Mercurial > sdl-ios-xcode
annotate docs/html/guidevideoexamples.html @ 693:6c119628180d
Date: Sat, 16 Aug 2003 16:22:56 +0300
From: "Mike Gorchak"
Subject: Package building for QNX6
I'm just completed the package description file for QNX6 - qpg, it is like a\
.spec files for Linux. Please place SDL.qpg.in file in the root of the proj\
ect, where .spec file is placed. And sdl12qpg.diff - just adding the SDL.qpg\
.in. The same for the SDL_image. I'm planning to add .qpg files creation for\
all SDL* projects.
As for shared library building for QNX6. It is very hard to improve the exis\
ting libtool code to support QNX shared libraries. Much easyiest is to remov\
e libtool.m4 code from the acinclude.m4 for those persons, who building shar\
ed libraries for QNX6. I'm described all what they need to do with .so under\
QNX6 in the README.QNX file. And 90% of people used the precompiled librari\
es, so I think it is not big problem :)
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Sat, 23 Aug 2003 23:25:46 +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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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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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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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 > |