git.hungrycats.org Git - xscreensaver/blob - hacks/discrete.c

   1 /* -*- Mode: C; tab-width: 4 -*- */
   2 /* discrete --- chaotic mappings */
   3
   4 #if 0
   5 static const char sccsid[] = "@(#)discrete.c    5.00 2000/11/01 xlockmore";
   6 #endif
   7
   8 /*-
   9  * Copyright (c) 1996 by Tim Auckland <Tim.Auckland@Procket.com>
  10  *
  11  * Permission to use, copy, modify, and distribute this software and its
  12  * documentation for any purpose and without fee is hereby granted,
  13  * provided that the above copyright notice appear in all copies and that
  14  * both that copyright notice and this permission notice appear in
  15  * supporting documentation.
  16  *
  17  * This file is provided AS IS with no warranties of any kind.  The author
  18  * shall have no liability with respect to the infringement of copyrights,
  19  * trade secrets or any patents by this file or any part thereof.  In no
  20  * event will the author be liable for any lost revenue or profits or
  21  * other special, indirect and consequential damages.
  22  *
  23  * "discrete" shows a number of fractals based on the "discrete map"
  24  * type of dynamical systems.  They include a different way of looking
  25  * at the HOPALONG system, an inverse julia-set iteration, the "Standard
  26  * Map" and the "Bird in a Thornbush" fractal.
  27  *
  28  * Revision History:
  29  * 01-Nov-2000: Allocation checks
  30  * 31-Jul-1997: Ported to xlockmore-4
  31  * 08-Aug-1996: Adapted from hop.c Copyright (c) 1991 by Patrick J. Naughton.
  32  */
  33
  34 #ifdef STANDALONE
  35 #define MODE_discrete
  36 #define PROGCLASS "Discrete"
  37 #define HACK_INIT init_discrete
  38 #define HACK_DRAW draw_discrete
  39 #define discrete_opts xlockmore_opts
  40 #define DEFAULTS "*delay: 1000 \n" \
  41  "*count: 4096 \n" \
  42  "*cycles: 2500 \n" \
  43  "*ncolors: 100 \n"
  44 #define SMOOTH_COLORS
  45 #include "xlockmore.h"          /* in xscreensaver distribution */
  46 #include "erase.h"
  47 #else /* STANDALONE */
  48 #include "xlock.h"              /* in xlockmore distribution */
  49 #endif /* STANDALONE */
  50
  51 #ifdef MODE_discrete
  52
  53 ModeSpecOpt discrete_opts =
  54 {0, (XrmOptionDescRec *) NULL, 0, (argtype *) NULL, (OptionStruct *) NULL};
  55
  56 #ifdef USE_MODULES
  57 ModStruct   discrete_description =
  58 {"discrete", "init_discrete", "draw_discrete", "release_discrete",
  59  "refresh_discrete", "init_discrete", (char *) NULL, &discrete_opts,
  60  1000, 4096, 2500, 1, 64, 1.0, "",
  61  "Shows various discrete maps", 0, NULL};
  62
  63 #endif
  64
  65 enum ftypes {
  66         SQRT, BIRDIE, STANDARD, TRIG, CUBIC, HENON, AILUJ, HSHOE, DELOG
  67 };
  68
  69 /*#define TEST STANDARD */
  70
  71 #define BIASES 18
  72 static enum ftypes bias[BIASES] =
  73 {
  74         STANDARD, STANDARD, STANDARD, STANDARD,
  75         SQRT, SQRT, SQRT, SQRT,
  76         BIRDIE, BIRDIE, BIRDIE,
  77         AILUJ, AILUJ, AILUJ,
  78         TRIG, TRIG,
  79         CUBIC,
  80         HENON,
  81 };
  82
  83 typedef struct {
  84         int         maxx;
  85         int         maxy;       /* max of the screen */
  86         double      a;
  87         double      b;
  88         double      c;
  89         double      d;
  90         double      e;
  91         double      i;
  92         double      j;          /* discrete parameters */
  93         double      ic;
  94         double      jc;
  95         double      is;
  96         double      js;
  97         int         inc;
  98         int         pix;
  99         enum ftypes op;
 100         int         count;
 101         XPoint     *pointBuffer;        /* pointer for XDrawPoints */
 102 } discretestruct;
 103
 104 static discretestruct *discretes = (discretestruct *) NULL;
 105
 106 void
 107 init_discrete(ModeInfo * mi)
 108 {
 109         double      range;
 110         discretestruct *hp;
 111
 112         if (discretes == NULL) {
 113                 if ((discretes =
 114                      (discretestruct *) calloc(MI_NUM_SCREENS(mi),
 115                                            sizeof (discretestruct))) == NULL)
 116                         return;
 117         }
 118         hp = &discretes[MI_SCREEN(mi)];
 119
 120         hp->maxx = MI_WIDTH(mi);
 121         hp->maxy = MI_HEIGHT(mi);
 122 #ifdef TEST
 123         hp->op = TEST;
 124 #else
 125         hp->op = bias[LRAND() % BIASES];
 126 #endif
 127         switch (hp->op) {
 128                 case HSHOE:
 129                         hp->ic = 0;
 130                         hp->jc = 0;
 131                         hp->is = hp->maxx / (4);
 132                         hp->js = hp->maxy / (4);
 133                         hp->a = 0.5;
 134                         hp->b = 0.5;
 135                         hp->c = 0.2;
 136                         hp->d = -1.25;
 137                         hp->e = 1;
 138                         hp->i = hp->j = 0.0;
 139                         break;
 140                 case DELOG:
 141                         hp->ic = 0.5;
 142                         hp->jc = 0.3;
 143                         hp->is = hp->maxx / 1.5;
 144                         hp->js = hp->maxy / 1.5;
 145                         hp->a = 2.176399;
 146                         hp->i = hp->j = 0.01;
 147                         break;
 148                 case HENON:
 149                         hp->jc = ((LRAND() / MAXRAND) * 2.0 - 1.0) * 0.4;
 150                         hp->ic = 1.3 * (1 - (hp->jc * hp->jc) / (0.4 * 0.4));
 151                         hp->is = hp->maxx;
 152                         hp->js = hp->maxy * 1.5;
 153                         hp->a = 1;
 154                         hp->b = 1.4;
 155                         hp->c = 0.3;
 156                         hp->i = hp->j = 0;
 157                         break;
 158                 case SQRT:
 159                         hp->ic = 0;
 160                         hp->jc = 0;
 161                         hp->is = 1;
 162                         hp->js = 1;
 163                         range = sqrt((double) hp->maxx * 2 * hp->maxx * 2 +
 164                                      (double) hp->maxy * 2 * hp->maxy * 2) /
 165                                 (10.0 + LRAND() % 10);
 166
 167                         hp->a = (LRAND() / MAXRAND) * range - range / 2.0;
 168                         hp->b = (LRAND() / MAXRAND) * range - range / 2.0;
 169                         hp->c = (LRAND() / MAXRAND) * range - range / 2.0;
 170                         if (!(LRAND() % 2))
 171                                 hp->c = 0.0;
 172                         hp->i = hp->j = 0.0;
 173                         break;
 174                 case STANDARD:
 175                         hp->ic = M_PI;
 176                         hp->jc = M_PI;
 177                         hp->is = hp->maxx / (M_PI * 2);
 178                         hp->js = hp->maxy / (M_PI * 2);
 179                         hp->a = 0;      /* decay */
 180                         hp->b = (LRAND() / MAXRAND) * 2.0;
 181                         hp->c = 0;
 182                         hp->i = M_PI;
 183                         hp->j = M_PI;
 184                         break;
 185                 case BIRDIE:
 186                         hp->ic = 0;
 187                         hp->jc = 0;
 188                         hp->is = hp->maxx / 2;
 189                         hp->js = hp->maxy / 2;
 190                         hp->a = 1.99 + ((LRAND() / MAXRAND) * 2.0 - 1.0) * 0.2;
 191                         hp->b = 0;
 192                         hp->c = 0.8 + ((LRAND() / MAXRAND) * 2.0 - 1.0) * 0.1;
 193                         hp->i = hp->j = 0;
 194                         break;
 195                 case TRIG:
 196                         hp->a = 5;
 197                         hp->b = 0.5 + ((LRAND() / MAXRAND) * 2.0 - 1.0) * 0.3;
 198                         hp->ic = hp->a;
 199                         hp->jc = 0;
 200                         hp->is = hp->maxx / (hp->b * 20);
 201                         hp->js = hp->maxy / (hp->b * 20);
 202                         hp->i = hp->j = 0;
 203                         break;
 204                 case CUBIC:
 205                         hp->a = 2.77;
 206                         hp->b = 0.1 + ((LRAND() / MAXRAND) * 2.0 - 1.0) * 0.1;
 207                         hp->ic = 0;
 208                         hp->jc = 0;
 209                         hp->is = hp->maxx / 4;
 210                         hp->js = hp->maxy / 4;
 211                         hp->i = hp->j = 0.1;
 212                         break;
 213                 case AILUJ:
 214                         {
 215                                 int         i;
 216                                 double      x, y, xn, yn;
 217
 218                                 hp->ic = 0;
 219                                 hp->jc = 0;
 220                                 hp->is = hp->maxx / 4;
 221                                 hp->js = hp->maxx / 4;
 222                                 do {
 223                                         hp->a = ((LRAND() / MAXRAND) * 2.0 - 1.0) * 1.5 - 0.5;
 224                                         hp->b = ((LRAND() / MAXRAND) * 2.0 - 1.0) * 1.5;
 225                                         x = y = 0;
 226 #define MAXITER 10
 227                                         for (i = 0; i < MAXITER && x * x + y * y < 13; i++) {   /* 'Brot calc */
 228                                                 xn = x * x - y * y + hp->a;
 229                                                 yn = 2 * x * y + hp->b;
 230                                                 x = xn;
 231                                                 y = yn;
 232                                         }
 233                                 } while (i < MAXITER);  /* wait for a connected set */
 234                                 hp->i = hp->j = 0.1;
 235                                 break;
 236                         }
 237         }
 238         hp->pix = 0;
 239         hp->inc = 0;
 240
 241         if (hp->pointBuffer == NULL) {
 242                 hp->pointBuffer = (XPoint *) malloc(sizeof (XPoint) * MI_COUNT(mi));
 243                 /* if fails will check later */
 244         }
 245
 246         /* Clear the background. */
 247         MI_CLEARWINDOW(mi);
 248
 249         XSetForeground(MI_DISPLAY(mi), MI_GC(mi), MI_WHITE_PIXEL(mi));
 250         hp->count = 0;
 251 }
 252
 253
 254 void
 255 draw_discrete(ModeInfo * mi)
 256 {
 257         Display    *dsp = MI_DISPLAY(mi);
 258         Window      win = MI_WINDOW(mi);
 259         double      oldj, oldi;
 260         int         count = MI_COUNT(mi);
 261         int         cycles = MI_CYCLES(mi);
 262         int         k;
 263         XPoint     *xp;
 264         GC          gc = MI_GC(mi);
 265         discretestruct *hp;
 266
 267         if (discretes == NULL)
 268                 return;
 269         hp = &discretes[MI_SCREEN(mi)];
 270         if (hp->pointBuffer == NULL)
 271                 return;
 272
 273         k = count;
 274         xp = hp->pointBuffer;
 275
 276         hp->inc++;
 277
 278         MI_IS_DRAWN(mi) = True;
 279
 280         if (MI_NPIXELS(mi) > 2) {
 281                 XSetForeground(dsp, gc, MI_PIXEL(mi, hp->pix));
 282                 if (++hp->pix >= MI_NPIXELS(mi))
 283                         hp->pix = 0;
 284         }
 285         while (k--) {
 286                 oldj = hp->j;
 287                 oldi = hp->i;
 288                 switch (hp->op) {
 289                         case HSHOE:
 290                                 {
 291                                         int         i;
 292
 293 #if 0
 294                                         if (!k) {
 295                                                 XSetForeground(dsp, gc, MI_BLACK_PIXEL(mi));
 296                                                 XFillRectangle(dsp, win, gc, 0, 0, hp->maxx, hp->maxy);
 297                                                 XSetForeground(dsp, gc, MI_PIXEL(mi, hp->pix));
 298                                         } else
 299 #endif
 300 #define HD
 301 #ifdef HD
 302                                         if (k < count / 4) {
 303                                                 hp->i = ((double) k / count) * 8 - 1;
 304                                                 hp->j = 1;
 305                                         } else if (k < count / 2) {
 306                                                 hp->i = 1;
 307                                                 hp->j = 3 - ((double) k / count) * 8;
 308                                         } else if (k < 3 * count / 4) {
 309                                                 hp->i = 5 - ((double) k / count) * 8;
 310                                                 hp->j = -1;
 311                                         } else {
 312                                                 hp->i = -1;
 313                                                 hp->j = ((double) k / count) * 8 - 7;
 314                                         }
 315                                         for (i = 1; i < (hp->inc % 15); i++) {
 316                                                 oldj = hp->j;
 317                                                 oldi = hp->i;
 318 #endif
 319                                                 hp->i = (hp->a * oldi + hp->b) * oldj;
 320                                                 hp->j = (hp->e - hp->d + hp->c * oldi) * oldj * oldj - hp->c * oldi + hp->d;
 321 #ifdef HD
 322                                         }
 323 #endif
 324                                         break;
 325                                 }
 326                         case DELOG:
 327                                 hp->j = oldi;
 328                                 hp->i = hp->a * oldi * (1 - oldj);
 329                                 break;
 330                         case HENON:
 331                                 hp->i = oldj + hp->a - hp->b * oldi * oldi;
 332                                 hp->j = hp->c * oldi;
 333                                 break;
 334                         case SQRT:
 335                                 if (k) {
 336                                         hp->j = hp->a + hp->i;
 337                                         hp->i = -oldj + (hp->i < 0
 338                                         ? sqrt(fabs(hp->b * (hp->i - hp->c)))
 339                                                          : -sqrt(fabs(hp->b * (hp->i - hp->c))));
 340                                 } else {
 341                                         static int  s = 1;
 342
 343                                         hp->i = s * hp->inc * hp->maxx / cycles / 2;
 344                                         hp->j = hp->a + hp->i;
 345                                         s = -s;
 346                                 }
 347                                 break;
 348                         case STANDARD:
 349                                 if (k) {
 350                                         hp->j = (1 - hp->a) * oldj + hp->b * sin(oldi) + hp->a * hp->c;
 351                                         hp->j = fmod(hp->j + 2 * M_PI, 2 * M_PI);
 352                                         hp->i = oldi + hp->j;
 353                                         hp->i = fmod(hp->i + 2 * M_PI, 2 * M_PI);
 354                                 } else {
 355                                         static int  s = 1;
 356
 357                                         hp->j = M_PI + fmod(s * hp->inc * 2 * M_PI / (cycles - 0.5), M_PI);
 358                                         hp->i = M_PI;
 359                                         s = -s;
 360                                 }
 361                                 break;
 362                         case BIRDIE:
 363                                 hp->j = oldi;
 364                                 hp->i = (1 - hp->c) * cos(M_PI * hp->a * oldj) + hp->c * hp->b;
 365                                 hp->b = oldj;
 366                                 break;
 367                         case TRIG:
 368                                 {
 369                                         double      r2 = oldi * oldi + oldj * oldj;
 370
 371                                         hp->i = hp->a + hp->b * (oldi * cos(r2) - oldj * sin(r2));
 372                                         hp->j = hp->b * (oldj * cos(r2) + oldi * sin(r2));
 373                                 }
 374                                 break;
 375                         case CUBIC:
 376                                 hp->i = oldj;
 377                                 hp->j = hp->a * oldj - oldj * oldj * oldj - hp->b * oldi;
 378                                 break;
 379                         case AILUJ:
 380                                 hp->i = ((LRAND() < MAXRAND / 2) ? -1 : 1) *
 381                                         sqrt(((oldi - hp->a) +
 382                                               sqrt((oldi - hp->a) * (oldi - hp->a) + (oldj - hp->b) * (oldj - hp->b))) / 2);
 383                                 if (hp->i < 0.00000001 && hp->i > -0.00000001)
 384                                         hp->i = (hp->i > 0.0) ? 0.00000001 : -0.00000001;
 385                                 hp->j = (oldj - hp->b) / (2 * hp->i);
 386                                 break;
 387                 }
 388                 xp->x = hp->maxx / 2 + (int) ((hp->i - hp->ic) * hp->is);
 389                 xp->y = hp->maxy / 2 - (int) ((hp->j - hp->jc) * hp->js);
 390                 xp++;
 391         }
 392         XDrawPoints(dsp, win, gc, hp->pointBuffer, count, CoordModeOrigin);
 393         if (++hp->count > cycles) {
 394 #ifdef STANDALONE
 395                 erase_full_window(MI_DISPLAY(mi), MI_WINDOW(mi));
 396 #endif /* STANDALONE */
 397                 init_discrete(mi);
 398         }
 399 }
 400
 401 void
 402 release_discrete(ModeInfo * mi)
 403 {
 404         if (discretes != NULL) {
 405                 int         screen;
 406
 407                 for (screen = 0; screen < MI_NUM_SCREENS(mi); screen++) {
 408                         discretestruct *hp = &discretes[screen];
 409
 410                         if (hp->pointBuffer != NULL) {
 411                                 (void) free((void *) hp->pointBuffer);
 412                                 /* hp->pointBuffer = NULL; */
 413                         }
 414                 }
 415                 (void) free((void *) discretes);
 416                 discretes = (discretestruct *) NULL;
 417         }
 418 }
 419
 420 void
 421 refresh_discrete(ModeInfo * mi)
 422 {
 423         MI_CLEARWINDOW(mi);
 424 }
 425
 426 #endif /* MODE_discrete */