452 lines
14 KiB
C
452 lines
14 KiB
C
/* -*- Mode: C; tab-width: 4 -*- */
|
|
/*-
|
|
* braid --- random braids around a circle and then changes the color in
|
|
* a rotational pattern
|
|
*/
|
|
|
|
#if !defined( lint ) && !defined( SABER )
|
|
static const char sccsid[] = "@(#)braid.c 5.00 2000/11/01 xlockmore";
|
|
|
|
#endif
|
|
|
|
/*-
|
|
* Copyright (c) 1995 by John Neil.
|
|
*
|
|
* 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:
|
|
* 01-Nov-2000: Allocation checks
|
|
* 10-May-1997: Jamie Zawinski <jwz@jwz.org> compatible with xscreensaver
|
|
* 01-Sep-1995: color knotted components differently, J. Neil.
|
|
* 29-Aug-1995: Written. John Neil <neil@math.idbsu.edu>
|
|
*/
|
|
|
|
#ifdef STANDALONE
|
|
#define MODE_braid
|
|
#define PROGCLASS "Braid"
|
|
#define HACK_INIT init_braid
|
|
#define HACK_DRAW draw_braid
|
|
#define braid_opts xlockmore_opts
|
|
#define DEFAULTS "*delay: 1000 \n" \
|
|
"*count: 15 \n" \
|
|
"*cycles: 100 \n" \
|
|
"*size: -7 \n" \
|
|
"*ncolors: 64 \n"
|
|
#define UNIFORM_COLORS
|
|
#include "xlockmore.h"
|
|
#else /* STANDALONE */
|
|
#include "xlock.h"
|
|
|
|
#endif /* STANDALONE */
|
|
|
|
#ifdef MODE_braid
|
|
|
|
ModeSpecOpt braid_opts =
|
|
{0, (XrmOptionDescRec *) NULL, 0, (argtype *) NULL, (OptionStruct *) NULL};
|
|
|
|
#ifdef USE_MODULES
|
|
ModStruct braid_description =
|
|
{"braid", "init_braid", "draw_braid", "release_braid",
|
|
"refresh_braid", "init_braid", (char *) NULL, &braid_opts,
|
|
1000, 15, 100, 1, 64, 1.0, "",
|
|
"Shows random braids and knots", 0, NULL};
|
|
|
|
#endif
|
|
|
|
#if defined( COLORROUND ) && defined( COLORCOMP )
|
|
#undef COLORROUND
|
|
#undef COLORCOMP
|
|
#endif
|
|
|
|
#if !defined( COLORROUND ) && !defined( COLORCOMP )
|
|
#if 0
|
|
/* to color in a circular pattern use COLORROUND */
|
|
#define COLORROUND
|
|
#else
|
|
/* to color by component use COLORCOMP */
|
|
#define COLORCOMP
|
|
#endif
|
|
#endif
|
|
|
|
#define MAXLENGTH 50 /* the maximum length of a braid word */
|
|
#define MINLENGTH 8 /* the minimum length of a braid word */
|
|
#define MAXSTRANDS 15 /* the maximum number of strands in the braid */
|
|
#define MINSTRANDS 3 /* the minimum number of strands in the braid */
|
|
#define SPINRATE 12.0 /* the rate at which the colors spin */
|
|
|
|
#define INTRAND(min,max) (NRAND((max+1)-(min))+(min))
|
|
#define FLOATRAND(min,max) ((min)+((double) LRAND()/((double) MAXRAND))*((max)-(min)))
|
|
|
|
typedef struct {
|
|
int linewidth;
|
|
int braidword[MAXLENGTH];
|
|
int components[MAXSTRANDS];
|
|
int startcomp[MAXLENGTH][MAXSTRANDS];
|
|
int nstrands;
|
|
int braidlength;
|
|
float startcolor;
|
|
int center_x;
|
|
int center_y;
|
|
float min_radius;
|
|
float max_radius;
|
|
float top, bottom, left, right;
|
|
int age;
|
|
int color_direction;
|
|
} braidtype;
|
|
|
|
static braidtype *braids = (braidtype *) NULL;
|
|
|
|
static int
|
|
applyword(braidtype * braid, int string, int position)
|
|
{
|
|
int i, c;
|
|
|
|
c = string;
|
|
for (i = position; i < braid->braidlength; i++) {
|
|
if (c == ABS(braid->braidword[i]))
|
|
c--;
|
|
else if (c == ABS(braid->braidword[i]) - 1)
|
|
c++;
|
|
}
|
|
for (i = 0; i < position; i++) {
|
|
if (c == ABS(braid->braidword[i]))
|
|
c--;
|
|
else if (c == ABS(braid->braidword[i]) - 1)
|
|
c++;
|
|
}
|
|
return c;
|
|
}
|
|
|
|
#if 0
|
|
static int
|
|
applywordto(braidtype * braid, int string, int position)
|
|
{
|
|
int i, c;
|
|
|
|
c = string;
|
|
for (i = 0; i < position; i++) {
|
|
if (c == ABS(braid->braidword[i])) {
|
|
c--;
|
|
} else if (c == ABS(braid->braidword[i]) - 1) {
|
|
c++;
|
|
}
|
|
}
|
|
return c;
|
|
}
|
|
#endif
|
|
|
|
static int
|
|
applywordbackto(braidtype * braid, int string, int position)
|
|
{
|
|
int i, c;
|
|
|
|
c = string;
|
|
for (i = position - 1; i >= 0; i--) {
|
|
if (c == ABS(braid->braidword[i])) {
|
|
c--;
|
|
} else if (c == ABS(braid->braidword[i]) - 1) {
|
|
c++;
|
|
}
|
|
}
|
|
return c;
|
|
}
|
|
|
|
void
|
|
init_braid(ModeInfo * mi)
|
|
{
|
|
braidtype *braid;
|
|
int used[MAXSTRANDS];
|
|
int i, count, comp, c;
|
|
float min_length;
|
|
|
|
if (braids == NULL) {
|
|
if ((braids = (braidtype *) calloc(MI_NUM_SCREENS(mi),
|
|
sizeof (braidtype))) == NULL)
|
|
return;
|
|
}
|
|
braid = &braids[MI_SCREEN(mi)];
|
|
|
|
braid->center_x = MI_WIDTH(mi) / 2;
|
|
braid->center_y = MI_HEIGHT(mi) / 2;
|
|
braid->age = 0;
|
|
|
|
/* jwz: go in the other direction sometimes. */
|
|
braid->color_direction = ((LRAND() & 1) ? 1 : -1);
|
|
|
|
MI_CLEARWINDOW(mi);
|
|
|
|
min_length = (braid->center_x > braid->center_y) ?
|
|
braid->center_y : braid->center_x;
|
|
braid->min_radius = min_length * 0.30;
|
|
braid->max_radius = min_length * 0.90;
|
|
|
|
if (MI_COUNT(mi) < MINSTRANDS)
|
|
braid->nstrands = MINSTRANDS;
|
|
else
|
|
braid->nstrands = INTRAND(MINSTRANDS,
|
|
MAX(MIN(MIN(MAXSTRANDS, MI_COUNT(mi)),
|
|
(int) ((braid->max_radius - braid->min_radius) / 5.0)), MINSTRANDS));
|
|
braid->braidlength = INTRAND(MINLENGTH, MIN(MAXLENGTH, braid->nstrands * 6));
|
|
|
|
for (i = 0; i < braid->braidlength; i++) {
|
|
braid->braidword[i] =
|
|
INTRAND(1, braid->nstrands - 1) * (INTRAND(1, 2) * 2 - 3);
|
|
if (i > 0)
|
|
while (braid->braidword[i] == -braid->braidword[i - 1])
|
|
braid->braidword[i] = INTRAND(1, braid->nstrands - 1) * (INTRAND(1, 2) * 2 - 3);
|
|
}
|
|
|
|
while (braid->braidword[0] == -braid->braidword[braid->braidlength - 1])
|
|
braid->braidword[braid->braidlength - 1] =
|
|
INTRAND(1, braid->nstrands - 1) * (INTRAND(1, 2) * 2 - 3);
|
|
|
|
do {
|
|
(void) memset((char *) used, 0, sizeof (used));
|
|
count = 0;
|
|
for (i = 0; i < braid->braidlength; i++)
|
|
used[ABS(braid->braidword[i])]++;
|
|
for (i = 0; i < braid->nstrands; i++)
|
|
count += (used[i] > 0) ? 1 : 0;
|
|
if (count < braid->nstrands - 1) {
|
|
braid->braidword[braid->braidlength] =
|
|
INTRAND(1, braid->nstrands - 1) * (INTRAND(1, 2) * 2 - 3);
|
|
while (braid->braidword[braid->braidlength] ==
|
|
-braid->braidword[braid->braidlength - 1] &&
|
|
braid->braidword[0] == -braid->braidword[braid->braidlength])
|
|
braid->braidword[braid->braidlength] =
|
|
INTRAND(1, braid->nstrands - 1) * (INTRAND(1, 2) * 2 - 3);
|
|
braid->braidlength++;
|
|
}
|
|
} while (count < braid->nstrands - 1 && braid->braidlength < MAXLENGTH);
|
|
|
|
braid->startcolor = (MI_NPIXELS(mi) > 2) ?
|
|
(float) NRAND(MI_NPIXELS(mi)) : 0.0;
|
|
/* XSetLineAttributes (display, MI_GC(mi), 2, LineSolid, CapRound,
|
|
JoinRound); */
|
|
|
|
(void) memset((char *) braid->components, 0, sizeof (braid->components));
|
|
c = 1;
|
|
comp = 0;
|
|
braid->components[0] = 1;
|
|
do {
|
|
i = comp;
|
|
do {
|
|
i = applyword(braid, i, 0);
|
|
braid->components[i] = braid->components[comp];
|
|
} while (i != comp);
|
|
count = 0;
|
|
for (i = 0; i < braid->nstrands; i++)
|
|
if (braid->components[i] == 0)
|
|
count++;
|
|
if (count > 0) {
|
|
for (comp = 0; braid->components[comp] != 0; comp++);
|
|
braid->components[comp] = ++c;
|
|
}
|
|
} while (count > 0);
|
|
|
|
braid->linewidth = MI_SIZE(mi);
|
|
|
|
if (braid->linewidth < 0)
|
|
braid->linewidth = NRAND(-braid->linewidth) + 1;
|
|
if (braid->linewidth * braid->linewidth * 8 > MIN(MI_WIDTH(mi), MI_HEIGHT(mi)))
|
|
braid->linewidth = MIN(1, (int) sqrt((double) MIN(MI_WIDTH(mi), MI_HEIGHT(mi)) / 8));
|
|
for (i = 0; i < braid->nstrands; i++)
|
|
if (!(braid->components[i] & 1))
|
|
braid->components[i] *= -1;
|
|
}
|
|
|
|
void
|
|
draw_braid(ModeInfo * mi)
|
|
{
|
|
Display *display = MI_DISPLAY(mi);
|
|
Window window = MI_WINDOW(mi);
|
|
int num_points = 500;
|
|
float t_inc;
|
|
float theta, psi;
|
|
float t, r_diff;
|
|
int i, s;
|
|
float x_1, y_1, x_2, y_2, r1, r2;
|
|
float color, color_use = 0.0, color_inc;
|
|
braidtype *braid;
|
|
|
|
if (braids == NULL)
|
|
return;
|
|
braid = &braids[MI_SCREEN(mi)];
|
|
|
|
MI_IS_DRAWN(mi) = True;
|
|
XSetLineAttributes(display, MI_GC(mi), braid->linewidth,
|
|
LineSolid,
|
|
(braid->linewidth <= 3 ? CapButt : CapRound),
|
|
JoinMiter);
|
|
|
|
theta = (2.0 * M_PI) / (float) (braid->braidlength);
|
|
t_inc = (2.0 * M_PI) / (float) num_points;
|
|
color_inc = (float) MI_NPIXELS(mi) * braid->color_direction /
|
|
(float) num_points;
|
|
braid->startcolor += SPINRATE * color_inc;
|
|
if (((int) braid->startcolor) >= MI_NPIXELS(mi))
|
|
braid->startcolor = 0.0;
|
|
|
|
r_diff = (braid->max_radius - braid->min_radius) / (float) (braid->nstrands);
|
|
|
|
color = braid->startcolor;
|
|
psi = 0.0;
|
|
for (i = 0; i < braid->braidlength; i++) {
|
|
psi += theta;
|
|
for (t = 0.0; t < theta; t += t_inc) {
|
|
#ifdef COLORROUND
|
|
color += color_inc;
|
|
if (((int) color) >= MI_NPIXELS(mi))
|
|
color = 0.0;
|
|
color_use = color;
|
|
#endif
|
|
for (s = 0; s < braid->nstrands; s++) {
|
|
if (ABS(braid->braidword[i]) == s)
|
|
continue;
|
|
if (ABS(braid->braidword[i]) - 1 == s) {
|
|
/* crosSINFg */
|
|
#ifdef COLORCOMP
|
|
if (MI_NPIXELS(mi) > 2) {
|
|
color_use = color + SPINRATE *
|
|
braid->components[applywordbackto(braid, s, i)] +
|
|
(psi + t) / 2.0 / M_PI * (float) MI_NPIXELS(mi);
|
|
while (((int) color_use) >= MI_NPIXELS(mi))
|
|
color_use -= (float) MI_NPIXELS(mi);
|
|
while (((int) color_use) < 0)
|
|
color_use += (float) MI_NPIXELS(mi);
|
|
}
|
|
#endif
|
|
#ifdef COLORROUND
|
|
if (MI_NPIXELS(mi) > 2) {
|
|
color_use += SPINRATE * color_inc;
|
|
while (((int) color_use) >= MI_NPIXELS(mi))
|
|
color_use -= (float) MI_NPIXELS(mi);
|
|
}
|
|
#endif
|
|
r1 = braid->min_radius + r_diff * (float) (s);
|
|
r2 = braid->min_radius + r_diff * (float) (s + 1);
|
|
if (braid->braidword[i] > 0 ||
|
|
(FABSF(t - theta / 2.0) > theta / 7.0)) {
|
|
x_1 = ((0.5 * (1.0 + SINF(t / theta * M_PI - M_PI_2)) * r2 +
|
|
0.5 * (1.0 + SINF((theta - t) / theta * M_PI - M_PI_2)) * r1)) *
|
|
COSF(t + psi) + braid->center_x;
|
|
y_1 = ((0.5 * (1.0 + SINF(t / theta * M_PI - M_PI_2)) * r2 +
|
|
0.5 * (1.0 + SINF((theta - t) / theta * M_PI - M_PI_2)) * r1)) *
|
|
SINF(t + psi) + braid->center_y;
|
|
x_2 = ((0.5 * (1.0 + SINF((t + t_inc) / theta * M_PI - M_PI_2)) * r2 +
|
|
0.5 * (1.0 + SINF((theta - t - t_inc) / theta * M_PI - M_PI_2)) * r1)) *
|
|
COSF(t + t_inc + psi) + braid->center_x;
|
|
y_2 = ((0.5 * (1.0 + SINF((t + t_inc) / theta * M_PI - M_PI_2)) * r2 +
|
|
0.5 * (1.0 + SINF((theta - t - t_inc) / theta * M_PI - M_PI_2)) * r1)) *
|
|
SINF(t + t_inc + psi) + braid->center_y;
|
|
if (MI_NPIXELS(mi) > 2)
|
|
XSetForeground(display, MI_GC(mi), MI_PIXEL(mi, (int) color_use));
|
|
else
|
|
XSetForeground(display, MI_GC(mi), MI_WHITE_PIXEL(mi));
|
|
|
|
XDrawLine(display, window, MI_GC(mi),
|
|
(int) (x_1), (int) (y_1), (int) (x_2), (int) (y_2));
|
|
}
|
|
#ifdef COLORCOMP
|
|
if (MI_NPIXELS(mi) > 2) {
|
|
color_use = color + SPINRATE *
|
|
braid->components[applywordbackto(braid, s + 1, i)] +
|
|
(psi + t) / 2.0 / M_PI * (float) MI_NPIXELS(mi);
|
|
while (((int) color_use) >= MI_NPIXELS(mi))
|
|
color_use -= (float) MI_NPIXELS(mi);
|
|
while (((int) color_use) < 0)
|
|
color_use += (float) MI_NPIXELS(mi);
|
|
}
|
|
#endif
|
|
if (braid->braidword[i] < 0 ||
|
|
(FABSF(t - theta / 2.0) > theta / 7.0)) {
|
|
x_1 = ((0.5 * (1.0 + SINF(t / theta * M_PI - M_PI_2)) * r1 +
|
|
0.5 * (1.0 + SINF((theta - t) / theta * M_PI - M_PI_2)) * r2)) *
|
|
COSF(t + psi) + braid->center_x;
|
|
y_1 = ((0.5 * (1.0 + SINF(t / theta * M_PI - M_PI_2)) * r1 +
|
|
0.5 * (1.0 + SINF((theta - t) / theta * M_PI - M_PI_2)) * r2)) *
|
|
SINF(t + psi) + braid->center_y;
|
|
x_2 = ((0.5 * (1.0 + SINF((t + t_inc) / theta * M_PI - M_PI_2)) * r1 +
|
|
0.5 * (1.0 + SINF((theta - t - t_inc) / theta * M_PI - M_PI_2)) * r2)) *
|
|
COSF(t + t_inc + psi) + braid->center_x;
|
|
y_2 = ((0.5 * (1.0 + SINF((t + t_inc) / theta * M_PI - M_PI_2)) * r1 +
|
|
0.5 * (1.0 + SINF((theta - t - t_inc) / theta * M_PI - M_PI_2)) * r2)) *
|
|
SINF(t + t_inc + psi) + braid->center_y;
|
|
if (MI_NPIXELS(mi) > 2)
|
|
XSetForeground(display, MI_GC(mi), MI_PIXEL(mi, (int) color_use));
|
|
else
|
|
XSetForeground(display, MI_GC(mi), MI_WHITE_PIXEL(mi));
|
|
|
|
XDrawLine(display, window, MI_GC(mi),
|
|
(int) (x_1), (int) (y_1), (int) (x_2), (int) (y_2));
|
|
}
|
|
} else {
|
|
/* no crosSINFg */
|
|
#ifdef COLORCOMP
|
|
if (MI_NPIXELS(mi) > 2) {
|
|
color_use = color + SPINRATE *
|
|
braid->components[applywordbackto(braid, s, i)] +
|
|
(psi + t) / 2.0 / M_PI * (float) MI_NPIXELS(mi);
|
|
while (((int) color_use) >= MI_NPIXELS(mi))
|
|
color_use -= (float) MI_NPIXELS(mi);
|
|
while (((int) color_use) < 0)
|
|
color_use += (float) MI_NPIXELS(mi);
|
|
}
|
|
#endif
|
|
#ifdef COLORROUND
|
|
if (MI_NPIXELS(mi) > 2) {
|
|
color_use += SPINRATE * color_inc;
|
|
while (((int) color_use) >= MI_NPIXELS(mi))
|
|
color_use -= (float) MI_NPIXELS(mi);
|
|
}
|
|
#endif
|
|
r1 = braid->min_radius + r_diff * (float) (s);
|
|
x_1 = r1 * COSF(t + psi) + braid->center_x;
|
|
y_1 = r1 * SINF(t + psi) + braid->center_y;
|
|
x_2 = r1 * COSF(t + t_inc + psi) + braid->center_x;
|
|
y_2 = r1 * SINF(t + t_inc + psi) + braid->center_y;
|
|
if (MI_NPIXELS(mi) > 2)
|
|
XSetForeground(display, MI_GC(mi), MI_PIXEL(mi, (int) color_use));
|
|
else
|
|
XSetForeground(display, MI_GC(mi), MI_WHITE_PIXEL(mi));
|
|
|
|
XDrawLine(display, window, MI_GC(mi),
|
|
(int) (x_1), (int) (y_1), (int) (x_2), (int) (y_2));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
XSetLineAttributes(display, MI_GC(mi), 1, LineSolid, CapNotLast, JoinRound);
|
|
|
|
if (++braid->age > MI_CYCLES(mi)) {
|
|
init_braid(mi);
|
|
}
|
|
}
|
|
|
|
void
|
|
release_braid(ModeInfo * mi)
|
|
{
|
|
if (braids != NULL) {
|
|
free(braids);
|
|
braids = (braidtype *) NULL;
|
|
}
|
|
}
|
|
|
|
void
|
|
refresh_braid(ModeInfo * mi)
|
|
{
|
|
MI_CLEARWINDOW(mi);
|
|
}
|
|
|
|
#endif /* MODE_braid */
|