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 release_discrete 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", (char *) NULL,
  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 static void free_discrete(ModeInfo * mi);
 114
 115 ENTRYPOINT void
 116 init_discrete (ModeInfo * mi)
 117 {
 118         double      range;
 119         discretestruct *hp;
 120
 121         MI_INIT (mi, discretes, free_discrete);
 122         hp = &discretes[MI_SCREEN(mi)];
 123
 124         hp->maxx = MI_WIDTH(mi);
 125         hp->maxy = MI_HEIGHT(mi);
 126 #ifdef TEST
 127         hp->op = TEST;
 128 #else
 129         hp->op = bias[LRAND() % BIASES];
 130 #endif
 131         switch (hp->op) {
 132                 case HSHOE:
 133                         hp->ic = 0;
 134                         hp->jc = 0;
 135                         hp->is = hp->maxx / (4);
 136                         hp->js = hp->maxy / (4);
 137                         hp->a = 0.5;
 138                         hp->b = 0.5;
 139                         hp->c = 0.2;
 140                         hp->d = -1.25;
 141                         hp->e = 1;
 142                         hp->i = hp->j = 0.0;
 143                         break;
 144                 case DELOG:
 145                         hp->ic = 0.5;
 146                         hp->jc = 0.3;
 147                         hp->is = hp->maxx / 1.5;
 148                         hp->js = hp->maxy / 1.5;
 149                         hp->a = 2.176399;
 150                         hp->i = hp->j = 0.01;
 151                         break;
 152                 case HENON:
 153                         hp->jc = ((LRAND() / MAXRAND) * 2.0 - 1.0) * 0.4;
 154                         hp->ic = 1.3 * (1 - (hp->jc * hp->jc) / (0.4 * 0.4));
 155                         hp->is = hp->maxx;
 156                         hp->js = hp->maxy * 1.5;
 157                         hp->a = 1;
 158                         hp->b = 1.4;
 159                         hp->c = 0.3;
 160                         hp->i = hp->j = 0;
 161                         break;
 162                 case SQRT:
 163                         hp->ic = 0;
 164                         hp->jc = 0;
 165                         hp->is = 1;
 166                         hp->js = 1;
 167                         range = sqrt((double) hp->maxx * 2 * hp->maxx * 2 +
 168                                      (double) hp->maxy * 2 * hp->maxy * 2) /
 169                                 (10.0 + LRAND() % 10);
 170
 171                         hp->a = (LRAND() / MAXRAND) * range - range / 2.0;
 172                         hp->b = (LRAND() / MAXRAND) * range - range / 2.0;
 173                         hp->c = (LRAND() / MAXRAND) * range - range / 2.0;
 174                         if (!(LRAND() % 2))
 175                                 hp->c = 0.0;
 176                         hp->i = hp->j = 0.0;
 177                         break;
 178                 case STANDARD:
 179                         hp->ic = M_PI;
 180                         hp->jc = M_PI;
 181                         hp->is = hp->maxx / (M_PI * 2);
 182                         hp->js = hp->maxy / (M_PI * 2);
 183                         hp->a = 0;      /* decay */
 184                         hp->b = (LRAND() / MAXRAND) * 2.0;
 185                         hp->c = 0;
 186                         hp->i = M_PI;
 187                         hp->j = M_PI;
 188                         break;
 189                 case BIRDIE:
 190                         hp->ic = 0;
 191                         hp->jc = 0;
 192                         hp->is = hp->maxx / 2;
 193                         hp->js = hp->maxy / 2;
 194                         hp->a = 1.99 + ((LRAND() / MAXRAND) * 2.0 - 1.0) * 0.2;
 195                         hp->b = 0;
 196                         hp->c = 0.8 + ((LRAND() / MAXRAND) * 2.0 - 1.0) * 0.1;
 197                         hp->i = hp->j = 0;
 198                         break;
 199                 case TRIG:
 200                         hp->a = 5;
 201                         hp->b = 0.5 + ((LRAND() / MAXRAND) * 2.0 - 1.0) * 0.3;
 202                         hp->ic = hp->a;
 203                         hp->jc = 0;
 204                         hp->is = hp->maxx / (hp->b * 20);
 205                         hp->js = hp->maxy / (hp->b * 20);
 206                         hp->i = hp->j = 0;
 207                         break;
 208                 case CUBIC:
 209                         hp->a = 2.77;
 210                         hp->b = 0.1 + ((LRAND() / MAXRAND) * 2.0 - 1.0) * 0.1;
 211                         hp->ic = 0;
 212                         hp->jc = 0;
 213                         hp->is = hp->maxx / 4;
 214                         hp->js = hp->maxy / 4;
 215                         hp->i = hp->j = 0.1;
 216                         break;
 217                 case AILUJ:
 218                         {
 219                                 int         i;
 220                                 double      x, y, xn, yn;
 221
 222                                 hp->ic = 0;
 223                                 hp->jc = 0;
 224                                 hp->is = hp->maxx / 4;
 225                                 hp->js = hp->maxx / 4;
 226                                 do {
 227                                         hp->a = ((LRAND() / MAXRAND) * 2.0 - 1.0) * 1.5 - 0.5;
 228                                         hp->b = ((LRAND() / MAXRAND) * 2.0 - 1.0) * 1.5;
 229                                         x = y = 0;
 230 #define MAXITER 10
 231                                         for (i = 0; i < MAXITER && x * x + y * y < 13; i++) {   /* 'Brot calc */
 232                                                 xn = x * x - y * y + hp->a;
 233                                                 yn = 2 * x * y + hp->b;
 234                                                 x = xn;
 235                                                 y = yn;
 236                                         }
 237                                 } while (i < MAXITER);  /* wait for a connected set */
 238                                 hp->i = hp->j = 0.1;
 239                                 break;
 240                         }
 241         }
 242         hp->pix = 0;
 243         hp->inc = 0;
 244
 245         if (hp->pointBuffer == NULL) {
 246                 hp->pointBuffer = (XPoint *) malloc(sizeof (XPoint) * MI_COUNT(mi));
 247                 /* if fails will check later */
 248         }
 249
 250 #ifndef STANDALONE
 251         /* Clear the background. */
 252         MI_CLEARWINDOW(mi);
 253 #endif
 254
 255         XSetForeground(MI_DISPLAY(mi), MI_GC(mi), MI_WHITE_PIXEL(mi));
 256         hp->count = 0;
 257     hp->sqrt_sign = 1;
 258     hp->std_sign = 1;
 259 }
 260
 261
 262 static void
 263 draw_discrete_1 (ModeInfo * mi)
 264 {
 265         Display    *dsp = MI_DISPLAY(mi);
 266         Window      win = MI_WINDOW(mi);
 267         double      oldj, oldi;
 268         int         count = MI_COUNT(mi);
 269         int         cycles = MI_CYCLES(mi);
 270         int         k;
 271         XPoint     *xp;
 272         GC          gc = MI_GC(mi);
 273         discretestruct *hp;
 274
 275         if (discretes == NULL)
 276                 return;
 277         hp = &discretes[MI_SCREEN(mi)];
 278         if (hp->pointBuffer == NULL)
 279                 return;
 280
 281         k = count;
 282         xp = hp->pointBuffer;
 283
 284         hp->inc++;
 285
 286         MI_IS_DRAWN(mi) = True;
 287
 288         if (MI_NPIXELS(mi) > 2) {
 289                 XSetForeground(dsp, gc, MI_PIXEL(mi, hp->pix));
 290                 if (++hp->pix >= MI_NPIXELS(mi))
 291                         hp->pix = 0;
 292         }
 293         while (k--) {
 294                 oldj = hp->j;
 295                 oldi = hp->i;
 296                 switch (hp->op) {
 297                         case HSHOE:
 298                                 {
 299                                         int         i;
 300
 301 #if 0
 302                                         if (!k) {
 303                                                 XSetForeground(dsp, gc, MI_BLACK_PIXEL(mi));
 304                                                 XFillRectangle(dsp, win, gc, 0, 0, hp->maxx, hp->maxy);
 305                                                 XSetForeground(dsp, gc, MI_PIXEL(mi, hp->pix));
 306                                         } else
 307 #endif
 308 #define HD
 309 #ifdef HD
 310                                         if (k < count / 4) {
 311                                                 hp->i = ((double) k / count) * 8 - 1;
 312                                                 hp->j = 1;
 313                                         } else if (k < count / 2) {
 314                                                 hp->i = 1;
 315                                                 hp->j = 3 - ((double) k / count) * 8;
 316                                         } else if (k < 3 * count / 4) {
 317                                                 hp->i = 5 - ((double) k / count) * 8;
 318                                                 hp->j = -1;
 319                                         } else {
 320                                                 hp->i = -1;
 321                                                 hp->j = ((double) k / count) * 8 - 7;
 322                                         }
 323                                         for (i = 1; i < (hp->inc % 15); i++) {
 324                                                 oldj = hp->j;
 325                                                 oldi = hp->i;
 326 #endif
 327                                                 hp->i = (hp->a * oldi + hp->b) * oldj;
 328                                                 hp->j = (hp->e - hp->d + hp->c * oldi) * oldj * oldj - hp->c * oldi + hp->d;
 329 #ifdef HD
 330                                         }
 331 #endif
 332                                         break;
 333                                 }
 334                         case DELOG:
 335                                 hp->j = oldi;
 336                                 hp->i = hp->a * oldi * (1 - oldj);
 337                                 break;
 338                         case HENON:
 339                                 hp->i = oldj + hp->a - hp->b * oldi * oldi;
 340                                 hp->j = hp->c * oldi;
 341                                 break;
 342                         case SQRT:
 343                                 if (k) {
 344                                         hp->j = hp->a + hp->i;
 345                                         hp->i = -oldj + (hp->i < 0
 346                                         ? sqrt(fabs(hp->b * (hp->i - hp->c)))
 347                                                          : -sqrt(fabs(hp->b * (hp->i - hp->c))));
 348                                 } else {
 349                                         hp->i = (hp->sqrt_sign ? 1 : -1) * hp->inc * hp->maxx / cycles / 2;
 350                                         hp->j = hp->a + hp->i;
 351                                         hp->sqrt_sign = !hp->sqrt_sign;
 352                                 }
 353                                 break;
 354                         case STANDARD:
 355                                 if (k) {
 356                                         hp->j = (1 - hp->a) * oldj + hp->b * sin(oldi) + hp->a * hp->c;
 357                                         hp->j = fmod(hp->j + 2 * M_PI, 2 * M_PI);
 358                                         hp->i = oldi + hp->j;
 359                                         hp->i = fmod(hp->i + 2 * M_PI, 2 * M_PI);
 360                                 } else {
 361                                         hp->j = M_PI + fmod((hp->std_sign ? 1 : -1) * hp->inc * 2 * M_PI / (cycles - 0.5), M_PI);
 362                                         hp->i = M_PI;
 363                                         hp->std_sign = !hp->std_sign;
 364                                 }
 365                                 break;
 366                         case BIRDIE:
 367                                 hp->j = oldi;
 368                                 hp->i = (1 - hp->c) * cos(M_PI * hp->a * oldj) + hp->c * hp->b;
 369                                 hp->b = oldj;
 370                                 break;
 371                         case TRIG:
 372                                 {
 373                                         double      r2 = oldi * oldi + oldj * oldj;
 374
 375                                         hp->i = hp->a + hp->b * (oldi * cos(r2) - oldj * sin(r2));
 376                                         hp->j = hp->b * (oldj * cos(r2) + oldi * sin(r2));
 377                                 }
 378                                 break;
 379                         case CUBIC:
 380                                 hp->i = oldj;
 381                                 hp->j = hp->a * oldj - oldj * oldj * oldj - hp->b * oldi;
 382                                 break;
 383                         case AILUJ:
 384                                 hp->i = ((LRAND() < MAXRAND / 2) ? -1 : 1) *
 385                                         sqrt(((oldi - hp->a) +
 386                                               sqrt((oldi - hp->a) * (oldi - hp->a) + (oldj - hp->b) * (oldj - hp->b))) / 2);
 387                                 if (hp->i < 0.00000001 && hp->i > -0.00000001)
 388                                         hp->i = (hp->i > 0.0) ? 0.00000001 : -0.00000001;
 389                                 hp->j = (oldj - hp->b) / (2 * hp->i);
 390                                 break;
 391                 }
 392                 xp->x = hp->maxx / 2 + (int) ((hp->i - hp->ic) * hp->is);
 393                 xp->y = hp->maxy / 2 - (int) ((hp->j - hp->jc) * hp->js);
 394                 xp++;
 395         }
 396         XDrawPoints(dsp, win, gc, hp->pointBuffer, count, CoordModeOrigin);
 397 }
 398
 399 ENTRYPOINT void
 400 draw_discrete (ModeInfo * mi)
 401 {
 402   discretestruct *hp = &discretes[MI_SCREEN(mi)];
 403   int cycles = MI_CYCLES(mi);
 404   int i;
 405
 406   if (hp->eraser) {
 407     hp->eraser = erase_window (MI_DISPLAY(mi), MI_WINDOW(mi), hp->eraser);
 408     if (!hp->eraser)
 409       init_discrete(mi);
 410     return;
 411   }
 412
 413   for (i = 0; i < 10; i++) {
 414     draw_discrete_1 (mi);
 415     hp->count++;
 416   }
 417
 418   if (hp->count > cycles) {
 419     hp->eraser = erase_window (MI_DISPLAY(mi), MI_WINDOW(mi), hp->eraser);
 420   }
 421 }
 422
 423
 424 ENTRYPOINT void
 425 reshape_discrete(ModeInfo * mi, int width, int height)
 426 {
 427   discretestruct *hp = &discretes[MI_SCREEN(mi)];
 428   hp->maxx = width;
 429   hp->maxy = height;
 430   XClearWindow (MI_DISPLAY (mi), MI_WINDOW(mi));
 431 }
 432
 433 static void
 434 free_discrete(ModeInfo * mi)
 435 {
 436         discretestruct *hp = &discretes[MI_SCREEN(mi)];
 437
 438         if (hp->pointBuffer != NULL) {
 439                 (void) free((void *) hp->pointBuffer);
 440                 /* hp->pointBuffer = NULL; */
 441         }
 442 }
 443
 444 ENTRYPOINT void
 445 refresh_discrete(ModeInfo * mi)
 446 {
 447         MI_CLEARWINDOW(mi);
 448 }
 449
 450 ENTRYPOINT Bool
 451 discrete_handle_event (ModeInfo *mi, XEvent *event)
 452 {
 453   discretestruct *hp = &discretes[MI_SCREEN(mi)];
 454   if (screenhack_event_helper (MI_DISPLAY(mi), MI_WINDOW(mi), event))
 455     {
 456       hp->count = MI_CYCLES(mi);
 457       return True;
 458     }
 459   return False;
 460 }
 461
 462
 463
 464 XSCREENSAVER_MODULE ("Discrete", discrete)
 465
 466 #endif /* MODE_discrete */