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: 1000 \n" \
  37                                         "*count: 4096 \n" \
  38                                         "*cycles: 2500 \n" \
  39                                         "*ncolors: 100 \n"
  40 # define SMOOTH_COLORS
  41 # define reshape_discrete 0
  42 # define discrete_handle_event 0
  43 # include "xlockmore.h"         /* in xscreensaver distribution */
  44 # include "erase.h"
  45 #else /* STANDALONE */
  46 # include "xlock.h"             /* in xlockmore distribution */
  47 #endif /* STANDALONE */
  48
  49 #ifdef MODE_discrete
  50
  51 ENTRYPOINT ModeSpecOpt discrete_opts =
  52 {0, (XrmOptionDescRec *) NULL, 0, (argtype *) NULL, (OptionStruct *) NULL};
  53
  54 #ifdef USE_MODULES
  55 ModStruct   discrete_description =
  56 {"discrete", "init_discrete", "draw_discrete", "release_discrete",
  57  "refresh_discrete", "init_discrete", (char *) NULL, &discrete_opts,
  58  1000, 4096, 2500, 1, 64, 1.0, "",
  59  "Shows various discrete maps", 0, NULL};
  60
  61 #endif
  62
  63 enum ftypes {
  64         SQRT, BIRDIE, STANDARD, TRIG, CUBIC, HENON, AILUJ, HSHOE, DELOG
  65 };
  66
  67 /*#define TEST STANDARD */
  68
  69 #define BIASES 18
  70 static enum ftypes bias[BIASES] =
  71 {
  72         STANDARD, STANDARD, STANDARD, STANDARD,
  73         SQRT, SQRT, SQRT, SQRT,
  74         BIRDIE, BIRDIE, BIRDIE,
  75         AILUJ, AILUJ, AILUJ,
  76         TRIG, TRIG,
  77         CUBIC,
  78         HENON,
  79 };
  80
  81 typedef struct {
  82         int         maxx;
  83         int         maxy;       /* max of the screen */
  84         double      a;
  85         double      b;
  86         double      c;
  87         double      d;
  88         double      e;
  89         double      i;
  90         double      j;          /* discrete parameters */
  91         double      ic;
  92         double      jc;
  93         double      is;
  94         double      js;
  95         int         inc;
  96         int         pix;
  97         enum ftypes op;
  98         int         count;
  99         XPoint     *pointBuffer;        /* pointer for XDrawPoints */
 100
 101     int sqrt_sign, std_sign;
 102
 103 #ifdef STANDALONE
 104   eraser_state *eraser;
 105 #endif
 106
 107 } discretestruct;
 108
 109 static discretestruct *discretes = (discretestruct *) NULL;
 110
 111 ENTRYPOINT void
 112 init_discrete (ModeInfo * mi)
 113 {
 114         double      range;
 115         discretestruct *hp;
 116
 117         if (discretes == NULL) {
 118                 if ((discretes =
 119                      (discretestruct *) calloc(MI_NUM_SCREENS(mi),
 120                                            sizeof (discretestruct))) == NULL)
 121                         return;
 122         }
 123         hp = &discretes[MI_SCREEN(mi)];
 124
 125         hp->maxx = MI_WIDTH(mi);
 126         hp->maxy = MI_HEIGHT(mi);
 127 #ifdef TEST
 128         hp->op = TEST;
 129 #else
 130         hp->op = bias[LRAND() % BIASES];
 131 #endif
 132         switch (hp->op) {
 133                 case HSHOE:
 134                         hp->ic = 0;
 135                         hp->jc = 0;
 136                         hp->is = hp->maxx / (4);
 137                         hp->js = hp->maxy / (4);
 138                         hp->a = 0.5;
 139                         hp->b = 0.5;
 140                         hp->c = 0.2;
 141                         hp->d = -1.25;
 142                         hp->e = 1;
 143                         hp->i = hp->j = 0.0;
 144                         break;
 145                 case DELOG:
 146                         hp->ic = 0.5;
 147                         hp->jc = 0.3;
 148                         hp->is = hp->maxx / 1.5;
 149                         hp->js = hp->maxy / 1.5;
 150                         hp->a = 2.176399;
 151                         hp->i = hp->j = 0.01;
 152                         break;
 153                 case HENON:
 154                         hp->jc = ((LRAND() / MAXRAND) * 2.0 - 1.0) * 0.4;
 155                         hp->ic = 1.3 * (1 - (hp->jc * hp->jc) / (0.4 * 0.4));
 156                         hp->is = hp->maxx;
 157                         hp->js = hp->maxy * 1.5;
 158                         hp->a = 1;
 159                         hp->b = 1.4;
 160                         hp->c = 0.3;
 161                         hp->i = hp->j = 0;
 162                         break;
 163                 case SQRT:
 164                         hp->ic = 0;
 165                         hp->jc = 0;
 166                         hp->is = 1;
 167                         hp->js = 1;
 168                         range = sqrt((double) hp->maxx * 2 * hp->maxx * 2 +
 169                                      (double) hp->maxy * 2 * hp->maxy * 2) /
 170                                 (10.0 + LRAND() % 10);
 171
 172                         hp->a = (LRAND() / MAXRAND) * range - range / 2.0;
 173                         hp->b = (LRAND() / MAXRAND) * range - range / 2.0;
 174                         hp->c = (LRAND() / MAXRAND) * range - range / 2.0;
 175                         if (!(LRAND() % 2))
 176                                 hp->c = 0.0;
 177                         hp->i = hp->j = 0.0;
 178                         break;
 179                 case STANDARD:
 180                         hp->ic = M_PI;
 181                         hp->jc = M_PI;
 182                         hp->is = hp->maxx / (M_PI * 2);
 183                         hp->js = hp->maxy / (M_PI * 2);
 184                         hp->a = 0;      /* decay */
 185                         hp->b = (LRAND() / MAXRAND) * 2.0;
 186                         hp->c = 0;
 187                         hp->i = M_PI;
 188                         hp->j = M_PI;
 189                         break;
 190                 case BIRDIE:
 191                         hp->ic = 0;
 192                         hp->jc = 0;
 193                         hp->is = hp->maxx / 2;
 194                         hp->js = hp->maxy / 2;
 195                         hp->a = 1.99 + ((LRAND() / MAXRAND) * 2.0 - 1.0) * 0.2;
 196                         hp->b = 0;
 197                         hp->c = 0.8 + ((LRAND() / MAXRAND) * 2.0 - 1.0) * 0.1;
 198                         hp->i = hp->j = 0;
 199                         break;
 200                 case TRIG:
 201                         hp->a = 5;
 202                         hp->b = 0.5 + ((LRAND() / MAXRAND) * 2.0 - 1.0) * 0.3;
 203                         hp->ic = hp->a;
 204                         hp->jc = 0;
 205                         hp->is = hp->maxx / (hp->b * 20);
 206                         hp->js = hp->maxy / (hp->b * 20);
 207                         hp->i = hp->j = 0;
 208                         break;
 209                 case CUBIC:
 210                         hp->a = 2.77;
 211                         hp->b = 0.1 + ((LRAND() / MAXRAND) * 2.0 - 1.0) * 0.1;
 212                         hp->ic = 0;
 213                         hp->jc = 0;
 214                         hp->is = hp->maxx / 4;
 215                         hp->js = hp->maxy / 4;
 216                         hp->i = hp->j = 0.1;
 217                         break;
 218                 case AILUJ:
 219                         {
 220                                 int         i;
 221                                 double      x, y, xn, yn;
 222
 223                                 hp->ic = 0;
 224                                 hp->jc = 0;
 225                                 hp->is = hp->maxx / 4;
 226                                 hp->js = hp->maxx / 4;
 227                                 do {
 228                                         hp->a = ((LRAND() / MAXRAND) * 2.0 - 1.0) * 1.5 - 0.5;
 229                                         hp->b = ((LRAND() / MAXRAND) * 2.0 - 1.0) * 1.5;
 230                                         x = y = 0;
 231 #define MAXITER 10
 232                                         for (i = 0; i < MAXITER && x * x + y * y < 13; i++) {   /* 'Brot calc */
 233                                                 xn = x * x - y * y + hp->a;
 234                                                 yn = 2 * x * y + hp->b;
 235                                                 x = xn;
 236                                                 y = yn;
 237                                         }
 238                                 } while (i < MAXITER);  /* wait for a connected set */
 239                                 hp->i = hp->j = 0.1;
 240                                 break;
 241                         }
 242         }
 243         hp->pix = 0;
 244         hp->inc = 0;
 245
 246         if (hp->pointBuffer == NULL) {
 247                 hp->pointBuffer = (XPoint *) malloc(sizeof (XPoint) * MI_COUNT(mi));
 248                 /* if fails will check later */
 249         }
 250
 251 #ifndef STANDALONE
 252         /* Clear the background. */
 253         MI_CLEARWINDOW(mi);
 254 #endif
 255
 256         XSetForeground(MI_DISPLAY(mi), MI_GC(mi), MI_WHITE_PIXEL(mi));
 257         hp->count = 0;
 258     hp->sqrt_sign = 1;
 259     hp->std_sign = 1;
 260 }
 261
 262
 263 ENTRYPOINT void
 264 draw_discrete (ModeInfo * mi)
 265 {
 266         Display    *dsp = MI_DISPLAY(mi);
 267         Window      win = MI_WINDOW(mi);
 268         double      oldj, oldi;
 269         int         count = MI_COUNT(mi);
 270         int         cycles = MI_CYCLES(mi);
 271         int         k;
 272         XPoint     *xp;
 273         GC          gc = MI_GC(mi);
 274         discretestruct *hp;
 275
 276         if (discretes == NULL)
 277                 return;
 278         hp = &discretes[MI_SCREEN(mi)];
 279         if (hp->pointBuffer == NULL)
 280                 return;
 281
 282     if (hp->eraser) {
 283       hp->eraser = erase_window (MI_DISPLAY(mi), MI_WINDOW(mi), hp->eraser);
 284       return;
 285     }
 286
 287         k = count;
 288         xp = hp->pointBuffer;
 289
 290         hp->inc++;
 291
 292         MI_IS_DRAWN(mi) = True;
 293
 294         if (MI_NPIXELS(mi) > 2) {
 295                 XSetForeground(dsp, gc, MI_PIXEL(mi, hp->pix));
 296                 if (++hp->pix >= MI_NPIXELS(mi))
 297                         hp->pix = 0;
 298         }
 299         while (k--) {
 300                 oldj = hp->j;
 301                 oldi = hp->i;
 302                 switch (hp->op) {
 303                         case HSHOE:
 304                                 {
 305                                         int         i;
 306
 307 #if 0
 308                                         if (!k) {
 309                                                 XSetForeground(dsp, gc, MI_BLACK_PIXEL(mi));
 310                                                 XFillRectangle(dsp, win, gc, 0, 0, hp->maxx, hp->maxy);
 311                                                 XSetForeground(dsp, gc, MI_PIXEL(mi, hp->pix));
 312                                         } else
 313 #endif
 314 #define HD
 315 #ifdef HD
 316                                         if (k < count / 4) {
 317                                                 hp->i = ((double) k / count) * 8 - 1;
 318                                                 hp->j = 1;
 319                                         } else if (k < count / 2) {
 320                                                 hp->i = 1;
 321                                                 hp->j = 3 - ((double) k / count) * 8;
 322                                         } else if (k < 3 * count / 4) {
 323                                                 hp->i = 5 - ((double) k / count) * 8;
 324                                                 hp->j = -1;
 325                                         } else {
 326                                                 hp->i = -1;
 327                                                 hp->j = ((double) k / count) * 8 - 7;
 328                                         }
 329                                         for (i = 1; i < (hp->inc % 15); i++) {
 330                                                 oldj = hp->j;
 331                                                 oldi = hp->i;
 332 #endif
 333                                                 hp->i = (hp->a * oldi + hp->b) * oldj;
 334                                                 hp->j = (hp->e - hp->d + hp->c * oldi) * oldj * oldj - hp->c * oldi + hp->d;
 335 #ifdef HD
 336                                         }
 337 #endif
 338                                         break;
 339                                 }
 340                         case DELOG:
 341                                 hp->j = oldi;
 342                                 hp->i = hp->a * oldi * (1 - oldj);
 343                                 break;
 344                         case HENON:
 345                                 hp->i = oldj + hp->a - hp->b * oldi * oldi;
 346                                 hp->j = hp->c * oldi;
 347                                 break;
 348                         case SQRT:
 349                                 if (k) {
 350                                         hp->j = hp->a + hp->i;
 351                                         hp->i = -oldj + (hp->i < 0
 352                                         ? sqrt(fabs(hp->b * (hp->i - hp->c)))
 353                                                          : -sqrt(fabs(hp->b * (hp->i - hp->c))));
 354                                 } else {
 355                                         hp->i = (hp->sqrt_sign ? 1 : -1) * hp->inc * hp->maxx / cycles / 2;
 356                                         hp->j = hp->a + hp->i;
 357                                         hp->sqrt_sign = !hp->sqrt_sign;
 358                                 }
 359                                 break;
 360                         case STANDARD:
 361                                 if (k) {
 362                                         hp->j = (1 - hp->a) * oldj + hp->b * sin(oldi) + hp->a * hp->c;
 363                                         hp->j = fmod(hp->j + 2 * M_PI, 2 * M_PI);
 364                                         hp->i = oldi + hp->j;
 365                                         hp->i = fmod(hp->i + 2 * M_PI, 2 * M_PI);
 366                                 } else {
 367                                         hp->j = M_PI + fmod((hp->std_sign ? 1 : -1) * hp->inc * 2 * M_PI / (cycles - 0.5), M_PI);
 368                                         hp->i = M_PI;
 369                                         hp->std_sign = !hp->std_sign;
 370                                 }
 371                                 break;
 372                         case BIRDIE:
 373                                 hp->j = oldi;
 374                                 hp->i = (1 - hp->c) * cos(M_PI * hp->a * oldj) + hp->c * hp->b;
 375                                 hp->b = oldj;
 376                                 break;
 377                         case TRIG:
 378                                 {
 379                                         double      r2 = oldi * oldi + oldj * oldj;
 380
 381                                         hp->i = hp->a + hp->b * (oldi * cos(r2) - oldj * sin(r2));
 382                                         hp->j = hp->b * (oldj * cos(r2) + oldi * sin(r2));
 383                                 }
 384                                 break;
 385                         case CUBIC:
 386                                 hp->i = oldj;
 387                                 hp->j = hp->a * oldj - oldj * oldj * oldj - hp->b * oldi;
 388                                 break;
 389                         case AILUJ:
 390                                 hp->i = ((LRAND() < MAXRAND / 2) ? -1 : 1) *
 391                                         sqrt(((oldi - hp->a) +
 392                                               sqrt((oldi - hp->a) * (oldi - hp->a) + (oldj - hp->b) * (oldj - hp->b))) / 2);
 393                                 if (hp->i < 0.00000001 && hp->i > -0.00000001)
 394                                         hp->i = (hp->i > 0.0) ? 0.00000001 : -0.00000001;
 395                                 hp->j = (oldj - hp->b) / (2 * hp->i);
 396                                 break;
 397                 }
 398                 xp->x = hp->maxx / 2 + (int) ((hp->i - hp->ic) * hp->is);
 399                 xp->y = hp->maxy / 2 - (int) ((hp->j - hp->jc) * hp->js);
 400                 xp++;
 401         }
 402         XDrawPoints(dsp, win, gc, hp->pointBuffer, count, CoordModeOrigin);
 403         if (++hp->count > cycles) {
 404 #ifdef STANDALONE
 405       hp->eraser = erase_window (MI_DISPLAY(mi), MI_WINDOW(mi), hp->eraser);
 406 #endif /* STANDALONE */
 407                 init_discrete(mi);
 408         }
 409 }
 410
 411 ENTRYPOINT void
 412 release_discrete(ModeInfo * mi)
 413 {
 414         if (discretes != NULL) {
 415                 int         screen;
 416
 417                 for (screen = 0; screen < MI_NUM_SCREENS(mi); screen++) {
 418                         discretestruct *hp = &discretes[screen];
 419
 420                         if (hp->pointBuffer != NULL) {
 421                                 (void) free((void *) hp->pointBuffer);
 422                                 /* hp->pointBuffer = NULL; */
 423                         }
 424                 }
 425                 (void) free((void *) discretes);
 426                 discretes = (discretestruct *) NULL;
 427         }
 428 }
 429
 430 ENTRYPOINT void
 431 refresh_discrete(ModeInfo * mi)
 432 {
 433         MI_CLEARWINDOW(mi);
 434 }
 435
 436 XSCREENSAVER_MODULE ("Discrete", discrete)
 437
 438 #endif /* MODE_discrete */