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

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