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. */
quit(int rc)58 static void quit(int rc)
59 {
60 SDL_Quit();
61 exit(rc);
62 }
63
sdlerr(char * when)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 */
make_bg(SDL_Surface * screen,int startcol)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 */
hflip(SDL_Surface * s)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
main(int argc,char ** argv)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