1 /* -*- Mode: C; tab-width: 4 -*- */
2 /* sierpinski --- Sierpinski's triangle fractal */
4 #if !defined( lint ) && !defined( SABER )
5 static const char sccsid[] = "@(#)sierpinski.c 5.00 2000/11/01 xlockmore";
10 * Copyright (c) 1996 by Desmond Daignault
12 * Permission to use, copy, modify, and distribute this software and its
13 * documentation for any purpose and without fee is hereby granted,
14 * provided that the above copyright notice appear in all copies and that
15 * both that copyright notice and this permission notice appear in
16 * supporting documentation.
18 * This file is provided AS IS with no warranties of any kind. The author
19 * shall have no liability with respect to the infringement of copyrights,
20 * trade secrets or any patents by this file or any part thereof. In no
21 * event will the author be liable for any lost revenue or profits or
22 * other special, indirect and consequential damages.
24 * Dots initially appear where they "should not". Later they get
25 * "focused". This is correct behavior.
28 * 01-Nov-2000: Allocation checks
29 * 18-Sep-1997: 3D version Antti Kuntsi <kuntsi@iki.fi>.
30 * 20-May-1997: Changed the name tri to sierpinski for more compatiblity
31 * 10-May-1997: Jamie Zawinski <jwz@jwz.org> compatible with xscreensaver
32 * 05-Sep-1996: Desmond Daignault Datatimes Incorporated
33 * <tekdd@dtol.datatimes.com> .
37 #define MODE_sierpinski
38 #define PROGCLASS "Sierpinski"
39 #define HACK_INIT init_sierpinski
40 #define HACK_DRAW draw_sierpinski
41 #define sierpinski_opts xlockmore_opts
42 #define DEFAULTS "*delay: 400000 \n" \
47 #include "xlockmore.h" /* in xscreensaver distribution */
48 #else /* STANDALONE */
49 #include "xlock.h" /* in xlockmore distribution */
50 #endif /* STANDALONE */
52 #ifdef MODE_sierpinski
54 ModeSpecOpt sierpinski_opts =
55 {0, (XrmOptionDescRec *) NULL, 0, (argtype *) NULL, (OptionStruct *) NULL};
58 ModStruct sierpinski_description =
59 {"sierpinski", "init_sierpinski", "draw_sierpinski", "release_sierpinski",
60 "refresh_sierpinski", "init_sierpinski", (char *) NULL, &sierpinski_opts,
61 400000, 2000, 100, 1, 64, 1.0, "",
62 "Shows Sierpinski's triangle", 0, NULL};
74 int npoints[MAXCORNERS];
75 unsigned long colors[MAXCORNERS];
76 XPoint *pointBuffer[MAXCORNERS];
77 XPoint vertex[MAXCORNERS];
80 static sierpinskistruct *tris = (sierpinskistruct *) NULL;
83 startover(ModeInfo * mi)
86 sierpinskistruct *sp = &tris[MI_SCREEN(mi)];
88 if (MI_NPIXELS(mi) > 2) {
89 if (sp->corners == 3) {
90 sp->colors[0] = (NRAND(MI_NPIXELS(mi)));
91 sp->colors[1] = (sp->colors[0] + MI_NPIXELS(mi) / 7 +
92 NRAND(2 * MI_NPIXELS(mi) / 7 + 1)) % MI_NPIXELS(mi);
93 sp->colors[2] = (sp->colors[0] + 4 * MI_NPIXELS(mi) / 7 +
94 NRAND(2 * MI_NPIXELS(mi) / 7 + 1)) % MI_NPIXELS(mi);
95 } else if (sp->corners == 4) {
96 sp->colors[0] = (NRAND(MI_NPIXELS(mi)));
97 sp->colors[1] = (sp->colors[0] + MI_NPIXELS(mi) / 7 +
98 NRAND(MI_NPIXELS(mi) / 7 + 1)) % MI_NPIXELS(mi);
99 sp->colors[2] = (sp->colors[0] + 3 * MI_NPIXELS(mi) / 7 +
100 NRAND(MI_NPIXELS(mi) / 7 + 1)) % MI_NPIXELS(mi);
101 sp->colors[3] = (sp->colors[0] + 5 * MI_NPIXELS(mi) / 7 +
102 NRAND(MI_NPIXELS(mi) / 7 + 1)) % MI_NPIXELS(mi);
104 (void) fprintf(stderr, "colors not set for %d corners\n", sp->corners);
107 for (j = 0; j < sp->corners; j++) {
108 sp->vertex[j].x = NRAND(sp->width);
109 sp->vertex[j].y = NRAND(sp->height);
111 sp->px = NRAND(sp->width);
112 sp->py = NRAND(sp->height);
119 free_sierpinski(sierpinskistruct *sp)
123 for (corner = 0; corner < MAXCORNERS; corner++)
124 if (sp->pointBuffer[corner] != NULL) {
125 (void) free((void *) sp->pointBuffer[corner]);
126 sp->pointBuffer[corner] = (XPoint *) NULL;
131 init_sierpinski(ModeInfo * mi)
134 sierpinskistruct *sp;
137 if ((tris = (sierpinskistruct *) calloc(MI_NUM_SCREENS(mi),
138 sizeof (sierpinskistruct))) == NULL)
141 sp = &tris[MI_SCREEN(mi)];
143 sp->width = MI_WIDTH(mi);
144 sp->height = MI_HEIGHT(mi);
146 sp->total_npoints = MI_COUNT(mi);
147 if (sp->total_npoints < 1)
148 sp->total_npoints = 1;
149 sp->corners = MI_SIZE(mi);
150 if (sp->corners < 3 || sp->corners > 4) {
151 sp->corners = (int) (LRAND() & 1) + 3;
153 for (i = 0; i < sp->corners; i++) {
154 if (!sp->pointBuffer[i])
155 if ((sp->pointBuffer[i] = (XPoint *) malloc(sp->total_npoints *
156 sizeof (XPoint))) == NULL) {
165 draw_sierpinski(ModeInfo * mi)
167 Display *display = MI_DISPLAY(mi);
169 XPoint *xp[MAXCORNERS];
171 sierpinskistruct *sp;
175 sp = &tris[MI_SCREEN(mi)];
176 if (sp->pointBuffer[0] == NULL)
179 MI_IS_DRAWN(mi) = True;
180 if (MI_NPIXELS(mi) <= 2)
181 XSetForeground(display, gc, MI_WHITE_PIXEL(mi));
182 for (i = 0; i < sp->corners; i++)
183 xp[i] = sp->pointBuffer[i];
184 for (i = 0; i < sp->total_npoints; i++) {
185 v = NRAND(sp->corners);
186 sp->px = (sp->px + sp->vertex[v].x) / 2;
187 sp->py = (sp->py + sp->vertex[v].y) / 2;
193 for (i = 0; i < sp->corners; i++) {
194 if (MI_NPIXELS(mi) > 2)
195 XSetForeground(display, gc, MI_PIXEL(mi, sp->colors[i]));
196 XDrawPoints(display, MI_WINDOW(mi), gc, sp->pointBuffer[i], sp->npoints[i],
200 if (++sp->time >= MI_CYCLES(mi))
205 release_sierpinski(ModeInfo * mi)
210 for (screen = 0; screen < MI_NUM_SCREENS(mi); screen++)
211 free_sierpinski(&tris[screen]);
212 (void) free((void *) tris);
213 tris = (sierpinskistruct *) NULL;
218 refresh_sierpinski(ModeInfo * mi)
223 #endif /* MODE_sierpinski */