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 <tda10.geo@yahoo.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 DEFAULTS        "*delay: 20000 \n" \
  37                                         "*count:  4096 \n" \
  38                                         "*cycles: 2500 \n" \
  39                                         "*ncolors: 100 \n" \
  40                                         "*fpsSolid: true \n" \
  41                                     "*ignoreRotation: True \n" \
  42
  43 # define SMOOTH_COLORS
  44 # define discrete_handle_event 0
  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 ENTRYPOINT 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
 103     int sqrt_sign, std_sign;
 104
 105 #ifdef STANDALONE
 106   eraser_state *eraser;
 107 #endif
 108
 109 } discretestruct;
 110
 111 static discretestruct *discretes = (discretestruct *) NULL;
 112
 113 ENTRYPOINT void
 114 init_discrete (ModeInfo * mi)
 115 {
 116         double      range;
 117         discretestruct *hp;
 118
 119         if (discretes == NULL) {
 120                 if ((discretes =
 121                      (discretestruct *) calloc(MI_NUM_SCREENS(mi),
 122                                            sizeof (discretestruct))) == NULL)
 123                         return;
 124         }
 125         hp = &discretes[MI_SCREEN(mi)];
 126
 127         hp->maxx = MI_WIDTH(mi);
 128         hp->maxy = MI_HEIGHT(mi);
 129 #ifdef TEST
 130         hp->op = TEST;
 131 #else
 132         hp->op = bias[LRAND() % BIASES];
 133 #endif
 134         switch (hp->op) {
 135                 case HSHOE:
 136                         hp->ic = 0;
 137                         hp->jc = 0;
 138                         hp->is = hp->maxx / (4);
 139                         hp->js = hp->maxy / (4);
 140                         hp->a = 0.5;
 141                         hp->b = 0.5;
 142                         hp->c = 0.2;
 143                         hp->d = -1.25;
 144                         hp->e = 1;
 145                         hp->i = hp->j = 0.0;
 146                         break;
 147                 case DELOG:
 148                         hp->ic = 0.5;
 149                         hp->jc = 0.3;
 150                         hp->is = hp->maxx / 1.5;
 151                         hp->js = hp->maxy / 1.5;
 152                         hp->a = 2.176399;
 153                         hp->i = hp->j = 0.01;
 154                         break;
 155                 case HENON:
 156                         hp->jc = ((LRAND() / MAXRAND) * 2.0 - 1.0) * 0.4;
 157                         hp->ic = 1.3 * (1 - (hp->jc * hp->jc) / (0.4 * 0.4));
 158                         hp->is = hp->maxx;
 159                         hp->js = hp->maxy * 1.5;
 160                         hp->a = 1;
 161                         hp->b = 1.4;
 162                         hp->c = 0.3;
 163                         hp->i = hp->j = 0;
 164                         break;
 165                 case SQRT:
 166                         hp->ic = 0;
 167                         hp->jc = 0;
 168                         hp->is = 1;
 169                         hp->js = 1;
 170                         range = sqrt((double) hp->maxx * 2 * hp->maxx * 2 +
 171                                      (double) hp->maxy * 2 * hp->maxy * 2) /
 172                                 (10.0 + LRAND() % 10);
 173
 174                         hp->a = (LRAND() / MAXRAND) * range - range / 2.0;
 175                         hp->b = (LRAND() / MAXRAND) * range - range / 2.0;
 176                         hp->c = (LRAND() / MAXRAND) * range - range / 2.0;
 177                         if (!(LRAND() % 2))
 178                                 hp->c = 0.0;
 179                         hp->i = hp->j = 0.0;
 180                         break;
 181                 case STANDARD:
 182                         hp->ic = M_PI;
 183                         hp->jc = M_PI;
 184                         hp->is = hp->maxx / (M_PI * 2);
 185                         hp->js = hp->maxy / (M_PI * 2);
 186                         hp->a = 0;      /* decay */
 187                         hp->b = (LRAND() / MAXRAND) * 2.0;
 188                         hp->c = 0;
 189                         hp->i = M_PI;
 190                         hp->j = M_PI;
 191                         break;
 192                 case BIRDIE:
 193                         hp->ic = 0;
 194                         hp->jc = 0;
 195                         hp->is = hp->maxx / 2;
 196                         hp->js = hp->maxy / 2;
 197                         hp->a = 1.99 + ((LRAND() / MAXRAND) * 2.0 - 1.0) * 0.2;
 198                         hp->b = 0;
 199                         hp->c = 0.8 + ((LRAND() / MAXRAND) * 2.0 - 1.0) * 0.1;
 200                         hp->i = hp->j = 0;
 201                         break;
 202                 case TRIG:
 203                         hp->a = 5;
 204                         hp->b = 0.5 + ((LRAND() / MAXRAND) * 2.0 - 1.0) * 0.3;
 205                         hp->ic = hp->a;
 206                         hp->jc = 0;
 207                         hp->is = hp->maxx / (hp->b * 20);
 208                         hp->js = hp->maxy / (hp->b * 20);
 209                         hp->i = hp->j = 0;
 210                         break;
 211                 case CUBIC:
 212                         hp->a = 2.77;
 213                         hp->b = 0.1 + ((LRAND() / MAXRAND) * 2.0 - 1.0) * 0.1;
 214                         hp->ic = 0;
 215                         hp->jc = 0;
 216                         hp->is = hp->maxx / 4;
 217                         hp->js = hp->maxy / 4;
 218                         hp->i = hp->j = 0.1;
 219                         break;
 220                 case AILUJ:
 221                         {
 222                                 int         i;
 223                                 double      x, y, xn, yn;
 224
 225                                 hp->ic = 0;
 226                                 hp->jc = 0;
 227                                 hp->is = hp->maxx / 4;
 228                                 hp->js = hp->maxx / 4;
 229                                 do {
 230                                         hp->a = ((LRAND() / MAXRAND) * 2.0 - 1.0) * 1.5 - 0.5;
 231                                         hp->b = ((LRAND() / MAXRAND) * 2.0 - 1.0) * 1.5;
 232                                         x = y = 0;
 233 #define MAXITER 10
 234                                         for (i = 0; i < MAXITER && x * x + y * y < 13; i++) {   /* 'Brot calc */
 235                                                 xn = x * x - y * y + hp->a;
 236                                                 yn = 2 * x * y + hp->b;
 237                                                 x = xn;
 238                                                 y = yn;
 239                                         }
 240                                 } while (i < MAXITER);  /* wait for a connected set */
 241                                 hp->i = hp->j = 0.1;
 242                                 break;
 243                         }
 244         }
 245         hp->pix = 0;
 246         hp->inc = 0;
 247
 248         if (hp->pointBuffer == NULL) {
 249                 hp->pointBuffer = (XPoint *) malloc(sizeof (XPoint) * MI_COUNT(mi));
 250                 /* if fails will check later */
 251         }
 252
 253 #ifndef STANDALONE
 254         /* Clear the background. */
 255         MI_CLEARWINDOW(mi);
 256 #endif
 257
 258         XSetForeground(MI_DISPLAY(mi), MI_GC(mi), MI_WHITE_PIXEL(mi));
 259         hp->count = 0;
 260     hp->sqrt_sign = 1;
 261     hp->std_sign = 1;
 262 }
 263
 264
 265 static void
 266 draw_discrete_1 (ModeInfo * mi)
 267 {
 268         Display    *dsp = MI_DISPLAY(mi);
 269         Window      win = MI_WINDOW(mi);
 270         double      oldj, oldi;
 271         int         count = MI_COUNT(mi);
 272         int         cycles = MI_CYCLES(mi);
 273         int         k;
 274         XPoint     *xp;
 275         GC          gc = MI_GC(mi);
 276         discretestruct *hp;
 277
 278         if (discretes == NULL)
 279                 return;
 280         hp = &discretes[MI_SCREEN(mi)];
 281         if (hp->pointBuffer == NULL)
 282                 return;
 283
 284         k = count;
 285         xp = hp->pointBuffer;
 286
 287         hp->inc++;
 288
 289         MI_IS_DRAWN(mi) = True;
 290
 291         if (MI_NPIXELS(mi) > 2) {
 292                 XSetForeground(dsp, gc, MI_PIXEL(mi, hp->pix));
 293                 if (++hp->pix >= MI_NPIXELS(mi))
 294                         hp->pix = 0;
 295         }
 296         while (k--) {
 297                 oldj = hp->j;
 298                 oldi = hp->i;
 299                 switch (hp->op) {
 300                         case HSHOE:
 301                                 {
 302                                         int         i;
 303
 304 #if 0
 305                                         if (!k) {
 306                                                 XSetForeground(dsp, gc, MI_BLACK_PIXEL(mi));
 307                                                 XFillRectangle(dsp, win, gc, 0, 0, hp->maxx, hp->maxy);
 308                                                 XSetForeground(dsp, gc, MI_PIXEL(mi, hp->pix));
 309                                         } else
 310 #endif
 311 #define HD
 312 #ifdef HD
 313                                         if (k < count / 4) {
 314                                                 hp->i = ((double) k / count) * 8 - 1;
 315                                                 hp->j = 1;
 316                                         } else if (k < count / 2) {
 317                                                 hp->i = 1;
 318                                                 hp->j = 3 - ((double) k / count) * 8;
 319                                         } else if (k < 3 * count / 4) {
 320                                                 hp->i = 5 - ((double) k / count) * 8;
 321                                                 hp->j = -1;
 322                                         } else {
 323                                                 hp->i = -1;
 324                                                 hp->j = ((double) k / count) * 8 - 7;
 325                                         }
 326                                         for (i = 1; i < (hp->inc % 15); i++) {
 327                                                 oldj = hp->j;
 328                                                 oldi = hp->i;
 329 #endif
 330                                                 hp->i = (hp->a * oldi + hp->b) * oldj;
 331                                                 hp->j = (hp->e - hp->d + hp->c * oldi) * oldj * oldj - hp->c * oldi + hp->d;
 332 #ifdef HD
 333                                         }
 334 #endif
 335                                         break;
 336                                 }
 337                         case DELOG:
 338                                 hp->j = oldi;
 339                                 hp->i = hp->a * oldi * (1 - oldj);
 340                                 break;
 341                         case HENON:
 342                                 hp->i = oldj + hp->a - hp->b * oldi * oldi;
 343                                 hp->j = hp->c * oldi;
 344                                 break;
 345                         case SQRT:
 346                                 if (k) {
 347                                         hp->j = hp->a + hp->i;
 348                                         hp->i = -oldj + (hp->i < 0
 349                                         ? sqrt(fabs(hp->b * (hp->i - hp->c)))
 350                                                          : -sqrt(fabs(hp->b * (hp->i - hp->c))));
 351                                 } else {
 352                                         hp->i = (hp->sqrt_sign ? 1 : -1) * hp->inc * hp->maxx / cycles / 2;
 353                                         hp->j = hp->a + hp->i;
 354                                         hp->sqrt_sign = !hp->sqrt_sign;
 355                                 }
 356                                 break;
 357                         case STANDARD:
 358                                 if (k) {
 359                                         hp->j = (1 - hp->a) * oldj + hp->b * sin(oldi) + hp->a * hp->c;
 360                                         hp->j = fmod(hp->j + 2 * M_PI, 2 * M_PI);
 361                                         hp->i = oldi + hp->j;
 362                                         hp->i = fmod(hp->i + 2 * M_PI, 2 * M_PI);
 363                                 } else {
 364                                         hp->j = M_PI + fmod((hp->std_sign ? 1 : -1) * hp->inc * 2 * M_PI / (cycles - 0.5), M_PI);
 365                                         hp->i = M_PI;
 366                                         hp->std_sign = !hp->std_sign;
 367                                 }
 368                                 break;
 369                         case BIRDIE:
 370                                 hp->j = oldi;
 371                                 hp->i = (1 - hp->c) * cos(M_PI * hp->a * oldj) + hp->c * hp->b;
 372                                 hp->b = oldj;
 373                                 break;
 374                         case TRIG:
 375                                 {
 376                                         double      r2 = oldi * oldi + oldj * oldj;
 377
 378                                         hp->i = hp->a + hp->b * (oldi * cos(r2) - oldj * sin(r2));
 379                                         hp->j = hp->b * (oldj * cos(r2) + oldi * sin(r2));
 380                                 }
 381                                 break;
 382                         case CUBIC:
 383                                 hp->i = oldj;
 384                                 hp->j = hp->a * oldj - oldj * oldj * oldj - hp->b * oldi;
 385                                 break;
 386                         case AILUJ:
 387                                 hp->i = ((LRAND() < MAXRAND / 2) ? -1 : 1) *
 388                                         sqrt(((oldi - hp->a) +
 389                                               sqrt((oldi - hp->a) * (oldi - hp->a) + (oldj - hp->b) * (oldj - hp->b))) / 2);
 390                                 if (hp->i < 0.00000001 && hp->i > -0.00000001)
 391                                         hp->i = (hp->i > 0.0) ? 0.00000001 : -0.00000001;
 392                                 hp->j = (oldj - hp->b) / (2 * hp->i);
 393                                 break;
 394                 }
 395                 xp->x = hp->maxx / 2 + (int) ((hp->i - hp->ic) * hp->is);
 396                 xp->y = hp->maxy / 2 - (int) ((hp->j - hp->jc) * hp->js);
 397                 xp++;
 398         }
 399         XDrawPoints(dsp, win, gc, hp->pointBuffer, count, CoordModeOrigin);
 400 }
 401
 402 ENTRYPOINT void
 403 draw_discrete (ModeInfo * mi)
 404 {
 405   discretestruct *hp = &discretes[MI_SCREEN(mi)];
 406   int cycles = MI_CYCLES(mi);
 407   int i;
 408
 409   if (hp->eraser) {
 410     hp->eraser = erase_window (MI_DISPLAY(mi), MI_WINDOW(mi), hp->eraser);
 411     return;
 412   }
 413
 414   for (i = 0; i < 10; i++) {
 415     draw_discrete_1 (mi);
 416     hp->count++;
 417   }
 418
 419   if (hp->count > cycles) {
 420     hp->eraser = erase_window (MI_DISPLAY(mi), MI_WINDOW(mi), hp->eraser);
 421     init_discrete(mi);
 422   }
 423 }
 424
 425
 426 ENTRYPOINT void
 427 reshape_discrete(ModeInfo * mi, int width, int height)
 428 {
 429   discretestruct *hp = &discretes[MI_SCREEN(mi)];
 430   hp->maxx = width;
 431   hp->maxy = height;
 432   XClearWindow (MI_DISPLAY (mi), MI_WINDOW(mi));
 433 }
 434
 435 ENTRYPOINT void
 436 release_discrete(ModeInfo * mi)
 437 {
 438         if (discretes != NULL) {
 439                 int         screen;
 440
 441                 for (screen = 0; screen < MI_NUM_SCREENS(mi); screen++) {
 442                         discretestruct *hp = &discretes[screen];
 443
 444                         if (hp->pointBuffer != NULL) {
 445                                 (void) free((void *) hp->pointBuffer);
 446                                 /* hp->pointBuffer = NULL; */
 447                         }
 448                 }
 449                 (void) free((void *) discretes);
 450                 discretes = (discretestruct *) NULL;
 451         }
 452 }
 453
 454 ENTRYPOINT void
 455 refresh_discrete(ModeInfo * mi)
 456 {
 457         MI_CLEARWINDOW(mi);
 458 }
 459
 460 XSCREENSAVER_MODULE ("Discrete", discrete)
 461
 462 #endif /* MODE_discrete */