--- /dev/null
+/* -*- Mode: C; tab-width: 4 -*-
+ * julia --- continuously varying Julia set.
+ */
+#if !defined( lint ) && !defined( SABER )
+static const char sccsid[] = "@(#)julia.c 4.03 97/04/10 xlockmore";
+#endif
+
+/* Copyright (c) 1995 Sean McCullough <bankshot@mailhost.nmt.edu>.
+ *
+ * Permission to use, copy, modify, and distribute this software and its
+ * documentation for any purpose and without fee is hereby granted,
+ * provided that the above copyright notice appear in all copies and that
+ * both that copyright notice and this permission notice appear in
+ * supporting documentation.
+ *
+ * This file is provided AS IS with no warranties of any kind. The author
+ * shall have no liability with respect to the infringement of copyrights,
+ * trade secrets or any patents by this file or any part thereof. In no
+ * event will the author be liable for any lost revenue or profits or
+ * other special, indirect and consequential damages.
+ *
+ * Revision History:
+ * 28-May-97: jwz@netscape.com: added interactive frobbing with the mouse.
+ * 10-May-97: jwz@netscape.com: turned into a standalone program.
+ * 02-Dec-95: snagged boilerplate from hop.c
+ * used ifs {w0 = sqrt(x-c), w1 = -sqrt(x-c)} with random iteration
+ * to plot the julia set, and sinusoidially varied parameter for set
+ * and plotted parameter with a circle.
+ */
+
+/*-
+ * One thing to note is that batchcount is the *depth* of the search tree,
+ * so the number of points computed is 2^batchcount - 1. I use 8 or 9
+ * on a dx266 and it looks okay. The sinusoidal variation of the parameter
+ * might not be as interesting as it could, but it still gives an idea of
+ * the effect of the parameter.
+ */
+
+#ifdef STANDALONE
+# define PROGCLASS "Julia"
+# define HACK_INIT init_julia
+# define HACK_DRAW draw_julia
+# define julia_opts xlockmore_opts
+# define DEFAULTS "*count: 1000 \n" \
+ "*cycles: 20 \n" \
+ "*delay: 10000 \n" \
+ "*ncolors: 200 \n"
+# define UNIFORM_COLORS
+# include "xlockmore.h" /* in xscreensaver distribution */
+#else /* !STANDALONE */
+# include "xlock.h" /* in xlockmore distribution */
+#endif /* !STANDALONE */
+
+
+static Bool track_p;
+
+#define DEF_MOUSE "False"
+
+static XrmOptionDescRec opts[] =
+{
+ {"-mouse", ".julia.mouse", XrmoptionNoArg, (caddr_t) "on"},
+ {"+mouse", ".julia.mouse", XrmoptionNoArg, (caddr_t) "off"},
+};
+static argtype vars[] =
+{
+ {(caddr_t *) & track_p, "mouse", "Mouse", DEF_MOUSE, t_Bool},
+};
+static OptionStruct desc[] =
+{
+ {"-/+mouse", "turn on/off mouse tracking"},
+};
+
+ModeSpecOpt julia_opts = { 2, opts, 1, vars, desc };
+
+
+#define numpoints ((0x2<<jp->depth)-1)
+
+typedef struct {
+ int centerx;
+ int centery; /* center of the screen */
+ double cr;
+ double ci; /* julia params */
+ int depth;
+ int inc;
+ int circsize;
+ int erase;
+ int pix;
+ long itree;
+ int buffer;
+ int nbuffers;
+ int redrawing, redrawpos;
+ Pixmap pixmap;
+ Cursor cursor;
+ GC stippledGC;
+ XPoint **pointBuffer; /* pointer for XDrawPoints */
+
+} juliastruct;
+
+static juliastruct *julias = NULL;
+
+/* How many segments to draw per cycle when redrawing */
+#define REDRAWSTEP 3
+
+static void
+apply(juliastruct * jp, register double xr, register double xi, int d)
+{
+ double theta, r;
+
+ jp->pointBuffer[jp->buffer][jp->itree].x =
+ (int) (0.5 * xr * jp->centerx + jp->centerx);
+ jp->pointBuffer[jp->buffer][jp->itree].y =
+ (int) (0.5 * xi * jp->centery + jp->centery);
+ jp->itree++;
+
+ if (d > 0) {
+ xi -= jp->ci;
+ xr -= jp->cr;
+
+/* Avoid atan2: DOMAIN error message */
+ if (xi == 0.0 && xr == 0.0)
+ theta = 0.0;
+ else
+ theta = atan2(xi, xr) / 2.0;
+
+ /*r = pow(xi * xi + xr * xr, 0.25); */
+ r = sqrt(sqrt(xi * xi + xr * xr)); /* 3 times faster */
+
+ xr = r * cos(theta);
+ xi = r * sin(theta);
+
+ d--;
+ apply(jp, xr, xi, d);
+ apply(jp, -xr, -xi, d);
+ }
+}
+
+static void
+incr(ModeInfo * mi, juliastruct * jp)
+{
+ int cx, cy;
+
+ if (track_p)
+ {
+ Window r, c;
+ int rx, ry;
+ unsigned int m;
+ XQueryPointer(MI_DISPLAY(mi), MI_WINDOW(mi),
+ &r, &c, &rx, &ry, &cx, &cy, &m);
+ if (cx <= 0 || cy <= 0 ||
+ cx >= MI_WIN_WIDTH(mi) || cy >= MI_WIN_HEIGHT(mi))
+ goto NOTRACK;
+ }
+
+ if (track_p)
+ {
+ jp->cr = ((double) (cx + 2 - jp->centerx)) * 2 / jp->centerx;
+ jp->ci = ((double) (cy + 2 - jp->centery)) * 2 / jp->centery;
+ }
+ else
+ {
+ NOTRACK:
+ jp->cr = 1.5 * (sin(M_PI * (jp->inc / 300.0)) *
+ sin(jp->inc * M_PI / 200.0));
+ jp->ci = 1.5 * (cos(M_PI * (jp->inc / 300.0)) *
+ cos(jp->inc * M_PI / 200.0));
+
+ jp->cr += 0.5 * cos(M_PI * jp->inc / 400.0);
+ jp->ci += 0.5 * sin(M_PI * jp->inc / 400.0);
+ }
+}
+
+void
+init_julia(ModeInfo * mi)
+{
+ Display *display = MI_DISPLAY(mi);
+ Window window = MI_WINDOW(mi);
+ juliastruct *jp;
+ XGCValues gcv;
+ int i;
+
+ if (julias == NULL) {
+ if ((julias = (juliastruct *) calloc(MI_NUM_SCREENS(mi),
+ sizeof (juliastruct))) == NULL)
+ return;
+ }
+ jp = &julias[MI_SCREEN(mi)];
+
+ jp->centerx = MI_WIN_WIDTH(mi) / 2;
+ jp->centery = MI_WIN_HEIGHT(mi) / 2;
+
+ jp->depth = MI_BATCHCOUNT(mi);
+ if (jp->depth > 10)
+ jp->depth = 10;
+
+
+ if (track_p && !jp->cursor)
+ {
+ Pixmap bit;
+ XColor black;
+ black.red = black.green = black.blue = 0;
+ black.flags = DoRed|DoGreen|DoBlue;
+ bit = XCreatePixmapFromBitmapData (display, window, "\000", 1, 1,
+ MI_WIN_BLACK_PIXEL(mi),
+ MI_WIN_BLACK_PIXEL(mi), 1);
+ jp->cursor = XCreatePixmapCursor (display, bit, bit, &black, &black,
+ 0, 0);
+ XFreePixmap (display, bit);
+ }
+
+ if (jp->pixmap != None &&
+ jp->circsize != (MIN(jp->centerx, jp->centery) / 60) * 2 + 1) {
+ XFreePixmap(display, jp->pixmap);
+ jp->pixmap = None;
+ }
+ if (jp->pixmap == None) {
+ GC fg_gc = None, bg_gc = None;
+
+ jp->circsize = (MIN(jp->centerx, jp->centery) / 96) * 2 + 1;
+ jp->pixmap = XCreatePixmap(display, window, jp->circsize, jp->circsize, 1);
+ gcv.foreground = 1;
+ fg_gc = XCreateGC(display, jp->pixmap, GCForeground, &gcv);
+ gcv.foreground = 0;
+ bg_gc = XCreateGC(display, jp->pixmap, GCForeground, &gcv);
+ XFillRectangle(display, jp->pixmap, bg_gc,
+ 0, 0, jp->circsize, jp->circsize);
+ if (jp->circsize < 2)
+ XDrawPoint(display, jp->pixmap, fg_gc, 0, 0);
+ else
+ XFillArc(display, jp->pixmap, fg_gc,
+ 0, 0, jp->circsize, jp->circsize, 0, 23040);
+ if (fg_gc != None)
+ XFreeGC(display, fg_gc);
+ if (bg_gc != None)
+ XFreeGC(display, bg_gc);
+ }
+
+ if (MI_WIN_IS_INROOT(mi))
+ ;
+ else if (jp->circsize > 0)
+ XDefineCursor (display, window, jp->cursor);
+ else
+ XUndefineCursor (display, window);
+
+ if (!jp->stippledGC) {
+ gcv.foreground = MI_WIN_BLACK_PIXEL(mi);
+ gcv.background = MI_WIN_BLACK_PIXEL(mi);
+ if ((jp->stippledGC = XCreateGC(display, window,
+ GCForeground | GCBackground, &gcv)) == None)
+ return;
+ }
+ if (MI_NPIXELS(mi) > 2)
+ jp->pix = NRAND(MI_NPIXELS(mi));
+ jp->inc = ((LRAND() & 1) * 2 - 1) * NRAND(200);
+ jp->nbuffers = (MI_CYCLES(mi) + 1);
+ if (!jp->pointBuffer)
+ jp->pointBuffer = (XPoint **) calloc(jp->nbuffers, sizeof (XPoint *));
+ for (i = 0; i < jp->nbuffers; ++i)
+ if (jp->pointBuffer[i])
+ (void) memset((char *) jp->pointBuffer[i], 0,
+ numpoints * sizeof (XPoint));
+ else
+ jp->pointBuffer[i] = (XPoint *) calloc(numpoints, sizeof (XPoint));
+ jp->buffer = 0;
+ jp->redrawing = 0;
+ jp->erase = 0;
+ XClearWindow(display, window);
+}
+
+
+/* hack: moved here by jwz. */
+#define ERASE_IMAGE(d,w,g,x,y,xl,yl,xs,ys) \
+if (yl<y) \
+(y<yl+ys)?XFillRectangle(d,w,g,xl,yl,xs,y-yl): \
+XFillRectangle(d,w,g,xl,yl,xs,ys); \
+else if (yl>y) \
+(y>yl-ys)?XFillRectangle(d,w,g,xl,y+ys,xs,yl-y): \
+XFillRectangle(d,w,g,xl,yl,xs,ys); \
+if (xl<x) \
+(x<xl+xs)?XFillRectangle(d,w,g,xl,yl,x-xl,ys): \
+XFillRectangle(d,w,g,xl,yl,xs,ys); \
+else if (xl>x) \
+(x>xl-xs)?XFillRectangle(d,w,g,x+xs,yl,xl-x,ys): \
+XFillRectangle(d,w,g,xl,yl,xs,ys)
+
+
+void
+draw_julia(ModeInfo * mi)
+{
+ Display *display = MI_DISPLAY(mi);
+ Window window = MI_WINDOW(mi);
+ GC gc = MI_GC(mi);
+ juliastruct *jp = &julias[MI_SCREEN(mi)];
+ double r, theta;
+ register double xr = 0.0, xi = 0.0;
+ int k = 64, rnd = 0, i, j;
+ XPoint *xp = jp->pointBuffer[jp->buffer], old_circle, new_circle;
+
+ old_circle.x = (int) (jp->centerx * jp->cr / 2) + jp->centerx - 2;
+ old_circle.y = (int) (jp->centery * jp->ci / 2) + jp->centery - 2;
+ incr(mi, jp);
+ new_circle.x = (int) (jp->centerx * jp->cr / 2) + jp->centerx - 2;
+ new_circle.y = (int) (jp->centery * jp->ci / 2) + jp->centery - 2;
+ XSetForeground(display, gc, MI_WIN_BLACK_PIXEL(mi));
+ ERASE_IMAGE(display, window, gc, new_circle.x, new_circle.y,
+ old_circle.x, old_circle.y, jp->circsize, jp->circsize);
+ /* draw a circle at the c-parameter so you can see it's effect on the
+ structure of the julia set */
+ XSetTSOrigin(display, jp->stippledGC, new_circle.x, new_circle.y);
+ XSetForeground(display, jp->stippledGC, MI_WIN_WHITE_PIXEL(mi));
+ XSetStipple(display, jp->stippledGC, jp->pixmap);
+ XSetFillStyle(display, jp->stippledGC, FillOpaqueStippled);
+ XFillRectangle(display, window, jp->stippledGC, new_circle.x, new_circle.y,
+ jp->circsize, jp->circsize);
+ XFlush(display);
+ if (jp->erase == 1) {
+ XDrawPoints(display, window, gc,
+ jp->pointBuffer[jp->buffer], numpoints, CoordModeOrigin);
+ }
+ jp->inc++;
+ if (MI_NPIXELS(mi) > 2) {
+ XSetForeground(display, gc, MI_PIXEL(mi, jp->pix));
+ if (++jp->pix >= MI_NPIXELS(mi))
+ jp->pix = 0;
+ } else
+ XSetForeground(display, gc, MI_WIN_WHITE_PIXEL(mi));
+ while (k--) {
+
+ /* save calls to LRAND by using bit shifts over and over on the same
+ int for 32 iterations, then get a new random int */
+ if (!(k % 32))
+ rnd = LRAND();
+
+ /* complex sqrt: x^0.5 = radius^0.5*(cos(theta/2) + i*sin(theta/2)) */
+
+ xi -= jp->ci;
+ xr -= jp->cr;
+
+ /* Avoid atan2: DOMAIN error message */
+ if (xi == 0.0 && xr == 0.0)
+ theta = 0.0;
+ else
+ theta = atan2(xi, xr) / 2.0;
+
+ /*r = pow(xi * xi + xr * xr, 0.25); */
+ r = sqrt(sqrt(xi * xi + xr * xr)); /* 3 times faster */
+
+ xr = r * cos(theta);
+ xi = r * sin(theta);
+
+ if ((rnd >> (k % 32)) & 0x1) {
+ xi = -xi;
+ xr = -xr;
+ }
+ xp->x = jp->centerx + (int) ((jp->centerx >> 1) * xr);
+ xp->y = jp->centery + (int) ((jp->centery >> 1) * xi);
+ xp++;
+ }
+
+ jp->itree = 0;
+ apply(jp, xr, xi, jp->depth);
+
+ XDrawPoints(display, window, gc,
+ jp->pointBuffer[jp->buffer], numpoints, CoordModeOrigin);
+
+ jp->buffer++;
+ if (jp->buffer > jp->nbuffers - 1) {
+ jp->buffer -= jp->nbuffers;
+ jp->erase = 1;
+ }
+ if (jp->redrawing) {
+ for (i = 0; i < REDRAWSTEP; i++) {
+ j = (jp->buffer - jp->redrawpos + jp->nbuffers) % jp->nbuffers;
+ XDrawPoints(display, window, gc,
+ jp->pointBuffer[j], numpoints, CoordModeOrigin);
+
+ if (++(jp->redrawpos) >= jp->nbuffers) {
+ jp->redrawing = 0;
+ break;
+ }
+ }
+ }
+}
+
+void
+release_julia(ModeInfo * mi)
+{
+ if (julias != NULL) {
+ int screen;
+
+ for (screen = 0; screen < MI_NUM_SCREENS(mi); screen++) {
+ Display *display = MI_DISPLAY(mi);
+ juliastruct *jp = &julias[screen];
+ int buffer;
+
+ if (jp->pointBuffer) {
+ for (buffer = 0; buffer < jp->nbuffers; buffer++)
+ if (jp->pointBuffer[buffer])
+ (void) free((void *) jp->pointBuffer[buffer]);
+ (void) free((void *) jp->pointBuffer);
+ }
+ if (jp->stippledGC != None)
+ XFreeGC(display, jp->stippledGC);
+ if (jp->pixmap != None)
+ XFreePixmap(display, jp->pixmap);
+ if (jp->cursor)
+ XFreeCursor (display, jp->cursor);
+ }
+ (void) free((void *) julias);
+ julias = NULL;
+ }
+}
+
+void
+refresh_julia(ModeInfo * mi)
+{
+ juliastruct *jp = &julias[MI_SCREEN(mi)];
+
+ jp->redrawing = 1;
+ jp->redrawpos = 0;
+}
projects / xscreensaver / blobdiff