test/testpalette.c
author Sam Lantinga <slouken@libsdl.org>
Mon, 21 Sep 2009 07:32:26 +0000
branchSDL-1.2
changeset 4209 62e86ab81e3c
parent 1815 871090feb7ad
child 1662 782fd950bd46
child 1895 c121d94672cb
permissions -rw-r--r--
Fixed bug #570

SDL_SemWaitTimeout in src/thread/generic/SDL_syssem.c line 179 (SVN trunk):

--sem->count;

should be

if (retval == 0) {
--sem->count;
}

Without this, sem->count will underflow on timeout effectively breaking the
semaphore. It appears that the implementation has been wrong since the initial
revision.
     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