1 /* -*- Mode: C; tab-width: 4 -*- */
2 /* grav --- planets spinning around a pulsar */
5 static const char sccsid[] = "@(#)grav.c 5.00 2000/11/01 xlockmore";
9 * Copyright (c) 1993 by Greg Boewring <gb@pobox.com>
11 * Permission to use, copy, modify, and distribute this software and its
12 * documentation for any purpose and without fee is hereby granted,
13 * provided that the above copyright notice appear in all copies and that
14 * both that copyright notice and this permission notice appear in
15 * supporting documentation.
17 * This file is provided AS IS with no warranties of any kind. The author
18 * shall have no liability with respect to the infringement of copyrights,
19 * trade secrets or any patents by this file or any part thereof. In no
20 * event will the author be liable for any lost revenue or profits or
21 * other special, indirect and consequential damages.
24 * 01-Nov-2000: Allocation checks
25 * 10-May-1997: Compatible with xscreensaver
26 * 11-Jul-1994: color version
27 * 06-Oct-1993: Written by Greg Bowering <gb@pobox.com>
32 #define PROGCLASS "Grav"
33 #define HACK_INIT init_grav
34 #define HACK_DRAW draw_grav
35 #define grav_opts xlockmore_opts
36 #define DEFAULTS "*delay: 10000 \n" \
40 #include "xlockmore.h" /* in xscreensaver distribution */
41 #else /* STANDALONE */
42 #include "xlock.h" /* in xlockmore distribution */
44 #endif /* STANDALONE */
48 #define DEF_DECAY "False" /* Damping for decaying orbits */
49 #define DEF_TRAIL "False" /* For trails (works good in mono only) */
54 static XrmOptionDescRec opts[] =
56 {"-decay", ".grav.decay", XrmoptionNoArg, "on"},
57 {"+decay", ".grav.decay", XrmoptionNoArg, "off"},
58 {"-trail", ".grav.trail", XrmoptionNoArg, "on"},
59 {"+trail", ".grav.trail", XrmoptionNoArg, "off"}
61 static argtype vars[] =
63 {&decay, "decay", "Decay", DEF_DECAY, t_Bool},
64 {&trail, "trail", "Trail", DEF_TRAIL, t_Bool}
66 static OptionStruct desc[] =
68 {"-/+decay", "turn on/off decaying orbits"},
69 {"-/+trail", "turn on/off trail dots"}
72 ModeSpecOpt grav_opts =
73 {sizeof opts / sizeof opts[0], opts, sizeof vars / sizeof vars[0], vars, desc};
76 ModStruct grav_description =
77 {"grav", "init_grav", "draw_grav", "release_grav",
78 "refresh_grav", "init_grav", (char *) NULL, &grav_opts,
79 10000, -12, 1, 1, 64, 1.0, "",
80 "Shows orbiting planets", 0, NULL};
84 #define GRAV -0.02 /* Gravitational constant */
86 #define COLLIDE 0.0001
89 /* #define INTRINSIC_RADIUS 200.0 */
90 #define INTRINSIC_RADIUS ((float) (gp->height/5))
91 #define STARRADIUS (unsigned int)(gp->height/(2*DIST))
92 #define AVG_RADIUS (INTRINSIC_RADIUS/DIST)
93 #define RADIUS (unsigned int)(INTRINSIC_RADIUS/(POS(Z)+DIST))
95 #define XR HALF*ALMOST
96 #define YR HALF*ALMOST
97 #define ZR HALF*ALMOST
106 #define DAMP 0.999999
107 #define MaxA 0.1 /* Maximum acceleration (w/ damping) */
109 #define POS(c) planet->P[c]
110 #define VEL(c) planet->V[c]
111 #define ACC(c) planet->A[c]
114 if ((x) >= 0 && (y) >= 0 && (x) <= gp->width && (y) <= gp->height) {\
116 XDrawPoint(display, window, gc, (x), (y));\
118 XFillArc(display, window, gc,\
119 (x) - planet->ri / 2, (y) - planet->ri / 2, planet->ri, planet->ri,\
123 #define FLOATRAND(min,max) ((min)+(LRAND()/MAXRAND)*((max)-(min)))
126 double P[DIMENSIONS], V[DIMENSIONS], A[DIMENSIONS];
128 unsigned long colors;
133 int x, y, sr, nplanets;
134 unsigned long starcolor;
135 planetstruct *planets;
138 static gravstruct *gravs = (gravstruct *) NULL;
141 init_planet(ModeInfo * mi, planetstruct * planet)
143 Display *display = MI_DISPLAY(mi);
144 Window window = MI_WINDOW(mi);
146 gravstruct *gp = &gravs[MI_SCREEN(mi)];
148 if (MI_NPIXELS(mi) > 2)
149 planet->colors = MI_PIXEL(mi, NRAND(MI_NPIXELS(mi)));
151 planet->colors = MI_WHITE_PIXEL(mi);
152 /* Initialize positions */
153 POS(X) = FLOATRAND(-XR, XR);
154 POS(Y) = FLOATRAND(-YR, YR);
155 POS(Z) = FLOATRAND(-ZR, ZR);
157 if (POS(Z) > -ALMOST) {
159 ((double) gp->width * (HALF + POS(X) / (POS(Z) + DIST)));
161 ((double) gp->height * (HALF + POS(Y) / (POS(Z) + DIST)));
163 planet->xi = planet->yi = -1;
166 /* Initialize velocities */
167 VEL(X) = FLOATRAND(-VR, VR);
168 VEL(Y) = FLOATRAND(-VR, VR);
169 VEL(Z) = FLOATRAND(-VR, VR);
172 Planet(planet->xi, planet->yi);
176 draw_planet(ModeInfo * mi, planetstruct * planet)
178 Display *display = MI_DISPLAY(mi);
179 Window window = MI_WINDOW(mi);
181 gravstruct *gp = &gravs[MI_SCREEN(mi)];
182 double D; /* A distance variable to work with */
183 register unsigned char cmpt;
185 D = POS(X) * POS(X) + POS(Y) * POS(Y) + POS(Z) * POS(Z);
190 for (cmpt = X; cmpt < DIMENSIONS; cmpt++) {
191 ACC(cmpt) = POS(cmpt) * GRAV / D;
193 if (ACC(cmpt) > MaxA)
195 else if (ACC(cmpt) < -MaxA)
197 VEL(cmpt) = VEL(cmpt) + ACC(cmpt);
200 /* update velocity */
201 VEL(cmpt) = VEL(cmpt) + ACC(cmpt);
203 /* update position */
204 POS(cmpt) = POS(cmpt) + VEL(cmpt);
210 if (POS(Z) > -ALMOST) {
212 ((double) gp->width * (HALF + POS(X) / (POS(Z) + DIST)));
214 ((double) gp->height * (HALF + POS(Y) / (POS(Z) + DIST)));
216 planet->xi = planet->yi = -1;
219 XSetForeground(display, gc, MI_BLACK_PIXEL(mi));
220 Planet(gp->x, gp->y);
222 XSetForeground(display, gc, planet->colors);
223 XDrawPoint(display, MI_WINDOW(mi), gc, gp->x, gp->y);
231 XSetForeground(display, gc, planet->colors);
232 Planet(gp->x, gp->y);
236 init_grav(ModeInfo * mi)
238 Display *display = MI_DISPLAY(mi);
244 if ((gravs = (gravstruct *) calloc(MI_NUM_SCREENS(mi),
245 sizeof (gravstruct))) == NULL)
248 gp = &gravs[MI_SCREEN(mi)];
250 gp->width = MI_WIDTH(mi);
251 gp->height = MI_HEIGHT(mi);
255 gp->nplanets = MI_COUNT(mi);
256 if (gp->nplanets < 0) {
258 (void) free((void *) gp->planets);
259 gp->planets = (planetstruct *) NULL;
261 gp->nplanets = NRAND(-gp->nplanets) + 1; /* Add 1 so its not too boring */
263 if (gp->planets == NULL) {
264 if ((gp->planets = (planetstruct *) calloc(gp->nplanets,
265 sizeof (planetstruct))) == NULL)
271 if (MI_NPIXELS(mi) > 2)
272 gp->starcolor = MI_PIXEL(mi, NRAND(MI_NPIXELS(mi)));
274 gp->starcolor = MI_WHITE_PIXEL(mi);
275 for (ball = 0; ball < (unsigned char) gp->nplanets; ball++)
276 init_planet(mi, &gp->planets[ball]);
278 /* Draw centrepoint */
279 XDrawArc(display, MI_WINDOW(mi), gc,
280 gp->width / 2 - gp->sr / 2, gp->height / 2 - gp->sr / 2, gp->sr, gp->sr,
285 draw_grav(ModeInfo * mi)
287 Display *display = MI_DISPLAY(mi);
288 Window window = MI_WINDOW(mi);
290 register unsigned char ball;
295 gp = &gravs[MI_SCREEN(mi)];
296 if (gp->planets == NULL)
299 MI_IS_DRAWN(mi) = True;
300 /* Mask centrepoint */
301 XSetForeground(display, gc, MI_BLACK_PIXEL(mi));
302 XDrawArc(display, window, gc,
303 gp->width / 2 - gp->sr / 2, gp->height / 2 - gp->sr / 2, gp->sr, gp->sr,
306 /* Resize centrepoint */
309 if (gp->sr < (int) STARRADIUS)
317 /* Draw centrepoint */
318 XSetForeground(display, gc, gp->starcolor);
319 XDrawArc(display, window, gc,
320 gp->width / 2 - gp->sr / 2, gp->height / 2 - gp->sr / 2, gp->sr, gp->sr,
323 for (ball = 0; ball < (unsigned char) gp->nplanets; ball++)
324 draw_planet(mi, &gp->planets[ball]);
328 release_grav(ModeInfo * mi)
333 for (screen = 0; screen < MI_NUM_SCREENS(mi); screen++) {
334 gravstruct *gp = &gravs[screen];
337 (void) free((void *) gp->planets);
339 (void) free((void *) gravs);
340 gravs = (gravstruct *) NULL;
345 refresh_grav(ModeInfo * mi)
350 #endif /* MODE_grav */