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