1 /* -*- Mode: C; tab-width: 4 -*- */
2 /* sierpinski --- Sierpinski's triangle fractal */
5 static const char sccsid[] = "@(#)sierpinski.c 5.00 2000/11/01 xlockmore";
9 * Copyright (c) 1996 by Desmond Daignault
11 * Permission to use, copy, modify, and distribute this software and its
12 * documentation for any purpose and without fee is hereby granted,
13 * provided that the above copyright notice appear in all copies and that
14 * both that copyright notice and this permission notice appear in
15 * supporting documentation.
17 * This file is provided AS IS with no warranties of any kind. The author
18 * shall have no liability with respect to the infringement of copyrights,
19 * trade secrets or any patents by this file or any part thereof. In no
20 * event will the author be liable for any lost revenue or profits or
21 * other special, indirect and consequential damages.
23 * Dots initially appear where they "should not". Later they get
24 * "focused". This is correct behavior.
27 * 01-Nov-2000: Allocation checks
28 * 18-Sep-1997: 3D version Antti Kuntsi <kuntsi@iki.fi>.
29 * 20-May-1997: Changed the name tri to sierpinski for more compatiblity
30 * 10-May-1997: Jamie Zawinski <jwz@jwz.org> compatible with xscreensaver
31 * 05-Sep-1996: Desmond Daignault Datatimes Incorporated
32 * <tekdd@dtol.datatimes.com> .
36 # define MODE_sierpinski
37 # define DEFAULTS "*delay: 400000 \n" \
41 # define BRIGHT_COLORS
42 # define reshape_sierpinski 0
43 # define sierpinski_handle_event 0
44 # include "xlockmore.h" /* in xscreensaver distribution */
45 #else /* STANDALONE */
46 # include "xlock.h" /* in xlockmore distribution */
47 #endif /* STANDALONE */
49 #ifdef MODE_sierpinski
51 ENTRYPOINT ModeSpecOpt sierpinski_opts =
52 {0, (XrmOptionDescRec *) NULL, 0, (argtype *) NULL, (OptionStruct *) NULL};
55 ModStruct sierpinski_description =
56 {"sierpinski", "init_sierpinski", "draw_sierpinski", "release_sierpinski",
57 "refresh_sierpinski", "init_sierpinski", (char *) NULL, &sierpinski_opts,
58 400000, 2000, 100, 1, 64, 1.0, "",
59 "Shows Sierpinski's triangle", 0, NULL};
71 int npoints[MAXCORNERS];
72 unsigned long colors[MAXCORNERS];
73 XPoint *pointBuffer[MAXCORNERS];
74 XPoint vertex[MAXCORNERS];
77 static sierpinskistruct *tris = (sierpinskistruct *) NULL;
80 startover(ModeInfo * mi)
83 sierpinskistruct *sp = &tris[MI_SCREEN(mi)];
85 if (MI_NPIXELS(mi) > 2) {
86 if (sp->corners == 3) {
87 sp->colors[0] = (NRAND(MI_NPIXELS(mi)));
88 sp->colors[1] = (sp->colors[0] + MI_NPIXELS(mi) / 7 +
89 NRAND(2 * MI_NPIXELS(mi) / 7 + 1)) % MI_NPIXELS(mi);
90 sp->colors[2] = (sp->colors[0] + 4 * MI_NPIXELS(mi) / 7 +
91 NRAND(2 * MI_NPIXELS(mi) / 7 + 1)) % MI_NPIXELS(mi);
92 } else if (sp->corners == 4) {
93 sp->colors[0] = (NRAND(MI_NPIXELS(mi)));
94 sp->colors[1] = (sp->colors[0] + MI_NPIXELS(mi) / 7 +
95 NRAND(MI_NPIXELS(mi) / 7 + 1)) % MI_NPIXELS(mi);
96 sp->colors[2] = (sp->colors[0] + 3 * MI_NPIXELS(mi) / 7 +
97 NRAND(MI_NPIXELS(mi) / 7 + 1)) % MI_NPIXELS(mi);
98 sp->colors[3] = (sp->colors[0] + 5 * MI_NPIXELS(mi) / 7 +
99 NRAND(MI_NPIXELS(mi) / 7 + 1)) % MI_NPIXELS(mi);
101 (void) fprintf(stderr, "colors not set for %d corners\n", sp->corners);
104 for (j = 0; j < sp->corners; j++) {
105 sp->vertex[j].x = NRAND(sp->width);
106 sp->vertex[j].y = NRAND(sp->height);
108 sp->px = NRAND(sp->width);
109 sp->py = NRAND(sp->height);
116 free_sierpinski(sierpinskistruct *sp)
120 for (corner = 0; corner < MAXCORNERS; corner++)
121 if (sp->pointBuffer[corner] != NULL) {
122 (void) free((void *) sp->pointBuffer[corner]);
123 sp->pointBuffer[corner] = (XPoint *) NULL;
128 init_sierpinski(ModeInfo * mi)
131 sierpinskistruct *sp;
134 if ((tris = (sierpinskistruct *) calloc(MI_NUM_SCREENS(mi),
135 sizeof (sierpinskistruct))) == NULL)
138 sp = &tris[MI_SCREEN(mi)];
140 sp->width = MI_WIDTH(mi);
141 sp->height = MI_HEIGHT(mi);
143 sp->total_npoints = MI_COUNT(mi);
144 if (sp->total_npoints < 1)
145 sp->total_npoints = 1;
146 sp->corners = MI_SIZE(mi);
147 if (sp->corners < 3 || sp->corners > 4) {
148 sp->corners = (int) (LRAND() & 1) + 3;
150 for (i = 0; i < sp->corners; i++) {
151 if (!sp->pointBuffer[i])
152 if ((sp->pointBuffer[i] = (XPoint *) malloc(sp->total_npoints *
153 sizeof (XPoint))) == NULL) {
162 draw_sierpinski(ModeInfo * mi)
164 Display *display = MI_DISPLAY(mi);
166 XPoint *xp[MAXCORNERS];
168 sierpinskistruct *sp;
172 sp = &tris[MI_SCREEN(mi)];
173 if (sp->pointBuffer[0] == NULL)
176 MI_IS_DRAWN(mi) = True;
177 if (MI_NPIXELS(mi) <= 2)
178 XSetForeground(display, gc, MI_WHITE_PIXEL(mi));
179 for (i = 0; i < sp->corners; i++)
180 xp[i] = sp->pointBuffer[i];
181 for (i = 0; i < sp->total_npoints; i++) {
182 v = NRAND(sp->corners);
183 sp->px = (sp->px + sp->vertex[v].x) / 2;
184 sp->py = (sp->py + sp->vertex[v].y) / 2;
190 for (i = 0; i < sp->corners; i++) {
191 if (MI_NPIXELS(mi) > 2)
192 XSetForeground(display, gc, MI_PIXEL(mi, sp->colors[i]));
193 XDrawPoints(display, MI_WINDOW(mi), gc, sp->pointBuffer[i], sp->npoints[i],
197 if (++sp->time >= MI_CYCLES(mi))
202 release_sierpinski(ModeInfo * mi)
207 for (screen = 0; screen < MI_NUM_SCREENS(mi); screen++)
208 free_sierpinski(&tris[screen]);
209 (void) free((void *) tris);
210 tris = (sierpinskistruct *) NULL;
215 refresh_sierpinski(ModeInfo * mi)
220 XSCREENSAVER_MODULE ("Sierpinski", sierpinski)
222 #endif /* MODE_sierpinski */