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braid.c @ 20148

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Revision 20148, 13.5 KB checked in by ghudson, 21 years ago (diff)
This commit was generated by cvs2svn to compensate for changes in r20147, which included commits to RCS files with non-trunk default branches.

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1	/* -- Mode: C; tab-width: 4 -- */
2	/*-
3	* braid --- random braids around a circle and then changes the color in
4	* a rotational pattern
5	*/
6
7	#if 0
8	static const char sccsid[] = "@(#)braid.c 5.00 2000/11/01 xlockmore";
9	#endif
10
11	/*-
12	* Copyright (c) 1995 by John Neil.
13	*
14	* Permission to use, copy, modify, and distribute this software and its
15	* documentation for any purpose and without fee is hereby granted,
16	* provided that the above copyright notice appear in all copies and that
17	* both that copyright notice and this permission notice appear in
18	* supporting documentation.
19	*
20	* This file is provided AS IS with no warranties of any kind. The author
21	* shall have no liability with respect to the infringement of copyrights,
22	* trade secrets or any patents by this file or any part thereof. In no
23	* event will the author be liable for any lost revenue or profits or
24	* other special, indirect and consequential damages.
25	*
26	* Revision History:
27	* 01-Nov-2000: Allocation checks
28	* 10-May-1997: Jamie Zawinski <jwz@jwz.org> compatible with xscreensaver
29	* 01-Sep-1995: color knotted components differently, J. Neil.
30	* 29-Aug-1995: Written. John Neil <neil@math.idbsu.edu>
31	*/
32
33	#ifdef STANDALONE
34	#define MODE_braid
35	#define PROGCLASS "Braid"
36	#define HACK_INIT init_braid
37	#define HACK_DRAW draw_braid
38	#define braid_opts xlockmore_opts
39	#define DEFAULTS "*delay: 1000 \n" \
40	"*count: 15 \n" \
41	"*cycles: 100 \n" \
42	"*size: -7 \n" \
43	"*ncolors: 64 \n"
44	#define UNIFORM_COLORS
45	#include "xlockmore.h"
46	#include "erase.h"
47	#else /* STANDALONE */
48	#include "xlock.h"
49
50	#endif /* STANDALONE */
51
52	#ifdef MODE_braid
53
54	ModeSpecOpt braid_opts =
55	{0, (XrmOptionDescRec ) NULL, 0, (argtype ) NULL, (OptionStruct *) NULL};
56
57	#ifdef USE_MODULES
58	ModStruct braid_description =
59	{"braid", "init_braid", "draw_braid", "release_braid",
60	"refresh_braid", "init_braid", (char *) NULL, &braid_opts,
61	1000, 15, 100, 1, 64, 1.0, "",
62	"Shows random braids and knots", 0, NULL};
63
64	#endif
65
66	#if defined( COLORROUND ) && defined( COLORCOMP )
67	#undef COLORROUND
68	#undef COLORCOMP
69	#endif
70
71	#if !defined( COLORROUND ) && !defined( COLORCOMP )
72	#if 0
73	/* to color in a circular pattern use COLORROUND */
74	#define COLORROUND
75	#else
76	/* to color by component use COLORCOMP */
77	#define COLORCOMP
78	#endif
79	#endif
80
81	#define MAXLENGTH 50 /* the maximum length of a braid word */
82	#define MINLENGTH 8 /* the minimum length of a braid word */
83	#define MAXSTRANDS 15 /* the maximum number of strands in the braid */
84	#define MINSTRANDS 3 /* the minimum number of strands in the braid */
85	#define SPINRATE 12.0 /* the rate at which the colors spin */
86
87	#define INTRAND(min,max) (NRAND((max+1)-(min))+(min))
88	#define FLOATRAND(min,max) ((min)+((double) LRAND()/((double) MAXRAND))*((max)-(min)))
89
90	typedef struct {
91	int linewidth;
92	int braidword[MAXLENGTH];
93	int components[MAXSTRANDS];
94	int startcomp[MAXLENGTH][MAXSTRANDS];
95	int nstrands;
96	int braidlength;
97	float startcolor;
98	int center_x;
99	int center_y;
100	float min_radius;
101	float max_radius;
102	float top, bottom, left, right;
103	int age;
104	int color_direction;
105	} braidtype;
106
107	static braidtype braids = (braidtype ) NULL;
108
109	static int
110	applyword(braidtype * braid, int string, int position)
111	{
112	int i, c;
113
114	c = string;
115	for (i = position; i < braid->braidlength; i++) {
116	if (c == ABS(braid->braidword[i]))
117	c--;
118	else if (c == ABS(braid->braidword[i]) - 1)
119	c++;
120	}
121	for (i = 0; i < position; i++) {
122	if (c == ABS(braid->braidword[i]))
123	c--;
124	else if (c == ABS(braid->braidword[i]) - 1)
125	c++;
126	}
127	return c;
128	}
129
130	#if 0
131	static int
132	applywordto(braidtype * braid, int string, int position)
133	{
134	int i, c;
135
136	c = string;
137	for (i = 0; i < position; i++) {
138	if (c == ABS(braid->braidword[i])) {
139	c--;
140	} else if (c == ABS(braid->braidword[i]) - 1) {
141	c++;
142	}
143	}
144	return c;
145	}
146	#endif
147
148	static int
149	applywordbackto(braidtype * braid, int string, int position)
150	{
151	int i, c;
152
153	c = string;
154	for (i = position - 1; i >= 0; i--) {
155	if (c == ABS(braid->braidword[i])) {
156	c--;
157	} else if (c == ABS(braid->braidword[i]) - 1) {
158	c++;
159	}
160	}
161	return c;
162	}
163
164	void
165	init_braid(ModeInfo * mi)
166	{
167	braidtype *braid;
168	int used[MAXSTRANDS];
169	int i, count, comp, c;
170	float min_length;
171
172	if (braids == NULL) {
173	if ((braids = (braidtype *) calloc(MI_NUM_SCREENS(mi),
174	sizeof (braidtype))) == NULL)
175	return;
176	}
177	braid = &braids[MI_SCREEN(mi)];
178
179	braid->center_x = MI_WIDTH(mi) / 2;
180	braid->center_y = MI_HEIGHT(mi) / 2;
181	braid->age = 0;
182
183	/* jwz: go in the other direction sometimes. */
184	braid->color_direction = ((LRAND() & 1) ? 1 : -1);
185
186	MI_CLEARWINDOW(mi);
187
188	min_length = (braid->center_x > braid->center_y) ?
189	braid->center_y : braid->center_x;
190	braid->min_radius = min_length * 0.30;
191	braid->max_radius = min_length * 0.90;
192
193	if (MI_COUNT(mi) < MINSTRANDS)
194	braid->nstrands = MINSTRANDS;
195	else
196	braid->nstrands = INTRAND(MINSTRANDS,
197	MAX(MIN(MIN(MAXSTRANDS, MI_COUNT(mi)),
198	(int) ((braid->max_radius - braid->min_radius) / 5.0)), MINSTRANDS));
199	braid->braidlength = INTRAND(MINLENGTH, MIN(MAXLENGTH, braid->nstrands * 6));
200
201	for (i = 0; i < braid->braidlength; i++) {
202	braid->braidword[i] =
203	INTRAND(1, braid->nstrands - 1) * (INTRAND(1, 2) * 2 - 3);
204	if (i > 0)
205	while (braid->braidword[i] == -braid->braidword[i - 1])
206	braid->braidword[i] = INTRAND(1, braid->nstrands - 1) * (INTRAND(1, 2) * 2 - 3);
207	}
208
209	while (braid->braidword[0] == -braid->braidword[braid->braidlength - 1])
210	braid->braidword[braid->braidlength - 1] =
211	INTRAND(1, braid->nstrands - 1) * (INTRAND(1, 2) * 2 - 3);
212
213	do {
214	(void) memset((char *) used, 0, sizeof (used));
215	count = 0;
216	for (i = 0; i < braid->braidlength; i++)
217	used[ABS(braid->braidword[i])]++;
218	for (i = 0; i < braid->nstrands; i++)
219	count += (used[i] > 0) ? 1 : 0;
220	if (count < braid->nstrands - 1) {
221	braid->braidword[braid->braidlength] =
222	INTRAND(1, braid->nstrands - 1) * (INTRAND(1, 2) * 2 - 3);
223	while (braid->braidword[braid->braidlength] ==
224	-braid->braidword[braid->braidlength - 1] &&
225	braid->braidword[0] == -braid->braidword[braid->braidlength])
226	braid->braidword[braid->braidlength] =
227	INTRAND(1, braid->nstrands - 1) * (INTRAND(1, 2) * 2 - 3);
228	braid->braidlength++;
229	}
230	} while (count < braid->nstrands - 1 && braid->braidlength < MAXLENGTH);
231
232	braid->startcolor = (MI_NPIXELS(mi) > 2) ?
233	(float) NRAND(MI_NPIXELS(mi)) : 0.0;
234	/* XSetLineAttributes (display, MI_GC(mi), 2, LineSolid, CapRound,
235	JoinRound); */
236
237	(void) memset((char *) braid->components, 0, sizeof (braid->components));
238	c = 1;
239	comp = 0;
240	braid->components[0] = 1;
241	do {
242	i = comp;
243	do {
244	i = applyword(braid, i, 0);
245	braid->components[i] = braid->components[comp];
246	} while (i != comp);
247	count = 0;
248	for (i = 0; i < braid->nstrands; i++)
249	if (braid->components[i] == 0)
250	count++;
251	if (count > 0) {
252	for (comp = 0; braid->components[comp] != 0; comp++);
253	braid->components[comp] = ++c;
254	}
255	} while (count > 0);
256
257	braid->linewidth = MI_SIZE(mi);
258
259	if (braid->linewidth < 0)
260	braid->linewidth = NRAND(-braid->linewidth) + 1;
261	if (braid->linewidth * braid->linewidth * 8 > MIN(MI_WIDTH(mi), MI_HEIGHT(mi)))
262	braid->linewidth = MIN(1, (int) sqrt((double) MIN(MI_WIDTH(mi), MI_HEIGHT(mi)) / 8));
263	for (i = 0; i < braid->nstrands; i++)
264	if (!(braid->components[i] & 1))
265	braid->components[i] *= -1;
266	}
267
268	void
269	draw_braid(ModeInfo * mi)
270	{
271	Display *display = MI_DISPLAY(mi);
272	Window window = MI_WINDOW(mi);
273	int num_points = 500;
274	float t_inc;
275	float theta, psi;
276	float t, r_diff;
277	int i, s;
278	float x_1, y_1, x_2, y_2, r1, r2;
279	float color, color_use = 0.0, color_inc;
280	braidtype *braid;
281
282	if (braids == NULL)
283	return;
284	braid = &braids[MI_SCREEN(mi)];
285
286	MI_IS_DRAWN(mi) = True;
287	XSetLineAttributes(display, MI_GC(mi), braid->linewidth,
288	LineSolid,
289	(braid->linewidth <= 3 ? CapButt : CapRound),
290	JoinMiter);
291
292	theta = (2.0 * M_PI) / (float) (braid->braidlength);
293	t_inc = (2.0 * M_PI) / (float) num_points;
294	color_inc = (float) MI_NPIXELS(mi) * braid->color_direction /
295	(float) num_points;
296	braid->startcolor += SPINRATE * color_inc;
297	if (((int) braid->startcolor) >= MI_NPIXELS(mi))
298	braid->startcolor = 0.0;
299
300	r_diff = (braid->max_radius - braid->min_radius) / (float) (braid->nstrands);
301
302	color = braid->startcolor;
303	psi = 0.0;
304	for (i = 0; i < braid->braidlength; i++) {
305	psi += theta;
306	for (t = 0.0; t < theta; t += t_inc) {
307	#ifdef COLORROUND
308	color += color_inc;
309	if (((int) color) >= MI_NPIXELS(mi))
310	color = 0.0;
311	color_use = color;
312	#endif
313	for (s = 0; s < braid->nstrands; s++) {
314	if (ABS(braid->braidword[i]) == s)
315	continue;
316	if (ABS(braid->braidword[i]) - 1 == s) {
317	/* crosSINFg */
318	#ifdef COLORCOMP
319	if (MI_NPIXELS(mi) > 2) {
320	color_use = color + SPINRATE *
321	braid->components[applywordbackto(braid, s, i)] +
322	(psi + t) / 2.0 / M_PI * (float) MI_NPIXELS(mi);
323	while (((int) color_use) >= MI_NPIXELS(mi))
324	color_use -= (float) MI_NPIXELS(mi);
325	while (((int) color_use) < 0)
326	color_use += (float) MI_NPIXELS(mi);
327	}
328	#endif
329	#ifdef COLORROUND
330	if (MI_NPIXELS(mi) > 2) {
331	color_use += SPINRATE * color_inc;
332	while (((int) color_use) >= MI_NPIXELS(mi))
333	color_use -= (float) MI_NPIXELS(mi);
334	}
335	#endif
336	r1 = braid->min_radius + r_diff * (float) (s);
337	r2 = braid->min_radius + r_diff * (float) (s + 1);
338	if (braid->braidword[i] > 0 \|\|
339	(FABSF(t - theta / 2.0) > theta / 7.0)) {
340	x_1 = ((0.5 * (1.0 + SINF(t / theta * M_PI - M_PI_2)) * r2 +
341	0.5 * (1.0 + SINF((theta - t) / theta * M_PI - M_PI_2)) * r1)) *
342	COSF(t + psi) + braid->center_x;
343	y_1 = ((0.5 * (1.0 + SINF(t / theta * M_PI - M_PI_2)) * r2 +
344	0.5 * (1.0 + SINF((theta - t) / theta * M_PI - M_PI_2)) * r1)) *
345	SINF(t + psi) + braid->center_y;
346	x_2 = ((0.5 * (1.0 + SINF((t + t_inc) / theta * M_PI - M_PI_2)) * r2 +
347	0.5 * (1.0 + SINF((theta - t - t_inc) / theta * M_PI - M_PI_2)) * r1)) *
348	COSF(t + t_inc + psi) + braid->center_x;
349	y_2 = ((0.5 * (1.0 + SINF((t + t_inc) / theta * M_PI - M_PI_2)) * r2 +
350	0.5 * (1.0 + SINF((theta - t - t_inc) / theta * M_PI - M_PI_2)) * r1)) *
351	SINF(t + t_inc + psi) + braid->center_y;
352	if (MI_NPIXELS(mi) > 2)
353	XSetForeground(display, MI_GC(mi), MI_PIXEL(mi, (int) color_use));
354	else
355	XSetForeground(display, MI_GC(mi), MI_WHITE_PIXEL(mi));
356
357	XDrawLine(display, window, MI_GC(mi),
358	(int) (x_1), (int) (y_1), (int) (x_2), (int) (y_2));
359	}
360	#ifdef COLORCOMP
361	if (MI_NPIXELS(mi) > 2) {
362	color_use = color + SPINRATE *
363	braid->components[applywordbackto(braid, s + 1, i)] +
364	(psi + t) / 2.0 / M_PI * (float) MI_NPIXELS(mi);
365	while (((int) color_use) >= MI_NPIXELS(mi))
366	color_use -= (float) MI_NPIXELS(mi);
367	while (((int) color_use) < 0)
368	color_use += (float) MI_NPIXELS(mi);
369	}
370	#endif
371	if (braid->braidword[i] < 0 \|\|
372	(FABSF(t - theta / 2.0) > theta / 7.0)) {
373	x_1 = ((0.5 * (1.0 + SINF(t / theta * M_PI - M_PI_2)) * r1 +
374	0.5 * (1.0 + SINF((theta - t) / theta * M_PI - M_PI_2)) * r2)) *
375	COSF(t + psi) + braid->center_x;
376	y_1 = ((0.5 * (1.0 + SINF(t / theta * M_PI - M_PI_2)) * r1 +
377	0.5 * (1.0 + SINF((theta - t) / theta * M_PI - M_PI_2)) * r2)) *
378	SINF(t + psi) + braid->center_y;
379	x_2 = ((0.5 * (1.0 + SINF((t + t_inc) / theta * M_PI - M_PI_2)) * r1 +
380	0.5 * (1.0 + SINF((theta - t - t_inc) / theta * M_PI - M_PI_2)) * r2)) *
381	COSF(t + t_inc + psi) + braid->center_x;
382	y_2 = ((0.5 * (1.0 + SINF((t + t_inc) / theta * M_PI - M_PI_2)) * r1 +
383	0.5 * (1.0 + SINF((theta - t - t_inc) / theta * M_PI - M_PI_2)) * r2)) *
384	SINF(t + t_inc + psi) + braid->center_y;
385	if (MI_NPIXELS(mi) > 2)
386	XSetForeground(display, MI_GC(mi), MI_PIXEL(mi, (int) color_use));
387	else
388	XSetForeground(display, MI_GC(mi), MI_WHITE_PIXEL(mi));
389
390	XDrawLine(display, window, MI_GC(mi),
391	(int) (x_1), (int) (y_1), (int) (x_2), (int) (y_2));
392	}
393	} else {
394	/* no crosSINFg */
395	#ifdef COLORCOMP
396	if (MI_NPIXELS(mi) > 2) {
397	color_use = color + SPINRATE *
398	braid->components[applywordbackto(braid, s, i)] +
399	(psi + t) / 2.0 / M_PI * (float) MI_NPIXELS(mi);
400	while (((int) color_use) >= MI_NPIXELS(mi))
401	color_use -= (float) MI_NPIXELS(mi);
402	while (((int) color_use) < 0)
403	color_use += (float) MI_NPIXELS(mi);
404	}
405	#endif
406	#ifdef COLORROUND
407	if (MI_NPIXELS(mi) > 2) {
408	color_use += SPINRATE * color_inc;
409	while (((int) color_use) >= MI_NPIXELS(mi))
410	color_use -= (float) MI_NPIXELS(mi);
411	}
412	#endif
413	r1 = braid->min_radius + r_diff * (float) (s);
414	x_1 = r1 * COSF(t + psi) + braid->center_x;
415	y_1 = r1 * SINF(t + psi) + braid->center_y;
416	x_2 = r1 * COSF(t + t_inc + psi) + braid->center_x;
417	y_2 = r1 * SINF(t + t_inc + psi) + braid->center_y;
418	if (MI_NPIXELS(mi) > 2)
419	XSetForeground(display, MI_GC(mi), MI_PIXEL(mi, (int) color_use));
420	else
421	XSetForeground(display, MI_GC(mi), MI_WHITE_PIXEL(mi));
422
423	XDrawLine(display, window, MI_GC(mi),
424	(int) (x_1), (int) (y_1), (int) (x_2), (int) (y_2));
425	}
426	}
427	}
428	}
429	XSetLineAttributes(display, MI_GC(mi), 1, LineSolid, CapNotLast, JoinRound);
430
431	if (++braid->age > MI_CYCLES(mi)) {
432	#ifdef STANDALONE
433	erase_full_window(MI_DISPLAY(mi), MI_WINDOW(mi));
434	#endif
435	init_braid(mi);
436	}
437	}
438
439	void
440	release_braid(ModeInfo * mi)
441	{
442	if (braids != NULL) {
443	(void) free((void *) braids);
444	braids = (braidtype *) NULL;
445	}
446	}
447
448	void
449	refresh_braid(ModeInfo * mi)
450	{
451	MI_CLEARWINDOW(mi);
452	}
453
454	#endif /* MODE_braid */

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