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Diffstat (limited to 'hacks/julia.c')
| -rw-r--r-- | hacks/julia.c | 442 |
1 files changed, 442 insertions, 0 deletions
diff --git a/hacks/julia.c b/hacks/julia.c new file mode 100644 index 0000000..7311ce7 --- /dev/null +++ b/hacks/julia.c @@ -0,0 +1,442 @@ +/* -*- Mode: C; tab-width: 4 -*- + * julia --- continuously varying Julia set. + */ +#if 0 +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: + * 10-Jun-06: j.grahl@ucl.ac.uk: tweaked functions for parameter of Julia set + * 28-May-97: jwz@jwz.org: added interactive frobbing with the mouse. + * 10-May-97: jwz@jwz.org: 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 DEFAULTS "*count: 1000 \n" \ + "*cycles: 20 \n" \ + "*delay: 10000 \n" \ + "*ncolors: 200 \n" \ + "*fpsSolid: true \n" \ + "*ignoreRotation: True \n" \ + +# define UNIFORM_COLORS +# define release_julia 0 +# define reshape_julia 0 +# include "xlockmore.h" /* in xscreensaver distribution */ +#else /* !STANDALONE */ +# include "xlock.h" /* in xlockmore distribution */ +#endif /* !STANDALONE */ + + +#define DEF_MOUSE "False" + +ENTRYPOINT ModeSpecOpt julia_opts = { 0, }; + + +#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; +#ifndef HAVE_JWXYZ + Cursor cursor; +#endif + GC stippledGC; + XPoint **pointBuffer; /* pointer for XDrawPoints */ + Bool button_down_p; + int mouse_x, mouse_y; + +} 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) +{ + if (jp->button_down_p) + { + jp->cr = ((double) (jp->mouse_x + 2 - jp->centerx)) * 2 / jp->centerx; + jp->ci = ((double) (jp->mouse_y + 2 - jp->centery)) * 2 / jp->centery; + } + else + { +#if 0 + 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); +#else + jp->cr = 1.5 * (sin(M_PI * (jp->inc / 290.0)) * + sin(jp->inc * M_PI / 210.0)); + jp->ci = 1.5 * (cos(M_PI * (jp->inc / 310.0)) * + cos(jp->inc * M_PI / 190.0)); + + jp->cr += 0.5 * cos(M_PI * jp->inc / 395.0); + jp->ci += 0.5 * sin(M_PI * jp->inc / 410.0); +#endif + } +} + +ENTRYPOINT void +init_julia(ModeInfo * mi) +{ + Display *display = MI_DISPLAY(mi); + Window window = MI_WINDOW(mi); + juliastruct *jp; + XGCValues gcv; + int i; + + MI_INIT (mi, julias); + 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; + + +#ifndef HAVE_JWXYZ + if (jp->button_down_p && !jp->cursor && !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); + } +#endif /* HAVE_JWXYZ */ + + 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 = MAX(8, (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); + } + +#ifndef HAVE_JWXYZ + if (MI_WIN_IS_INROOT(mi)) + ; + else if (jp->circsize > 0) + XDefineCursor (display, window, jp->cursor); + else + XUndefineCursor (display, window); +#endif /* HAVE_JWXYZ */ + + 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); +} + + +ENTRYPOINT Bool +julia_handle_event (ModeInfo *mi, XEvent *event) +{ + juliastruct *jp = &julias[MI_SCREEN(mi)]; + + if (event->xany.type == ButtonPress && + event->xbutton.button == Button1) + { + jp->button_down_p = True; + jp->mouse_x = event->xbutton.x; + jp->mouse_y = event->xbutton.y; + return True; + } + else if (event->xany.type == ButtonRelease && + event->xbutton.button == Button1) + { + jp->button_down_p = False; + return True; + } + else if (event->xany.type == MotionNotify && jp->button_down_p) + { + jp->mouse_x = event->xmotion.x; + jp->mouse_y = event->xmotion.y; + return True; + } + + return False; +} + + + +/* 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) + + +ENTRYPOINT 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)); + XFillArc(display, window, gc, + old_circle.x-jp->circsize/2-2, + old_circle.y-jp->circsize/2-2, + jp->circsize+4, jp->circsize+4, + 0, 360*64); + /* draw a circle at the c-parameter so you can see it's effect on the + structure of the julia set */ + XSetForeground(display, jp->stippledGC, MI_WIN_WHITE_PIXEL(mi)); +#ifndef HAVE_JWXYZ + XSetTSOrigin(display, jp->stippledGC, new_circle.x, new_circle.y); + XSetStipple(display, jp->stippledGC, jp->pixmap); + XSetFillStyle(display, jp->stippledGC, FillOpaqueStippled); +#endif /* HAVE_JWXYZ */ + XDrawArc(display, window, jp->stippledGC, + new_circle.x-jp->circsize/2, + new_circle.y-jp->circsize/2, + jp->circsize, jp->circsize, + 0, 360*64); + + 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; + } + } + } +} + +ENTRYPOINT void +free_julia (ModeInfo * mi) +{ + Display *display = MI_DISPLAY(mi); + juliastruct *jp = &julias[MI_SCREEN(mi)]; + 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); +#ifndef HAVE_JWXYZ + if (jp->cursor) + XFreeCursor (display, jp->cursor); +#endif +} + +#ifndef STANDALONE +ENTRYPOINT void +refresh_julia (ModeInfo * mi) +{ + juliastruct *jp = &julias[MI_SCREEN(mi)]; + + jp->redrawing = 1; + jp->redrawpos = 0; +} +#endif + +XSCREENSAVER_MODULE ("Julia", julia) |