diff options
Diffstat (limited to 'hacks/epicycle.c')
| -rw-r--r-- | hacks/epicycle.c | 798 |
1 files changed, 0 insertions, 798 deletions
diff --git a/hacks/epicycle.c b/hacks/epicycle.c deleted file mode 100644 index a8a257c..0000000 --- a/hacks/epicycle.c +++ /dev/null @@ -1,798 +0,0 @@ -/* epicycle --- The motion of a body with epicycles, as in the pre-Copernican - * cosmologies. - * - * Copyright (c) 1998 James Youngman <jay@gnu.org> - * - * Permission to use, copy, modify, distribute, and sell this software and its - * documentation for any purpose is hereby granted without fee, provided that - * the above copyright notice appear in all copies and that both that - * copyright notice and this permission notice appear in supporting - * documentation. No representations are made about the suitability of this - * software for any purpose. It is provided "as is" without express or - * implied warranty. - */ - -/* Standard C headers; screenhack.h assumes that these have already - * been included if required -- for example, it defines M_PI if not - * already defined. - */ -#include <float.h> -#include <math.h> - - -#include "screenhack.h" -#include "erase.h" - -/* MIT-SHM headers omitted; this screenhack doesn't use it */ - - - -/*********************************************************/ -/******************** MAGIC CONSTANTS ********************/ -/*********************************************************/ -#define MIN_RADIUS (5) /* smallest allowable circle radius */ -#define FILL_PROPORTION (0.9) /* proportion of screen to fill by scaling. */ -/*********************************************************/ -/***************** END OF MAGIC CONSTANTS ****************/ -/*********************************************************/ - - - -#define FULLCIRCLE (2.0 * M_PI) /* radians in a circle. */ - - -/* Some of these resource values here are hand-tuned to give a - * pleasing variety of interesting shapes. These are not the only - * good settings, but you may find you need to change some as a group - * to get pleasing figures. - */ -static const char *epicycle_defaults [] = { - ".background: black", - ".foreground: white", - "*fpsSolid: true", - "*colors: 100", - "*color0: red", - "*delay: 20000", - "*holdtime: 2", - "*lineWidth: 4", - "*minCircles: 2", - "*maxCircles: 10", - "*minSpeed: 0.003", - "*maxSpeed: 0.005", - "*harmonics: 8", - "*timestep: 1.0", - "*timestepCoarseFactor: 1.0", /* no option for this resource. */ - "*divisorPoisson: 0.4", - "*sizeFactorMin: 1.05", - "*sizeFactorMax: 2.05", -#ifdef HAVE_MOBILE - "*ignoreRotation: True", -#endif - 0 -}; - -/* options passed to this program */ -static XrmOptionDescRec epicycle_options [] = { - { "-color0", ".color0", XrmoptionSepArg, 0 }, - { "-colors", ".colors", XrmoptionSepArg, 0 }, - { "-colours", ".colors", XrmoptionSepArg, 0 }, - { "-foreground", ".foreground", XrmoptionSepArg, 0 }, - { "-delay", ".delay", XrmoptionSepArg, 0 }, - { "-holdtime", ".holdtime", XrmoptionSepArg, 0 }, - { "-linewidth", ".lineWidth", XrmoptionSepArg, 0 }, - { "-min_circles", ".minCircles", XrmoptionSepArg, 0 }, - { "-max_circles", ".maxCircles", XrmoptionSepArg, 0 }, - { "-min_speed", ".minSpeed", XrmoptionSepArg, 0 }, - { "-max_speed", ".maxSpeed", XrmoptionSepArg, 0 }, - { "-harmonics", ".harmonics", XrmoptionSepArg, 0 }, - { "-timestep", ".timestep", XrmoptionSepArg, 0 }, - { "-divisor_poisson",".divisorPoisson",XrmoptionSepArg, 0 }, - { "-size_factor_min", ".sizeFactorMin", XrmoptionSepArg, 0 }, - { "-size_factor_max", ".sizeFactorMax", XrmoptionSepArg, 0 }, - { 0, 0, 0, 0 } -}; - - -/* Each circle is centred on a point on the rim of another circle. - */ -struct tagCircle -{ - long radius; /* in pixels */ - double w; /* position (radians ccw from x-axis) */ - double initial_w; /* starting position */ - double wdot; /* rotation rate (change in w per iteration) */ - int divisor; - - struct tagCircle *pchild; -}; -typedef struct tagCircle Circle; - - -struct tagBody /* a body that moves on a system of circles. */ -{ - int x_origin, y_origin; - int x, y; - int old_x, old_y; - int current_color; /* pixel index into colors[] */ - Circle *epicycles; /* system of circles on which it moves. */ - struct tagBody *next; /* next in list. */ -}; -typedef struct tagBody Body; - - -struct state { - Display *dpy; - Window window; - GC color0; - int width, height; - int x_offset, y_offset; - int unit_pixels; - unsigned long bg; - Colormap cmap; - int restart; - double wdot_max; - XColor *colors; - int ncolors; - int color_shift_pos; /* how far we are towards that. */ - double colour_cycle_rate; - int harmonics; - double divisorPoisson; - double sizeFactorMin; - double sizeFactorMax; - int minCircles; - int maxCircles; - - Bool done; - - long L; - double T, timestep, circle, timestep_coarse; - int delay; - int uncleared; - int holdtime; - int xmax, xmin, ymax, ymin; - Body *pb0; - double xtime; - eraser_state *eraser; -}; - - - -/* Determine the GCD of two numbers using Euclid's method. The other - * possible algorighm is Stein's method, but it's probably only going - * to be much faster on machines with no divide instruction, like the - * ARM and the Z80. The former is very fast anyway and the latter - * probably won't run X clients; in any case, this calculation is not - * the bulk of the computational expense of the program. I originally - * tried using Stein's method, but I wanted to remove the gotos. Not - * wanting to introduce possible bugs, I plumped for Euclid's method - * instead. Lastly, Euclid's algorithm is preferred to the - * generalisation for N inputs. - * - * See Knuth, section 4.5.2. - */ -static int -gcd(int u, int v) /* Euclid's Method */ -{ - /* If either operand of % is negative, the sign of the result is - * implementation-defined. See section 6.3.5 "Multiplicative - * Operators" of the ANSI C Standard (page 46 [LEFT HAND PAGE!] of - * "Annotated C Standard", Osborne, ISBN 0-07-881952-0). - */ - if (u < 0) u = -u; - if (v < 0) v = -v; - - while (0 != v) - { - int r; - r = u % v; - u = v; - v = r; - } - return u; -} - -/* Determine the Lowest Common Multiple of two integers, using - * Euclid's Proposition 34, as explained in Knuth's The Art of - * Computer Programming, Vol 2, section 4.5.2. - */ -static int -lcm(int u, int v) -{ - return u / gcd(u,v) * v; -} - -static long -random_radius(struct state *st, double scale) -{ - long r; - - r = frand(scale) * st->unit_pixels/2; /* for frand() see utils/yarandom.h */ - if (r < MIN_RADIUS) - r = MIN_RADIUS; - return r; -} - - -static long -random_divisor(struct state *st) -{ - int divisor = 1; - int sign; - - while (frand(1.0) < st->divisorPoisson && divisor <= st->harmonics) - { - ++divisor; - } - sign = (frand(1.0) < 0.5) ? +1 : -1; - return sign * divisor; -} - - -/* Construct a circle or die. - */ -static Circle * -new_circle(struct state *st, double scale) -{ - Circle *p = malloc(sizeof(Circle)); - - p->radius = random_radius(st, scale); - p->w = p->initial_w = 0.0; - p->divisor = random_divisor(st); - p->wdot = st->wdot_max / p->divisor; - p->pchild = NULL; - - return p; -} - -static void delete_circle(Circle *p) -{ - free(p); -} - -static void -delete_circle_chain(Circle *p) -{ - while (p) - { - Circle *q = p->pchild; - delete_circle(p); - p = q; - } -} - -static Circle * -new_circle_chain(struct state *st) -{ - Circle *head; - double scale = 1.0, factor; - int n; - - /* Parent circles are larger than their children by a factor of at - * least FACTOR_MIN and at most FACTOR_MAX. - */ - factor = st->sizeFactorMin + frand(st->sizeFactorMax - st->sizeFactorMin); - - /* There are between minCircles and maxCircles in each figure. - */ - if (st->maxCircles == st->minCircles) - n = st->minCircles; /* Avoid division by zero. */ - else - n = st->minCircles + random() % (st->maxCircles - st->minCircles); - - head = NULL; - while (n--) - { - Circle *p = new_circle(st, scale); - p->pchild = head; - head = p; - - scale /= factor; - } - return head; -} - -static void -assign_random_common_w(Circle *p) -{ - double w_common = frand(FULLCIRCLE); /* anywhere on the circle */ - while (p) - { - p->initial_w = w_common; - p = p->pchild; - } -} - -static Body * -new_body(struct state *st) -{ - Body *p = malloc(sizeof(Body)); - if (!p) abort(); - p->epicycles = new_circle_chain(st); - p->current_color = 0; /* ?? start them all on different colors? */ - p->next = NULL; - p->x = p->y = 0; - p->old_x = p->old_y = 0; - p->x_origin = p->y_origin = 0; - - /* Start all the epicycles at the same w value to make it easier to - * figure out at what T value the cycle is closed. We don't just fix - * the initial W value because that makes all the patterns tend to - * be symmetrical about the X axis. - */ - assign_random_common_w(p->epicycles); - return p; -} - -static void -delete_body(Body *p) -{ - delete_circle_chain(p->epicycles); - free(p); -} - - -static void -draw_body(struct state *st, Body *pb, GC gc) -{ - XDrawLine(st->dpy, st->window, gc, pb->old_x, pb->old_y, pb->x, pb->y); -} - -static long -compute_divisor_lcm(Circle *p) -{ - long l = 1; - - while (p) - { - l = lcm(l, p->divisor); - p = p->pchild; - } - return l; -} - - -/* move_body() - * - * Calculate the position for the body at time T. We work in double - * rather than int to avoid the cumulative errors that would be caused - * by the rounding implicit in an assignment to int. - */ -static void -move_body(Body *pb, double t) -{ - Circle *p; - double x, y; - - pb->old_x = pb->x; - pb->old_y = pb->y; - - x = pb->x_origin; - y = pb->y_origin; - - for (p=pb->epicycles; NULL != p; p=p->pchild) - { - /* angular pos = initial_pos + time * angular speed */ - /* but this is an angular position, so modulo FULLCIRCLE. */ - p->w = fmod(p->initial_w + (t * p->wdot), FULLCIRCLE); - - x += (p->radius * cos(p->w)); - y += (p->radius * sin(p->w)); - } - - pb->x = (int)x; - pb->y = (int)y; -} - -static int -colour_init(struct state *st, XWindowAttributes *pxgwa) -{ - XGCValues gcv; - -#if 0 - int H = random() % 360; /* colour choice from attraction.c. */ - double S1 = 0.25; - double S2 = 1.00; - double V = frand(0.25) + 0.75; - int line_width = 0; -#endif - - int retval = 1; - unsigned long valuemask = 0L; - unsigned long fg; - - /* Free any already allocated colors... - */ - if (st->colors) - { - free_colors(pxgwa->screen, st->cmap, st->colors, st->ncolors); - st->colors = 0; - st->ncolors = 0; - } - - st->ncolors = get_integer_resource (st->dpy, "colors", "Colors"); - if (0 == st->ncolors) /* English spelling? */ - st->ncolors = get_integer_resource (st->dpy, "colours", "Colors"); - - if (st->ncolors < 2) - st->ncolors = 2; - if (st->ncolors <= 2) - mono_p = True; - st->colors = 0; - - if (!mono_p) - { - st->colors = (XColor *) malloc(sizeof(*st->colors) * (st->ncolors+1)); - if (!st->colors) abort(); - - make_smooth_colormap (pxgwa->screen, pxgwa->visual, st->cmap, - st->colors, &st->ncolors, - True, /* allocate */ - False, /* not writable */ - True); /* verbose (complain about failure) */ - if (st->ncolors <= 2) - { - if (st->colors) - free (st->colors); - st->colors = 0; - mono_p = True; - } - } - - - st->bg = get_pixel_resource (st->dpy, st->cmap, "background", "Background"); - - /* Set the line width - */ - gcv.line_width = get_integer_resource (st->dpy, "lineWidth", "Integer"); - if (gcv.line_width) - { - valuemask |= GCLineWidth; - - gcv.join_style = JoinRound; - gcv.cap_style = CapRound; - - valuemask |= (GCCapStyle | GCJoinStyle); - } - - - /* Set the drawing function. - */ - gcv.function = GXcopy; - valuemask |= GCFunction; - - /* Set the foreground. - */ -/* if (mono_p)*/ - fg = get_pixel_resource (st->dpy, st->cmap, "foreground", "Foreground"); -/* WTF? -else - fg = st->bg ^ get_pixel_resource (st->dpy, st->cmap, ("color0"), "Foreground"); -*/ - gcv.foreground = fg; - valuemask |= GCForeground; - - /* Actually create the GC. - */ - st->color0 = XCreateGC (st->dpy, st->window, valuemask, &gcv); - - return retval; -} - - - - -static void -setup(struct state *st) -{ - XWindowAttributes xgwa; - - XGetWindowAttributes (st->dpy, st->window, &xgwa); - st->cmap = xgwa.colormap; - - st->width = xgwa.width; - st->height = xgwa.height; - st->x_offset = st->width / 2; - st->y_offset = st->height / 2; - st->unit_pixels = st->width < st->height ? st->width : st->height; - - { - if (!st->done) - { - colour_init(st, &xgwa); - st->done = True; - } - } -} - - -static void -color_step(struct state *st, Body *pb, double frac) -{ - if (!mono_p) - { - int newshift = st->ncolors * fmod(frac * st->colour_cycle_rate, 1.0); - if (newshift != st->color_shift_pos) - { - pb->current_color = newshift; - XSetForeground (st->dpy, st->color0, st->colors[pb->current_color].pixel); - st->color_shift_pos = newshift; - } - } -} - - -#if 0 -static long -distance(long x1, long y1, long x2, long y2) -{ - long dx, dy; - - dx = x2 - x1; - dy = y2 - y1; - return dx*dx + dy*dy; -} - -static int poisson_irand(double p) -{ - int r = 1; - while (fabs(frand(1.0)) < p) - ++r; - return r < 1 ? 1 : r; -} -#endif - -static void -precalculate_figure(Body *pb, - double this_xtime, double step, - int *x_max, int *y_max, - int *x_min, int *y_min) -{ - double t; - - move_body(pb, 0.0); /* move once to avoid initial line from origin */ - *x_min = *x_max = pb->x; - *y_min = *y_max = pb->y; - - for (t=0.0; t<this_xtime; t += step) - { - move_body(pb, t); /* move once to avoid initial line from origin */ - if (pb->x > *x_max) - *x_max = pb->x; - if (pb->x < *x_min) - *x_min = pb->x; - if (pb->y > *y_max) - *y_max = pb->y; - if (pb->y < *y_min) - *y_min = pb->y; - } -} - -static int i_max(int a, int b) -{ - return (a>b) ? a : b; -} - -static void rescale_circles(struct state *st, Body *pb, - int x_max, int y_max, - int x_min, int y_min) -{ - double xscale, yscale, scale; - double xm, ym; - - x_max -= st->x_offset; - x_min -= st->x_offset; - y_max -= st->y_offset; - y_min -= st->y_offset; - - x_max = i_max(x_max, -x_min); - y_max = i_max(y_max, -y_min); - - - xm = st->width / 2.0; - ym = st->height / 2.0; - if (x_max > xm) - xscale = xm / x_max; - else - xscale = 1.0; - if (y_max > ym) - yscale = ym / y_max; - else - yscale = 1.0; - - if (xscale < yscale) /* wider than tall */ - scale = xscale; /* ensure width fits onscreen */ - else - scale = yscale; /* ensure height fits onscreen */ - - - scale *= FILL_PROPORTION; /* only fill FILL_PROPORTION of screen */ - if (scale < 1.0) /* only reduce, don't enlarge. */ - { - Circle *p; - for (p=pb->epicycles; p; p=p->pchild) - { - p->radius *= scale; - } - } - else - { - printf("enlarge by x%.2f skipped...\n", scale); - } - - if (st->width > st->height * 5 || /* window has weird aspect */ - st->height > st->width * 5) - { - Circle *p; - double r = (st->width > st->height - ? st->width / (double) st->height - : st->height / (double) st->width); - for (p=pb->epicycles; p; p=p->pchild) - p->radius *= r; - } -} - - -/* angular speeds of the circles are harmonics of a fundamental - * value. That should please the Pythagoreans among you... :-) - */ -static double -random_wdot_max(struct state *st) -{ - /* Maximum and minimum values for the choice of wdot_max. Possible - * epicycle speeds vary from wdot_max to (wdot_max * harmonics). - */ - double minspeed, maxspeed; - minspeed = get_float_resource(st->dpy, "minSpeed", "Double"); - maxspeed = get_float_resource(st->dpy, "maxSpeed", "Double"); - return st->harmonics * (minspeed + FULLCIRCLE * frand(maxspeed-minspeed)); -} - - -static void * -epicycle_init (Display *disp, Window win) -{ - struct state *st = (struct state *) calloc (1, sizeof(*st)); - st->dpy = disp; - st->window = win; - - st->holdtime = get_integer_resource (st->dpy, "holdtime", "Integer"); - - st->circle = FULLCIRCLE; - - XClearWindow(st->dpy, st->window); - st->uncleared = 0; - st->restart = 1; - - st->delay = get_integer_resource (st->dpy, "delay", "Integer"); - st->harmonics = get_integer_resource(st->dpy, "harmonics", "Integer"); - st->divisorPoisson = get_float_resource(st->dpy, "divisorPoisson", "Double"); - - st->timestep = get_float_resource(st->dpy, "timestep", "Double"); - st->timestep_coarse = st->timestep * - get_float_resource(st->dpy, "timestepCoarseFactor", "Double"); - - st->sizeFactorMin = get_float_resource(st->dpy, "sizeFactorMin", "Double"); - st->sizeFactorMax = get_float_resource(st->dpy, "sizeFactorMax", "Double"); - - st->minCircles = get_integer_resource (st->dpy, "minCircles", "Integer"); - st->maxCircles = get_integer_resource (st->dpy, "maxCircles", "Integer"); - - st->xtime = 0; /* is this right? */ - - return st; -} - -static unsigned long -epicycle_draw (Display *dpy, Window window, void *closure) -{ - struct state *st = (struct state *) closure; - int this_delay = st->delay; - - if (st->eraser) { - st->eraser = erase_window (st->dpy, st->window, st->eraser); - return 10000; - } - - if (st->restart) - { - setup(st); - st->restart = 0; - - /* Flush any outstanding events; this has the side effect of - * reducing the number of "false restarts"; resdtarts caused by - * one event (e.g. ConfigureNotify) followed by another - * (e.g. Expose). - */ - - st->wdot_max = random_wdot_max(st); - - if (st->pb0) - { - delete_body(st->pb0); - st->pb0 = NULL; - } - st->pb0 = new_body(st); - st->pb0->x_origin = st->pb0->x = st->x_offset; - st->pb0->y_origin = st->pb0->y = st->y_offset; - - if (st->uncleared) - { - st->eraser = erase_window (st->dpy, st->window, st->eraser); - st->uncleared = 0; - } - - precalculate_figure(st->pb0, st->xtime, st->timestep_coarse, - &st->xmax, &st->ymax, &st->xmin, &st->ymin); - - rescale_circles(st, st->pb0, st->xmax, st->ymax, st->xmin, st->ymin); - - move_body(st->pb0, 0.0); /* move once to avoid initial line from origin */ - move_body(st->pb0, 0.0); /* move once to avoid initial line from origin */ - - - st->T = 0.0; /* start at time zero. */ - - st->L = compute_divisor_lcm(st->pb0->epicycles); - - st->colour_cycle_rate = labs(st->L); - - st->xtime = fabs(st->L * st->circle / st->wdot_max); - - if (st->colors) /* (colors==NULL) if mono_p */ - XSetForeground (st->dpy, st->color0, st->colors[st->pb0->current_color].pixel); - } - - - color_step(st, st->pb0, st->T/st->xtime ); - draw_body(st, st->pb0, st->color0); - st->uncleared = 1; - - - /* Check if the figure is complete...*/ - if (st->T > st->xtime) - { - this_delay = st->holdtime * 1000000; - st->restart = 1; /* begin new figure. */ - } - - - - st->T += st->timestep; - move_body(st->pb0, st->T); - - return this_delay; -} - -static void -epicycle_reshape (Display *dpy, Window window, void *closure, - unsigned int w, unsigned int h) -{ - struct state *st = (struct state *) closure; - st->restart = 1; -} - -static Bool -epicycle_event (Display *dpy, Window window, void *closure, XEvent *e) -{ - struct state *st = (struct state *) closure; - if (screenhack_event_helper (dpy, window, e)) - { - st->restart = 1; - return True; - } - - return False; -} - -static void -epicycle_free (Display *dpy, Window window, void *closure) -{ - struct state *st = (struct state *) closure; - if (st->eraser) eraser_free (st->eraser); - if (st->pb0) delete_body (st->pb0); - XFreeGC (dpy, st->color0); - free (st->colors); - free (st); -} - -XSCREENSAVER_MODULE ("Epicycle", epicycle) |