149 image = SDL_LoadBMP("sample.bmp"); | |
| 150 if ( image == NULL ) { | |
| 151 fprintf(stderr, "Couldn't load sample.bmp: %s\n", | |
| 152 SDL_GetError()); | |
| 153 return; | |
| 154 } | |
| 155 | |
| 156 /* Set the display colors -- SDL_SetColors() only does something on | |
| 157 palettized displays, but it doesn't hurt anything on HiColor or | |
| 158 TrueColor displays. | |
| 159 If the display colors have already been set, this step can be | |
| 160 skipped, and the library will automatically map the image to | |
| 161 the current display colors. | |
| 162 */ | |
| 163 if ( image->format->palette ) { | |
| 164 ncolors = image->format->palette->ncolors; | |
| 165 colors = (SDL_Color *)malloc(ncolors*sizeof(SDL_Color)); | |
| 166 memcpy(colors, image->format->palette->colors, ncolors); | |
| 167 } | |
| 168 else { | |
| 169 int r, g, b; | |
| 170 | |
| 171 /* Allocate 256 color palette */ | |
| 172 ncolors = 256; | |
| 173 colors = (SDL_Color *)malloc(ncolors*sizeof(SDL_Color)); | |
| 174 | |
| 175 /* Set a 3,3,2 color cube */ | |
| 176 for ( r=0; r<8; ++r ) { | |
| 177 for ( g=0; g<8; ++g ) { | |
| 178 for ( b=0; b<4; ++b ) { | |
| 179 i = ((r<<5)|(g<<2)|b); | |
| 180 colors[i].r = r<<5; | |
| 181 colors[i].g = g<<5; | |
| 182 colors[i].b = b<<6; | |
| 183 } | |
| 184 } | |
| 185 } | |
| 186 /* Note: A better way of allocating the palette might be | |
| 187 to calculate the frequency of colors in the image | |
| 188 and create a palette based on that information. | |
| 189 */ | |
| 190 } | |
| 191 /* Set colormap, try for all the colors, but don't worry about it */ | |
| 192 SDL_SetColors(screen, colors, 0, ncolors); | |
| 193 free(colors); | |
| 194 | |
| 195 /* Blit onto the screen surface */ | |
| 196 dest.x = 0; | |
| 197 dest.y = 0; | |
| 198 dest.w = image->w; | |
| 199 dest.h = image->h; | |
| 200 SDL_BlitSurface(image, NULL, screen, &dest); | |
| 201 | |
| 202 SDL_UpdateRects(screen, 1, &dest); | |
| 203 | |
| 204 /* Free the allocated BMP surface */ | |
| 205 SDL_FreeSurface(image); | |
| 206 return;</PRE | |
| 207 ></P | |
| 208 ></DIV | |
| 209 ><DIV | |
| 210 CLASS="SECT2" | |
| 211 ><H2 | |
| 212 CLASS="SECT2" | |
| 213 ><A | |
|
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parents:
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diff
changeset
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214 NAME="AEN387" |
| 0 | 215 >Drawing directly to the display</A |
| 216 ></H2 | |
| 217 ><P | |
| 218 ><PRE | |
| 219 CLASS="PROGRAMLISTING" | |
| 220 > /* Code to set a yellow pixel at the center of the screen */ | |
| 221 | |
| 222 Sint32 X, Y; | |
| 223 Uint32 pixel; | |
| 224 Uint8 *bits, bpp; | |
| 225 | |
| 226 /* Map the color yellow to this display (R=0xFF, G=0xFF, B=0x00) | |
| 227 Note: If the display is palettized, you must set the palette first. | |
| 228 */ | |
| 229 pixel = SDL_MapRGB(screen->format, 0xFF, 0xFF, 0x00); | |
| 230 | |
| 231 /* Calculate the framebuffer offset of the center of the screen */ | |
| 232 if ( SDL_MUSTLOCK(screen) ) { | |
| 233 if ( SDL_LockSurface(screen) < 0 ) | |
| 234 return; | |
| 235 } | |
| 236 bpp = screen->format->BytesPerPixel; | |
| 237 X = screen->w/2; | |
| 238 Y = screen->h/2; | |
| 239 bits = ((Uint8 *)screen->pixels)+Y*screen->pitch+X*bpp; | |
| 240 | |
| 241 /* Set the pixel */ | |
| 242 switch(bpp) { | |
| 243 case 1: | |
| 244 *((Uint8 *)(bits)) = (Uint8)pixel; | |
| 245 break; | |
| 246 case 2: | |
| 247 *((Uint16 *)(bits)) = (Uint16)pixel; | |
| 248 break; | |
| 249 case 3: { /* Format/endian independent */ | |
| 250 Uint8 r, g, b; | |
| 251 | |
| 252 r = (pixel>>screen->format->Rshift)&0xFF; | |
| 253 g = (pixel>>screen->format->Gshift)&0xFF; | |
| 254 b = (pixel>>screen->format->Bshift)&0xFF; | |
| 255 *((bits)+screen->format->Rshift/8) = r; | |
| 256 *((bits)+screen->format->Gshift/8) = g; | |
| 257 *((bits)+screen->format->Bshift/8) = b; | |
| 258 } | |
| 259 break; | |
| 260 case 4: | |
| 261 *((Uint32 *)(bits)) = (Uint32)pixel; | |
| 262 break; | |
| 263 } | |
| 264 | |
| 265 /* Update the display */ | |
| 266 if ( SDL_MUSTLOCK(screen) ) { | |
| 267 SDL_UnlockSurface(screen); | |
| 268 } | |
| 269 SDL_UpdateRect(screen, X, Y, 1, 1); | |
| 270 | |
| 271 return;</PRE | |
| 272 ></P | |
| 273 ></DIV | |
| 274 ><DIV | |
| 275 CLASS="SECT2" | |
| 276 ><H2 | |
| 277 CLASS="SECT2" | |
| 278 ><A | |
|
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Sam Lantinga <slouken@lokigames.com>
parents:
0
diff
changeset
|
279 NAME="AEN391" |
| 0 | 280 >Fastest possible surface blit</A |
| 281 ></H2 | |
| 282 ><P | |
| 283 >There are three different ways you can draw an image to the screen: | |
| 284 <P | |
| 285 ></P | |
| 286 ><TABLE | |
| 287 BORDER="0" | |
| 288 ><TBODY | |
| 289 ><TR | |
| 290 ><TD | |
| 291 >1.Create a surface and use <A | |
| 292 HREF="sdlblitsurface.html" | |
| 293 ><TT | |
| 294 CLASS="FUNCTION" | |
| 295 >SDL_BlitSurface</TT | |
| 296 ></A | |
| 297 > to blit it to the screen</TD | |
| 298 ></TR | |
| 299 ><TR | |
| 300 ><TD | |
| 301 >2.Create the video surface in system memory and call <A | |
| 302 HREF="sdlupdaterect.html" | |
| 303 ><TT | |
| 304 CLASS="FUNCTION" | |
| 305 >SDL_UpdateRect</TT | |
| 306 ></A | |
| 307 ></TD | |
| 308 ></TR | |
| 309 ><TR | |
| 310 ><TD | |
| 311 >3.Create the video surface in video memory and call <A | |
| 312 HREF="sdllocksurface.html" | |
| 313 ><TT | |
| 314 CLASS="FUNCTION" | |
| 315 >SDL_LockSurface</TT | |
| 316 ></A | |
| 317 ></TD | |
| 318 ></TR | |
| 319 ></TBODY | |
| 320 ></TABLE | |
| 321 ><P | |
| 322 ></P | |
| 323 > | |
| 324 The best way to do this is to combine methods: | |
| 325 <PRE | |
| 326 CLASS="PROGRAMLISTING" | |
| 327 >#include <stdio.h> | |
| 328 #include <stdlib.h> | |
| 329 #include "SDL.h" | |
| 330 #include "SDL_timer.h" | |
| 331 | |
| 332 void ComplainAndExit(void) | |
| 333 { | |
| 334 fprintf(stderr, "Problem: %s\n", SDL_GetError()); | |
| 335 exit(1); | |
| 336 } | |
| 337 | |
| 338 int main(int argc, char *argv[]) | |
| 339 { | |
| 340 SDL_PixelFormat fmt; | |
| 341 SDL_Surface *screen, *locked; | |
| 342 SDL_Surface *imagebmp, *image; | |
| 343 SDL_Rect dstrect; | |
| 344 int i; | |
| 345 Uint8 *buffer; | |
| 346 | |
| 347 /* Initialize SDL */ | |
| 348 if ( SDL_Init(SDL_INIT_VIDEO) < 0 ) { | |
| 349 ComplainAndExit(); | |
| 350 } | |
| 351 atexit(SDL_Quit); | |
| 352 | |
| 353 /* Load a BMP image into a surface */ | |
| 354 imagebmp = SDL_LoadBMP("image.bmp"); | |
| 355 if ( imagebmp == NULL ) { | |
| 356 ComplainAndExit(); | |
| 357 } | |
| 358 | |
| 359 /* Set the video mode (640x480 at native depth) */ | |
| 360 screen = SDL_SetVideoMode(640, 480, 0, SDL_HWSURFACE|SDL_FULLSCREEN); | |
| 361 if ( screen == NULL ) { | |
| 362 ComplainAndExit(); | |
| 363 } | |
| 364 | |
| 365 /* Set the video colormap */ | |
| 366 if ( imagebmp->format->palette != NULL ) { | |
| 367 SDL_SetColors(screen, | |
| 368 imagebmp->format->palette->colors, 0, | |
| 369 imagebmp->format->palette->ncolors); | |
| 370 } | |
| 371 | |
| 372 /* Convert the image to the video format (maps colors) */ | |
| 373 image = SDL_DisplayFormat(imagebmp); | |
| 374 SDL_FreeSurface(imagebmp); | |
| 375 if ( image == NULL ) { | |
| 376 ComplainAndExit(); | |
| 377 } | |
| 378 | |
| 379 /* Draw bands of color on the raw surface */ | |
| 380 if ( SDL_MUSTLOCK(screen) ) { | |
| 381 if ( SDL_LockSurface(screen) < 0 ) | |
| 382 ComplainAndExit(); | |
| 383 } | |
| 384 buffer=(Uint8 *)screen->pixels; | |
| 385 for ( i=0; i<screen->h; ++i ) { | |
| 386 memset(buffer,(i*255)/screen->h, | |
| 387 screen->w*screen->format->BytesPerPixel); | |
| 388 buffer += screen->pitch; | |
| 389 } | |
| 390 if ( SDL_MUSTLOCK(screen) ) { | |
| 391 SDL_UnlockSurface(screen); | |
| 392 } | |
| 393 | |
| 394 /* Blit the image to the center of the screen */ | |
| 395 dstrect.x = (screen->w-image->w)/2; | |
| 396 dstrect.y = (screen->h-image->h)/2; | |
| 397 dstrect.w = image->w; | |
| 398 dstrect.h = image->h; | |
| 399 if ( SDL_BlitSurface(image, NULL, screen, &dstrect) < 0 ) { | |
| 400 SDL_FreeSurface(image); | |
| 401 ComplainAndExit(); | |
| 402 } | |
| 403 SDL_FreeSurface(image); | |
| 404 | |
| 405 /* Update the screen */ | |
| 406 SDL_UpdateRects(screen, 1, &dstrect); | |
| 407 | |
| 408 SDL_Delay(5000); /* Wait 5 seconds */ | |
| 409 exit(0); | |
| 410 }</PRE | |
| 411 ></P | |
| 412 ></DIV | |
| 413 ></DIV | |
| 414 ><DIV | |
| 415 CLASS="NAVFOOTER" | |
| 416 ><HR | |
| 417 ALIGN="LEFT" | |
| 418 WIDTH="100%"><TABLE | |
| 419 WIDTH="100%" | |
| 420 BORDER="0" | |
| 421 CELLPADDING="0" | |
| 422 CELLSPACING="0" | |
| 423 ><TR | |
| 424 ><TD | |
| 425 WIDTH="33%" | |
| 426 ALIGN="left" | |
| 427 VALIGN="top" | |
| 428 ><A | |
| 429 HREF="guideexamples.html" | |
| 430 >Prev</A | |
| 431 ></TD | |
| 432 ><TD | |
| 433 WIDTH="34%" | |
| 434 ALIGN="center" | |
| 435 VALIGN="top" | |
| 436 ><A | |
| 437 HREF="index.html" | |
| 438 >Home</A | |
| 439 ></TD | |
| 440 ><TD | |
| 441 WIDTH="33%" | |
| 442 ALIGN="right" | |
| 443 VALIGN="top" | |
| 444 ><A | |
| 445 HREF="guideeventexamples.html" | |
| 446 >Next</A | |
| 447 ></TD | |
| 448 ></TR | |
| 449 ><TR | |
| 450 ><TD | |
| 451 WIDTH="33%" | |
| 452 ALIGN="left" | |
| 453 VALIGN="top" | |
| 454 >Examples</TD | |
| 455 ><TD | |
| 456 WIDTH="34%" | |
| 457 ALIGN="center" | |
| 458 VALIGN="top" | |
| 459 ><A | |
| 460 HREF="guideexamples.html" | |
| 461 >Up</A | |
| 462 ></TD | |
| 463 ><TD | |
| 464 WIDTH="33%" | |
| 465 ALIGN="right" | |
| 466 VALIGN="top" | |
| 467 >Event Examples</TD | |
| 468 ></TR | |
| 469 ></TABLE | |
| 470 ></DIV | |
| 471 ></BODY | |
| 472 ></HTML | |
| 473 > |