test/testpalette.c
author Sam Lantinga <slouken@libsdl.org>
Tue, 18 Dec 2001 00:18:49 +0000
changeset 257 9ac9ab945955
parent 0 74212992fb08
child 1151 be9c9c8f6d53
permissions -rw-r--r--
*** empty log message ***
     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