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

   1 /* -*- Mode: C; tab-width: 4 -*-
   2  * julia --- continuously varying Julia set.
   3  */
   4 #if 0
   5 static const char sccsid[] = "@(#)julia.c       4.03 97/04/10 xlockmore";
   6 #endif
   7
   8 /* Copyright (c) 1995 Sean McCullough <bankshot@mailhost.nmt.edu>.
   9  *
  10  * Permission to use, copy, modify, and distribute this software and its
  11  * documentation for any purpose and without fee is hereby granted,
  12  * provided that the above copyright notice appear in all copies and that
  13  * both that copyright notice and this permission notice appear in
  14  * supporting documentation.
  15  *
  16  * This file is provided AS IS with no warranties of any kind.  The author
  17  * shall have no liability with respect to the infringement of copyrights,
  18  * trade secrets or any patents by this file or any part thereof.  In no
  19  * event will the author be liable for any lost revenue or profits or
  20  * other special, indirect and consequential damages.
  21  *
  22  * Revision History:
  23  * 10-Jun-06: j.grahl@ucl.ac.uk: tweaked functions for parameter of Julia set
  24  * 28-May-97: jwz@jwz.org: added interactive frobbing with the mouse.
  25  * 10-May-97: jwz@jwz.org: turned into a standalone program.
  26  * 02-Dec-95: snagged boilerplate from hop.c
  27  *           used ifs {w0 = sqrt(x-c), w1 = -sqrt(x-c)} with random iteration
  28  *           to plot the julia set, and sinusoidially varied parameter for set
  29  *           and plotted parameter with a circle.
  30  */
  31
  32 /*-
  33  * One thing to note is that batchcount is the *depth* of the search tree,
  34  * so the number of points computed is 2^batchcount - 1.  I use 8 or 9
  35  * on a dx266 and it looks okay.  The sinusoidal variation of the parameter
  36  * might not be as interesting as it could, but it still gives an idea of
  37  * the effect of the parameter.
  38  */
  39
  40 #ifdef STANDALONE
  41 # define DEFAULTS       "*count:                1000  \n"                       \
  42                                         "*cycles:               20    \n"                       \
  43                                         "*delay:                10000 \n"                       \
  44                                         "*ncolors:              200   \n" \
  45                                         "*fpsSolid:             true   \n" \
  46
  47 # define UNIFORM_COLORS
  48 # define reshape_julia 0
  49 # define julia_handle_event 0
  50 # include "xlockmore.h"                         /* in xscreensaver distribution */
  51 #else  /* !STANDALONE */
  52 # include "xlock.h"                                     /* in xlockmore distribution */
  53 #endif /* !STANDALONE */
  54
  55
  56 static Bool track_p;
  57
  58 #define DEF_MOUSE "False"
  59
  60 static XrmOptionDescRec opts[] =
  61 {
  62         {"-mouse", ".julia.mouse", XrmoptionNoArg, "on"},
  63         {"+mouse", ".julia.mouse", XrmoptionNoArg, "off"},
  64 };
  65 static argtype vars[] =
  66 {
  67         {&track_p, "mouse", "Mouse", DEF_MOUSE, t_Bool},
  68 };
  69 static OptionStruct desc[] =
  70 {
  71         {"-/+mouse", "turn on/off mouse tracking"},
  72 };
  73
  74 ENTRYPOINT ModeSpecOpt julia_opts = { 2, opts, 1, vars, desc };
  75
  76
  77 #define numpoints ((0x2<<jp->depth)-1)
  78
  79 typedef struct {
  80         int         centerx;
  81         int         centery;    /* center of the screen */
  82         double      cr;
  83         double      ci;         /* julia params */
  84         int         depth;
  85         int         inc;
  86         int         circsize;
  87         int         erase;
  88         int         pix;
  89         long        itree;
  90         int         buffer;
  91         int         nbuffers;
  92         int         redrawing, redrawpos;
  93         Pixmap      pixmap;
  94 #ifndef HAVE_COCOA
  95         Cursor      cursor;
  96 #endif
  97         GC          stippledGC;
  98         XPoint    **pointBuffer;        /* pointer for XDrawPoints */
  99
 100 } juliastruct;
 101
 102 static juliastruct *julias = NULL;
 103
 104 /* How many segments to draw per cycle when redrawing */
 105 #define REDRAWSTEP 3
 106
 107 static void
 108 apply(juliastruct * jp, register double xr, register double xi, int d)
 109 {
 110         double      theta, r;
 111
 112         jp->pointBuffer[jp->buffer][jp->itree].x =
 113                 (int) (0.5 * xr * jp->centerx + jp->centerx);
 114         jp->pointBuffer[jp->buffer][jp->itree].y =
 115                 (int) (0.5 * xi * jp->centery + jp->centery);
 116         jp->itree++;
 117
 118         if (d > 0) {
 119                 xi -= jp->ci;
 120                 xr -= jp->cr;
 121
 122 /* Avoid atan2: DOMAIN error message */
 123                 if (xi == 0.0 && xr == 0.0)
 124                         theta = 0.0;
 125                 else
 126                         theta = atan2(xi, xr) / 2.0;
 127
 128                 /*r = pow(xi * xi + xr * xr, 0.25); */
 129                 r = sqrt(sqrt(xi * xi + xr * xr));      /* 3 times faster */
 130
 131                 xr = r * cos(theta);
 132                 xi = r * sin(theta);
 133
 134                 d--;
 135                 apply(jp, xr, xi, d);
 136                 apply(jp, -xr, -xi, d);
 137         }
 138 }
 139
 140 static void
 141 incr(ModeInfo * mi, juliastruct * jp)
 142 {
 143         int cx, cy;
 144
 145         if (track_p)
 146           {
 147                 Window r, c;
 148                 int rx, ry;
 149                 unsigned int m;
 150                 XQueryPointer(MI_DISPLAY(mi), MI_WINDOW(mi),
 151                                           &r, &c, &rx, &ry, &cx, &cy, &m);
 152                 if (cx <= 0 || cy <= 0 ||
 153                         cx >= MI_WIN_WIDTH(mi) || cy >= MI_WIN_HEIGHT(mi))
 154                   goto NOTRACK;
 155           }
 156
 157         if (track_p)
 158           {
 159                 jp->cr = ((double) (cx + 2 - jp->centerx)) * 2 / jp->centerx;
 160                 jp->ci = ((double) (cy + 2 - jp->centery)) * 2 / jp->centery;
 161           }
 162         else
 163           {
 164           NOTRACK:
 165 #if 0
 166                 jp->cr = 1.5 * (sin(M_PI * (jp->inc / 300.0)) *
 167                                                 sin(jp->inc * M_PI / 200.0));
 168                 jp->ci = 1.5 * (cos(M_PI * (jp->inc / 300.0)) *
 169                                                 cos(jp->inc * M_PI / 200.0));
 170
 171                 jp->cr += 0.5 * cos(M_PI * jp->inc / 400.0);
 172                 jp->ci += 0.5 * sin(M_PI * jp->inc / 400.0);
 173 #else
 174         jp->cr = 1.5 * (sin(M_PI * (jp->inc / 290.0)) *
 175                         sin(jp->inc * M_PI / 210.0));
 176         jp->ci = 1.5 * (cos(M_PI * (jp->inc / 310.0)) *
 177                         cos(jp->inc * M_PI / 190.0));
 178
 179         jp->cr += 0.5 * cos(M_PI * jp->inc / 395.0);
 180         jp->ci += 0.5 * sin(M_PI * jp->inc / 410.0);
 181 #endif
 182           }
 183 }
 184
 185 ENTRYPOINT void
 186 init_julia(ModeInfo * mi)
 187 {
 188         Display    *display = MI_DISPLAY(mi);
 189         Window      window = MI_WINDOW(mi);
 190         juliastruct *jp;
 191         XGCValues   gcv;
 192         int         i;
 193
 194         if (julias == NULL) {
 195                 if ((julias = (juliastruct *) calloc(MI_NUM_SCREENS(mi),
 196                                               sizeof (juliastruct))) == NULL)
 197                         return;
 198         }
 199         jp = &julias[MI_SCREEN(mi)];
 200
 201         jp->centerx = MI_WIN_WIDTH(mi) / 2;
 202         jp->centery = MI_WIN_HEIGHT(mi) / 2;
 203
 204         jp->depth = MI_BATCHCOUNT(mi);
 205         if (jp->depth > 10)
 206                 jp->depth = 10;
 207
 208
 209 #ifndef HAVE_COCOA
 210         if (track_p && !jp->cursor)
 211           {
 212                 Pixmap bit;
 213                 XColor black;
 214                 black.red = black.green = black.blue = 0;
 215                 black.flags = DoRed|DoGreen|DoBlue;
 216                 bit = XCreatePixmapFromBitmapData (display, window, "\000", 1, 1,
 217                                                                                    MI_WIN_BLACK_PIXEL(mi),
 218                                                                                    MI_WIN_BLACK_PIXEL(mi), 1);
 219                 jp->cursor = XCreatePixmapCursor (display, bit, bit, &black, &black,
 220                                                                                   0, 0);
 221                 XFreePixmap (display, bit);
 222           }
 223 #endif /* HAVE_COCOA */
 224
 225         if (jp->pixmap != None &&
 226             jp->circsize != (MIN(jp->centerx, jp->centery) / 60) * 2 + 1) {
 227                 XFreePixmap(display, jp->pixmap);
 228                 jp->pixmap = None;
 229         }
 230         if (jp->pixmap == None) {
 231                 GC          fg_gc = None, bg_gc = None;
 232
 233                 jp->circsize = (MIN(jp->centerx, jp->centery) / 96) * 2 + 1;
 234                 jp->pixmap = XCreatePixmap(display, window, jp->circsize, jp->circsize, 1);
 235                 gcv.foreground = 1;
 236                 fg_gc = XCreateGC(display, jp->pixmap, GCForeground, &gcv);
 237                 gcv.foreground = 0;
 238                 bg_gc = XCreateGC(display, jp->pixmap, GCForeground, &gcv);
 239                 XFillRectangle(display, jp->pixmap, bg_gc,
 240                                0, 0, jp->circsize, jp->circsize);
 241                 if (jp->circsize < 2)
 242                         XDrawPoint(display, jp->pixmap, fg_gc, 0, 0);
 243                 else
 244                         XFillArc(display, jp->pixmap, fg_gc,
 245                                  0, 0, jp->circsize, jp->circsize, 0, 23040);
 246                 if (fg_gc != None)
 247                         XFreeGC(display, fg_gc);
 248                 if (bg_gc != None)
 249                         XFreeGC(display, bg_gc);
 250         }
 251
 252 #ifndef HAVE_COCOA
 253         if (MI_WIN_IS_INROOT(mi))
 254           ;
 255         else if (jp->circsize > 0)
 256           XDefineCursor (display, window, jp->cursor);
 257         else
 258           XUndefineCursor (display, window);
 259 #endif /* HAVE_COCOA */
 260
 261         if (!jp->stippledGC) {
 262                 gcv.foreground = MI_WIN_BLACK_PIXEL(mi);
 263                 gcv.background = MI_WIN_BLACK_PIXEL(mi);
 264                 if ((jp->stippledGC = XCreateGC(display, window,
 265                                  GCForeground | GCBackground, &gcv)) == None)
 266                         return;
 267         }
 268         if (MI_NPIXELS(mi) > 2)
 269                 jp->pix = NRAND(MI_NPIXELS(mi));
 270         jp->inc = ((LRAND() & 1) * 2 - 1) * NRAND(200);
 271         jp->nbuffers = (MI_CYCLES(mi) + 1);
 272         if (!jp->pointBuffer)
 273                 jp->pointBuffer = (XPoint **) calloc(jp->nbuffers, sizeof (XPoint *));
 274         for (i = 0; i < jp->nbuffers; ++i)
 275                 if (jp->pointBuffer[i])
 276                         (void) memset((char *) jp->pointBuffer[i], 0,
 277                                       numpoints * sizeof (XPoint));
 278                 else
 279                         jp->pointBuffer[i] = (XPoint *) calloc(numpoints, sizeof (XPoint));
 280         jp->buffer = 0;
 281         jp->redrawing = 0;
 282         jp->erase = 0;
 283         XClearWindow(display, window);
 284 }
 285
 286
 287 /* hack: moved here by jwz. */
 288 #define ERASE_IMAGE(d,w,g,x,y,xl,yl,xs,ys) \
 289 if (yl<y) \
 290 (y<yl+ys)?XFillRectangle(d,w,g,xl,yl,xs,y-yl): \
 291 XFillRectangle(d,w,g,xl,yl,xs,ys); \
 292 else if (yl>y) \
 293 (y>yl-ys)?XFillRectangle(d,w,g,xl,y+ys,xs,yl-y): \
 294 XFillRectangle(d,w,g,xl,yl,xs,ys); \
 295 if (xl<x) \
 296 (x<xl+xs)?XFillRectangle(d,w,g,xl,yl,x-xl,ys): \
 297 XFillRectangle(d,w,g,xl,yl,xs,ys); \
 298 else if (xl>x) \
 299 (x>xl-xs)?XFillRectangle(d,w,g,x+xs,yl,xl-x,ys): \
 300 XFillRectangle(d,w,g,xl,yl,xs,ys)
 301
 302
 303 ENTRYPOINT void
 304 draw_julia (ModeInfo * mi)
 305 {
 306         Display    *display = MI_DISPLAY(mi);
 307         Window      window = MI_WINDOW(mi);
 308         GC          gc = MI_GC(mi);
 309         juliastruct *jp = &julias[MI_SCREEN(mi)];
 310         double      r, theta;
 311         register double xr = 0.0, xi = 0.0;
 312         int         k = 64, rnd = 0, i, j;
 313         XPoint     *xp = jp->pointBuffer[jp->buffer], old_circle, new_circle;
 314
 315         old_circle.x = (int) (jp->centerx * jp->cr / 2) + jp->centerx - 2;
 316         old_circle.y = (int) (jp->centery * jp->ci / 2) + jp->centery - 2;
 317         incr(mi, jp);
 318         new_circle.x = (int) (jp->centerx * jp->cr / 2) + jp->centerx - 2;
 319         new_circle.y = (int) (jp->centery * jp->ci / 2) + jp->centery - 2;
 320         XSetForeground(display, gc, MI_WIN_BLACK_PIXEL(mi));
 321         ERASE_IMAGE(display, window, gc, new_circle.x, new_circle.y,
 322                     old_circle.x, old_circle.y, jp->circsize, jp->circsize);
 323         /* draw a circle at the c-parameter so you can see it's effect on the
 324            structure of the julia set */
 325         XSetForeground(display, jp->stippledGC, MI_WIN_WHITE_PIXEL(mi));
 326 #ifndef HAVE_COCOA
 327         XSetTSOrigin(display, jp->stippledGC, new_circle.x, new_circle.y);
 328         XSetStipple(display, jp->stippledGC, jp->pixmap);
 329         XSetFillStyle(display, jp->stippledGC, FillOpaqueStippled);
 330 #endif /* HAVE_COCOA */
 331         XFillRectangle(display, window, jp->stippledGC, new_circle.x, new_circle.y,
 332                        jp->circsize, jp->circsize);
 333         if (jp->erase == 1) {
 334                 XDrawPoints(display, window, gc,
 335                     jp->pointBuffer[jp->buffer], numpoints, CoordModeOrigin);
 336         }
 337         jp->inc++;
 338         if (MI_NPIXELS(mi) > 2) {
 339                 XSetForeground(display, gc, MI_PIXEL(mi, jp->pix));
 340                 if (++jp->pix >= MI_NPIXELS(mi))
 341                         jp->pix = 0;
 342         } else
 343                 XSetForeground(display, gc, MI_WIN_WHITE_PIXEL(mi));
 344         while (k--) {
 345
 346                 /* save calls to LRAND by using bit shifts over and over on the same
 347                    int for 32 iterations, then get a new random int */
 348                 if (!(k % 32))
 349                         rnd = LRAND();
 350
 351                 /* complex sqrt: x^0.5 = radius^0.5*(cos(theta/2) + i*sin(theta/2)) */
 352
 353                 xi -= jp->ci;
 354                 xr -= jp->cr;
 355
 356                 /* Avoid atan2: DOMAIN error message */
 357                 if (xi == 0.0 && xr == 0.0)
 358                         theta = 0.0;
 359                 else
 360                         theta = atan2(xi, xr) / 2.0;
 361
 362                 /*r = pow(xi * xi + xr * xr, 0.25); */
 363                 r = sqrt(sqrt(xi * xi + xr * xr));      /* 3 times faster */
 364
 365                 xr = r * cos(theta);
 366                 xi = r * sin(theta);
 367
 368                 if ((rnd >> (k % 32)) & 0x1) {
 369                         xi = -xi;
 370                         xr = -xr;
 371                 }
 372                 xp->x = jp->centerx + (int) ((jp->centerx >> 1) * xr);
 373                 xp->y = jp->centery + (int) ((jp->centery >> 1) * xi);
 374                 xp++;
 375         }
 376
 377         jp->itree = 0;
 378         apply(jp, xr, xi, jp->depth);
 379
 380         XDrawPoints(display, window, gc,
 381                     jp->pointBuffer[jp->buffer], numpoints, CoordModeOrigin);
 382
 383         jp->buffer++;
 384         if (jp->buffer > jp->nbuffers - 1) {
 385                 jp->buffer -= jp->nbuffers;
 386                 jp->erase = 1;
 387         }
 388         if (jp->redrawing) {
 389                 for (i = 0; i < REDRAWSTEP; i++) {
 390                         j = (jp->buffer - jp->redrawpos + jp->nbuffers) % jp->nbuffers;
 391                         XDrawPoints(display, window, gc,
 392                              jp->pointBuffer[j], numpoints, CoordModeOrigin);
 393
 394                         if (++(jp->redrawpos) >= jp->nbuffers) {
 395                                 jp->redrawing = 0;
 396                                 break;
 397                         }
 398                 }
 399         }
 400 }
 401
 402 ENTRYPOINT void
 403 release_julia (ModeInfo * mi)
 404 {
 405         if (julias != NULL) {
 406                 int         screen;
 407
 408                 for (screen = 0; screen < MI_NUM_SCREENS(mi); screen++) {
 409                         Display    *display = MI_DISPLAY(mi);
 410                         juliastruct *jp = &julias[screen];
 411                         int         buffer;
 412
 413                         if (jp->pointBuffer) {
 414                                 for (buffer = 0; buffer < jp->nbuffers; buffer++)
 415                                         if (jp->pointBuffer[buffer])
 416                                                 (void) free((void *) jp->pointBuffer[buffer]);
 417                                 (void) free((void *) jp->pointBuffer);
 418                         }
 419                         if (jp->stippledGC != None)
 420                                 XFreeGC(display, jp->stippledGC);
 421                         if (jp->pixmap != None)
 422                                 XFreePixmap(display, jp->pixmap);
 423 #ifndef HAVE_COCOA
 424                         if (jp->cursor)
 425                           XFreeCursor (display, jp->cursor);
 426 #endif
 427                 }
 428                 (void) free((void *) julias);
 429                 julias = NULL;
 430         }
 431 }
 432
 433 ENTRYPOINT void
 434 refresh_julia (ModeInfo * mi)
 435 {
 436         juliastruct *jp = &julias[MI_SCREEN(mi)];
 437
 438         jp->redrawing = 1;
 439         jp->redrawpos = 0;
 440 }
 441
 442 XSCREENSAVER_MODULE ("Julia", julia)