1 /* 2 * testpalette.c 3 * 4 * A simple test of runtime palette modification for animation 5 * (using the SDL_SetPalette() API). 6 */ 7 8 #include <stdio.h> 9 #include <stdlib.h> 10 #include <string.h> 11 #include <math.h> 12 13 /* This isn't in the Windows headers */ 14 #ifndef M_PI 15 #define M_PI 3.14159265358979323846 16 #endif 17 18 #include "SDL.h" 19 20 /* screen size */ 21 #define SCRW 640 22 #define SCRH 480 23 24 #define NBOATS 5 25 #define SPEED 2 26 27 #ifndef MIN 28 #define MIN(a, b) ((a) < (b) ? (a) : (b)) 29 #endif 30 #ifndef MAX 31 #define MAX(a, b) ((a) > (b) ? (a) : (b)) 32 #endif 33 34 /* 35 * wave colours: Made by taking a narrow cross-section of a wave picture 36 * in Gimp, saving in PPM ascii format and formatting with Emacs macros. 37 */ 38 static SDL_Color wavemap[] = { 39 {0,2,103}, {0,7,110}, {0,13,117}, {0,19,125}, 40 {0,25,133}, {0,31,141}, {0,37,150}, {0,43,158}, 41 {0,49,166}, {0,55,174}, {0,61,182}, {0,67,190}, 42 {0,73,198}, {0,79,206}, {0,86,214}, {0,96,220}, 43 {5,105,224}, {12,112,226}, {19,120,227}, {26,128,229}, 44 {33,135,230}, {40,143,232}, {47,150,234}, {54,158,236}, 45 {61,165,238}, {68,173,239}, {75,180,241}, {82,188,242}, 46 {89,195,244}, {96,203,246}, {103,210,248}, {112,218,250}, 47 {124,224,250}, {135,226,251}, {146,229,251}, {156,231,252}, 48 {167,233,252}, {178,236,252}, {189,238,252}, {200,240,252}, 49 {211,242,252}, {222,244,252}, {233,247,252}, {242,249,252}, 50 {237,250,252}, {209,251,252}, {174,251,252}, {138,252,252}, 51 {102,251,252}, {63,250,252}, {24,243,252}, {7,225,252}, 52 {4,203,252}, {3,181,252}, {2,158,252}, {1,136,251}, 53 {0,111,248}, {0,82,234}, {0,63,213}, {0,50,192}, 54 {0,39,172}, {0,28,152}, {0,17,132}, {0,7,114} 55 }; 56 57 /* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */ 58 static void quit(int rc) 59 { 60 SDL_Quit(); 61 exit(rc); 62 } 63 64 static void sdlerr(char *when) 65 { 66 fprintf(stderr, "SDL error: %s: %s\n", when, SDL_GetError()); 67 quit(1); 68 } 69 70 /* create a background surface */ 71 static SDL_Surface *make_bg(SDL_Surface *screen, int startcol) 72 { 73 int i; 74 SDL_Surface *bg = SDL_CreateRGBSurface(SDL_SWSURFACE, screen->w, screen->h, 75 8, 0, 0, 0, 0); 76 if(!bg) 77 sdlerr("creating background surface"); 78 79 /* set the palette to the logical screen palette so that blits 80 won't be translated */ 81 SDL_SetColors(bg, screen->format->palette->colors, 0, 256); 82 83 /* Make a wavy background pattern using colours 0-63 */ 84 if(SDL_LockSurface(bg) < 0) 85 sdlerr("locking background"); 86 for(i = 0; i < SCRH; i++) { 87 Uint8 *p = (Uint8 *)bg->pixels + i * bg->pitch; 88 int j, d; 89 d = 0; 90 for(j = 0; j < SCRW; j++) { 91 int v = MAX(d, -2); 92 v = MIN(v, 2); 93 if(i > 0) 94 v += p[-bg->pitch] + 65 - startcol; 95 p[j] = startcol + (v & 63); 96 d += ((rand() >> 3) % 3) - 1; 97 } 98 } 99 SDL_UnlockSurface(bg); 100 return(bg); 101 } 102 103 /* 104 * Return a surface flipped horisontally. Only works for 8bpp; 105 * extension to arbitrary bitness is left as an exercise for the reader. 106 */ 107 static SDL_Surface *hflip(SDL_Surface *s) 108 { 109 int i; 110 SDL_Surface *z = SDL_CreateRGBSurface(SDL_SWSURFACE, s->w, s->h, 8, 111 0, 0, 0, 0); 112 /* copy palette */ 113 SDL_SetColors(z, s->format->palette->colors, 114 0, s->format->palette->ncolors); 115 if(SDL_LockSurface(s) < 0 || SDL_LockSurface(z) < 0) 116 sdlerr("locking flip images"); 117 118 for(i = 0; i < s->h; i++) { 119 int j; 120 Uint8 *from = (Uint8 *)s->pixels + i * s->pitch; 121 Uint8 *to = (Uint8 *)z->pixels + i * z->pitch + s->w - 1; 122 for(j = 0; j < s->w; j++) 123 to[-j] = from[j]; 124 } 125 126 SDL_UnlockSurface(z); 127 SDL_UnlockSurface(s); 128 return z; 129 } 130 131 int main(int argc, char **argv) 132 { 133 SDL_Color cmap[256]; 134 SDL_Surface *screen; 135 SDL_Surface *bg; 136 SDL_Surface *boat[2]; 137 unsigned vidflags = 0; 138 unsigned start; 139 int fade_max = 400; 140 int fade_level, fade_dir; 141 int boatcols, frames, i, red; 142 int boatx[NBOATS], boaty[NBOATS], boatdir[NBOATS]; 143 int gamma_fade = 0; 144 int gamma_ramp = 0; 145 146 if(SDL_Init(SDL_INIT_VIDEO) < 0) 147 sdlerr("initialising SDL"); 148 149 while(--argc) { 150 ++argv; 151 if(strcmp(*argv, "-hw") == 0) 152 vidflags |= SDL_HWSURFACE; 153 else if(strcmp(*argv, "-fullscreen") == 0) 154 vidflags |= SDL_FULLSCREEN; 155 else if(strcmp(*argv, "-nofade") == 0) 156 fade_max = 1; 157 else if(strcmp(*argv, "-gamma") == 0) 158 gamma_fade = 1; 159 else if(strcmp(*argv, "-gammaramp") == 0) 160 gamma_ramp = 1; 161 else { 162 fprintf(stderr, 163 "usage: testpalette " 164 " [-hw] [-fullscreen] [-nofade] [-gamma] [-gammaramp]\n"); 165 quit(1); 166 } 167 } 168 169 /* Ask explicitly for 8bpp and a hardware palette */ 170 if((screen = SDL_SetVideoMode(SCRW, SCRH, 8, vidflags | SDL_HWPALETTE)) == NULL) { 171 fprintf(stderr, "error setting %dx%d 8bpp indexed mode: %s\n", 172 SCRW, SCRH, SDL_GetError()); 173 quit(1); 174 } 175 176 if (vidflags & SDL_FULLSCREEN) SDL_ShowCursor (SDL_FALSE); 177 178 if((boat[0] = SDL_LoadBMP("sail.bmp")) == NULL) 179 sdlerr("loading sail.bmp"); 180 /* We've chosen magenta (#ff00ff) as colour key for the boat */ 181 SDL_SetColorKey(boat[0], SDL_SRCCOLORKEY | SDL_RLEACCEL, 182 SDL_MapRGB(boat[0]->format, 0xff, 0x00, 0xff)); 183 boatcols = boat[0]->format->palette->ncolors; 184 boat[1] = hflip(boat[0]); 185 SDL_SetColorKey(boat[1], SDL_SRCCOLORKEY | SDL_RLEACCEL, 186 SDL_MapRGB(boat[1]->format, 0xff, 0x00, 0xff)); 187 188 /* 189 * First set the physical screen palette to black, so the user won't 190 * see our initial drawing on the screen. 191 */ 192 memset(cmap, 0, sizeof(cmap)); 193 SDL_SetPalette(screen, SDL_PHYSPAL, cmap, 0, 256); 194 195 /* 196 * Proper palette management is important when playing games with the 197 * colormap. We have divided the palette as follows: 198 * 199 * index 0..(boatcols-1): used for the boat 200 * index boatcols..(boatcols+63): used for the waves 201 */ 202 SDL_SetPalette(screen, SDL_LOGPAL, 203 boat[0]->format->palette->colors, 0, boatcols); 204 SDL_SetPalette(screen, SDL_LOGPAL, wavemap, boatcols, 64); 205 206 /* 207 * Now the logical screen palette is set, and will remain unchanged. 208 * The boats already have the same palette so fast blits can be used. 209 */ 210 memcpy(cmap, screen->format->palette->colors, 256 * sizeof(SDL_Color)); 211 212 /* save the index of the red colour for later */ 213 red = SDL_MapRGB(screen->format, 0xff, 0x00, 0x00); 214 215 bg = make_bg(screen, boatcols); /* make a nice wavy background surface */ 216 217 /* initial screen contents */ 218 if(SDL_BlitSurface(bg, NULL, screen, NULL) < 0) 219 sdlerr("blitting background to screen"); 220 SDL_Flip(screen); /* actually put the background on screen */ 221 222 /* determine initial boat placements */ 223 for(i = 0; i < NBOATS; i++) { 224 boatx[i] = (rand() % (SCRW + boat[0]->w)) - boat[0]->w; 225 boaty[i] = i * (SCRH - boat[0]->h) / (NBOATS - 1); 226 boatdir[i] = ((rand() >> 5) & 1) * 2 - 1; 227 } 228 229 start = SDL_GetTicks(); 230 frames = 0; 231 fade_dir = 1; 232 fade_level = 0; 233 do { 234 SDL_Event e; 235 SDL_Rect updates[NBOATS]; 236 SDL_Rect r; 237 int redphase; 238 239 /* A small event loop: just exit on any key or mouse button event */ 240 while(SDL_PollEvent(&e)) { 241 if(e.type == SDL_KEYDOWN || e.type == SDL_QUIT 242 || e.type == SDL_MOUSEBUTTONDOWN) { 243 if(fade_dir < 0) 244 fade_level = 0; 245 fade_dir = -1; 246 } 247 } 248 249 /* move boats */ 250 for(i = 0; i < NBOATS; i++) { 251 int old_x = boatx[i]; 252 /* update boat position */ 253 boatx[i] += boatdir[i] * SPEED; 254 if(boatx[i] <= -boat[0]->w || boatx[i] >= SCRW) 255 boatdir[i] = -boatdir[i]; 256 257 /* paint over the old boat position */ 258 r.x = old_x; 259 r.y = boaty[i]; 260 r.w = boat[0]->w; 261 r.h = boat[0]->h; 262 if(SDL_BlitSurface(bg, &r, screen, &r) < 0) 263 sdlerr("blitting background"); 264 265 /* construct update rectangle (bounding box of old and new pos) */ 266 updates[i].x = MIN(old_x, boatx[i]); 267 updates[i].y = boaty[i]; 268 updates[i].w = boat[0]->w + SPEED; 269 updates[i].h = boat[0]->h; 270 /* clip update rectangle to screen */ 271 if(updates[i].x < 0) { 272 updates[i].w += updates[i].x; 273 updates[i].x = 0; 274 } 275 if(updates[i].x + updates[i].w > SCRW) 276 updates[i].w = SCRW - updates[i].x; 277 } 278 279 for(i = 0; i < NBOATS; i++) { 280 /* paint boat on new position */ 281 r.x = boatx[i]; 282 r.y = boaty[i]; 283 if(SDL_BlitSurface(boat[(boatdir[i] + 1) / 2], NULL, 284 screen, &r) < 0) 285 sdlerr("blitting boat"); 286 } 287 288 /* cycle wave palette */ 289 for(i = 0; i < 64; i++) 290 cmap[boatcols + ((i + frames) & 63)] = wavemap[i]; 291 292 if(fade_dir) { 293 /* Fade the entire palette in/out */ 294 fade_level += fade_dir; 295 296 if(gamma_fade) { 297 /* Fade linearly in gamma level (lousy) */ 298 float level = (float)fade_level / fade_max; 299 if(SDL_SetGamma(level, level, level) < 0) 300 sdlerr("setting gamma"); 301 302 } else if(gamma_ramp) { 303 /* Fade using gamma ramp (better) */ 304 Uint16 ramp[256]; 305 for(i = 0; i < 256; i++) 306 ramp[i] = (i * fade_level / fade_max) << 8; 307 if(SDL_SetGammaRamp(ramp, ramp, ramp) < 0) 308 sdlerr("setting gamma ramp"); 309 310 } else { 311 /* Fade using direct palette manipulation (best) */ 312 memcpy(cmap, screen->format->palette->colors, 313 boatcols * sizeof(SDL_Color)); 314 for(i = 0; i < boatcols + 64; i++) { 315 cmap[i].r = cmap[i].r * fade_level / fade_max; 316 cmap[i].g = cmap[i].g * fade_level / fade_max; 317 cmap[i].b = cmap[i].b * fade_level / fade_max; 318 } 319 } 320 if(fade_level == fade_max) 321 fade_dir = 0; 322 } 323 324 /* pulse the red colour (done after the fade, for a night effect) */ 325 redphase = frames % 64; 326 cmap[red].r = (int)(255 * sin(redphase * M_PI / 63)); 327 328 SDL_SetPalette(screen, SDL_PHYSPAL, cmap, 0, boatcols + 64); 329 330 /* update changed areas of the screen */ 331 SDL_UpdateRects(screen, NBOATS, updates); 332 frames++; 333 } while(fade_level > 0); 334 335 printf("%d frames, %.2f fps\n", 336 frames, 1000.0 * frames / (SDL_GetTicks() - start)); 337 338 if (vidflags & SDL_FULLSCREEN) SDL_ShowCursor (SDL_TRUE); 339 SDL_Quit(); 340 return 0; 341 } 342 343
