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/* -*- Mode: C; tab-width: 4 -*- */
/* sierpinski --- Sierpinski's triangle fractal */
#if 0
static const char sccsid[] = "@(#)sierpinski.c 5.00 2000/11/01 xlockmore";
#endif
/*-
* Copyright (c) 1996 by Desmond Daignault
*
* 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.
*
* Dots initially appear where they "should not". Later they get
* "focused". This is correct behavior.
*
* Revision History:
* 01-Nov-2000: Allocation checks
* 18-Sep-1997: 3D version Antti Kuntsi <kuntsi@iki.fi>.
* 20-May-1997: Changed the name tri to sierpinski for more compatiblity
* 10-May-1997: Jamie Zawinski <jwz@jwz.org> compatible with xscreensaver
* 05-Sep-1996: Desmond Daignault Datatimes Incorporated
* <tekdd@dtol.datatimes.com> .
*/
#ifdef STANDALONE
# define MODE_sierpinski
# define DEFAULTS "*delay: 400000 \n" \
"*count: 2000 \n" \
"*cycles: 100 \n" \
"*ncolors: 64 \n" \
"*fpsSolid: true \n" \
"*ignoreRotation: True \n" \
"*lowrez: True \n" \
# define BRIGHT_COLORS
# define release_sierpinski 0
# define reshape_sierpinski 0
# define sierpinski_handle_event 0
# include "xlockmore.h" /* in xscreensaver distribution */
#else /* STANDALONE */
# include "xlock.h" /* in xlockmore distribution */
#endif /* STANDALONE */
#ifdef MODE_sierpinski
ENTRYPOINT ModeSpecOpt sierpinski_opts =
{0, (XrmOptionDescRec *) NULL, 0, (argtype *) NULL, (OptionStruct *) NULL};
#ifdef USE_MODULES
ModStruct sierpinski_description =
{"sierpinski", "init_sierpinski", "draw_sierpinski", (char *) NULL,
"refresh_sierpinski", "init_sierpinski", "free_sierpinski", &sierpinski_opts,
400000, 2000, 100, 1, 64, 1.0, "",
"Shows Sierpinski's triangle", 0, NULL};
#endif
#define MAXCORNERS 4
typedef struct {
int width, height;
int time;
int px, py;
int total_npoints;
int corners;
int npoints[MAXCORNERS];
unsigned long colors[MAXCORNERS];
XPoint *pointBuffer[MAXCORNERS];
XPoint vertex[MAXCORNERS];
} sierpinskistruct;
static sierpinskistruct *tris = (sierpinskistruct *) NULL;
static void
startover(ModeInfo * mi)
{
int j;
sierpinskistruct *sp = &tris[MI_SCREEN(mi)];
if (MI_NPIXELS(mi) > 2) {
if (sp->corners == 3) {
sp->colors[0] = (NRAND(MI_NPIXELS(mi)));
sp->colors[1] = (sp->colors[0] + MI_NPIXELS(mi) / 7 +
NRAND(2 * MI_NPIXELS(mi) / 7 + 1)) % MI_NPIXELS(mi);
sp->colors[2] = (sp->colors[0] + 4 * MI_NPIXELS(mi) / 7 +
NRAND(2 * MI_NPIXELS(mi) / 7 + 1)) % MI_NPIXELS(mi);
} else if (sp->corners == 4) {
sp->colors[0] = (NRAND(MI_NPIXELS(mi)));
sp->colors[1] = (sp->colors[0] + MI_NPIXELS(mi) / 7 +
NRAND(MI_NPIXELS(mi) / 7 + 1)) % MI_NPIXELS(mi);
sp->colors[2] = (sp->colors[0] + 3 * MI_NPIXELS(mi) / 7 +
NRAND(MI_NPIXELS(mi) / 7 + 1)) % MI_NPIXELS(mi);
sp->colors[3] = (sp->colors[0] + 5 * MI_NPIXELS(mi) / 7 +
NRAND(MI_NPIXELS(mi) / 7 + 1)) % MI_NPIXELS(mi);
} else {
(void) fprintf(stderr, "colors not set for %d corners\n", sp->corners);
}
}
for (j = 0; j < sp->corners; j++) {
sp->vertex[j].x = NRAND(sp->width);
sp->vertex[j].y = NRAND(sp->height);
}
sp->px = NRAND(sp->width);
sp->py = NRAND(sp->height);
sp->time = 0;
MI_CLEARWINDOW(mi);
}
ENTRYPOINT void
free_sierpinski(ModeInfo * mi)
{
sierpinskistruct *sp = &tris[MI_SCREEN(mi)];
int corner;
for (corner = 0; corner < MAXCORNERS; corner++)
if (sp->pointBuffer[corner] != NULL) {
(void) free((void *) sp->pointBuffer[corner]);
sp->pointBuffer[corner] = (XPoint *) NULL;
}
}
ENTRYPOINT void
init_sierpinski(ModeInfo * mi)
{
int i;
sierpinskistruct *sp;
MI_INIT (mi, tris);
sp = &tris[MI_SCREEN(mi)];
sp->width = MI_WIDTH(mi);
sp->height = MI_HEIGHT(mi);
sp->total_npoints = MI_COUNT(mi);
if (sp->total_npoints < 1)
sp->total_npoints = 1;
sp->corners = MI_SIZE(mi);
if (sp->corners < 3 || sp->corners > 4) {
sp->corners = (int) (LRAND() & 1) + 3;
}
for (i = 0; i < sp->corners; i++) {
if (!sp->pointBuffer[i])
if ((sp->pointBuffer[i] = (XPoint *) malloc(sp->total_npoints *
sizeof (XPoint))) == NULL) {
free_sierpinski(mi);
return;
}
}
startover(mi);
}
ENTRYPOINT void
draw_sierpinski(ModeInfo * mi)
{
Display *display = MI_DISPLAY(mi);
GC gc = MI_GC(mi);
XPoint *xp[MAXCORNERS];
int i, v;
sierpinskistruct *sp;
if (tris == NULL)
return;
sp = &tris[MI_SCREEN(mi)];
if (sp->pointBuffer[0] == NULL)
return;
MI_IS_DRAWN(mi) = True;
if (MI_NPIXELS(mi) <= 2)
XSetForeground(display, gc, MI_WHITE_PIXEL(mi));
for (i = 0; i < sp->corners; i++)
xp[i] = sp->pointBuffer[i];
for (i = 0; i < sp->total_npoints; i++) {
v = NRAND(sp->corners);
sp->px = (sp->px + sp->vertex[v].x) / 2;
sp->py = (sp->py + sp->vertex[v].y) / 2;
xp[v]->x = sp->px;
xp[v]->y = sp->py;
xp[v]++;
sp->npoints[v]++;
}
for (i = 0; i < sp->corners; i++) {
if (MI_NPIXELS(mi) > 2)
XSetForeground(display, gc, MI_PIXEL(mi, sp->colors[i]));
XDrawPoints(display, MI_WINDOW(mi), gc, sp->pointBuffer[i], sp->npoints[i],
CoordModeOrigin);
sp->npoints[i] = 0;
}
if (++sp->time >= MI_CYCLES(mi))
startover(mi);
}
#ifndef STANDALONE
ENTRYPOINT void
refresh_sierpinski(ModeInfo * mi)
{
MI_CLEARWINDOW(mi);
}
#endif
XSCREENSAVER_MODULE ("Sierpinski", sierpinski)
#endif /* MODE_sierpinski */
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