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Diffstat (limited to 'hacks/braid.c')
-rw-r--r-- | hacks/braid.c | 443 |
1 files changed, 443 insertions, 0 deletions
diff --git a/hacks/braid.c b/hacks/braid.c new file mode 100644 index 0000000..4f5a77c --- /dev/null +++ b/hacks/braid.c @@ -0,0 +1,443 @@ +/* -*- Mode: C; tab-width: 4 -*- */ +/*- + * braid --- random braids around a circle and then changes the color in + * a rotational pattern + */ + +#if 0 +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 DEFAULTS "*delay: 1000 \n" \ + "*count: 15 \n" \ + "*cycles: 100 \n" \ + "*size: -7 \n" \ + "*ncolors: 64 \n" \ + "*fpsSolid: true \n" \ + "*ignoreRotation: True" \ + +# define UNIFORM_COLORS +# define free_braid 0 +# define release_braid 0 +# define reshape_braid 0 +# define braid_handle_event 0 +# include "xlockmore.h" +#else /* STANDALONE */ +# include "xlock.h" +# define ENTRYPOINT /**/ +#endif /* STANDALONE */ + +#ifdef MODE_braid + +ENTRYPOINT ModeSpecOpt braid_opts = {0, NULL, 0, NULL, NULL}; + +#ifdef USE_MODULES +ModStruct braid_description = +{"braid", "init_braid", "draw_braid", (char *) NULL, + "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; +} + +ENTRYPOINT void +init_braid(ModeInfo * mi) +{ + braidtype *braid; + int used[MAXSTRANDS]; + int i, count, comp, c; + float min_length; + + MI_INIT (mi, braids); + 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 -1, 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; +} + +ENTRYPOINT 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); + } +} + +#ifndef STANDALONE +ENTRYPOINT void +refresh_braid(ModeInfo * mi) +{ + MI_CLEARWINDOW(mi); +} +#endif + +XSCREENSAVER_MODULE ("Braid", braid) + +#endif /* MODE_braid */ |