--- /dev/null
+/* -*- Mode: C; tab-width: 4 -*-
+ * grav --- simulation of a planetary system.
+ */
+#if !defined( lint ) && !defined( SABER )
+static const char sccsid[] = "@(#)grav.c 4.00 97/01/01 xlockmore";
+#endif
+
+/* Copyright (c) 1993 Greg Bowering <greg@smug.student.adelaide.edu.au>
+ *
+ * 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:
+ * 10-May-97: jwz@jwz.org: turned into a standalone program.
+ * 11-Jul-94: color version
+ * 06-Oct-93: by Greg Bowering <greg@smug.student.adelaide.edu.au>
+ */
+
+#ifdef STANDALONE
+# define PROGCLASS "Grav"
+# define HACK_INIT init_grav
+# define HACK_DRAW draw_grav
+# define grav_opts xlockmore_opts
+# define DEFAULTS "*count: 12 \n" \
+ "*delay: 10000 \n" \
+ "*ncolors: 64 \n"
+# define BRIGHT_COLORS
+# include "xlockmore.h" /* from the xscreensaver distribution */
+#else /* !STANDALONE */
+# include "xlock.h" /* from the xlockmore distribution */
+#endif /* !STANDALONE */
+
+#define GRAV -0.02 /* Gravitational constant */
+#define DIST 16.0
+#define COLLIDE 0.0001
+#define ALMOST 15.99
+#define HALF 0.5
+/* #define INTRINSIC_RADIUS 200.0 */
+#define INTRINSIC_RADIUS ((float) (gp->height/5))
+#define STARRADIUS (unsigned int)(gp->height/(2*DIST))
+#define AVG_RADIUS (INTRINSIC_RADIUS/DIST)
+#define RADIUS (unsigned int)(INTRINSIC_RADIUS/(POS(Z)+DIST))
+
+#define XR HALF*ALMOST
+#define YR HALF*ALMOST
+#define ZR HALF*ALMOST
+
+#define VR 0.04
+
+#define DIMENSIONS 3
+#define X 0
+#define Y 1
+#define Z 2
+
+#define DAMP 0.999999
+#define MaxA 0.1 /* Maximum acceleration (w/ damping) */
+
+#define POS(c) planet->P[c]
+#define VEL(c) planet->V[c]
+#define ACC(c) planet->A[c]
+
+#define Planet(x,y)\
+ if ((x) >= 0 && (y) >= 0 && (x) <= gp->width && (y) <= gp->height) {\
+ if (planet->ri < 2)\
+ XDrawPoint(display, window, gc, (x), (y));\
+ else\
+ XFillArc(display, window, gc,\
+ (x) - planet->ri / 2, (y) - planet->ri / 2, planet->ri, planet->ri,\
+ 0, 23040);\
+ }
+
+#define FLOATRAND(min,max) ((min)+(LRAND()/MAXRAND)*((max)-(min)))
+
+#define DEF_DECAY "False" /* Damping for decaying orbits */
+#define DEF_TRAIL "False" /* For trails (works good in mono only) */
+
+static Bool decay;
+static Bool trail;
+
+static XrmOptionDescRec opts[] =
+{
+ {"-decay", ".grav.decay", XrmoptionNoArg, (caddr_t) "on"},
+ {"+decay", ".grav.decay", XrmoptionNoArg, (caddr_t) "off"},
+ {"-trail", ".grav.trail", XrmoptionNoArg, (caddr_t) "on"},
+ {"+trail", ".grav.trail", XrmoptionNoArg, (caddr_t) "off"}
+};
+static argtype vars[] =
+{
+ {(caddr_t *) & decay, "decay", "Decay", DEF_DECAY, t_Bool},
+ {(caddr_t *) & trail, "trail", "Trail", DEF_TRAIL, t_Bool}
+};
+static OptionStruct desc[] =
+{
+ {"-/+decay", "turn on/off decaying orbits"},
+ {"-/+trail", "turn on/off trail dots"}
+};
+
+ModeSpecOpt grav_opts = { 4, opts, 2, vars, desc };
+
+typedef struct {
+ double P[DIMENSIONS], V[DIMENSIONS], A[DIMENSIONS];
+ int xi, yi, ri;
+ unsigned long colors;
+} planetstruct;
+
+typedef struct {
+ int width, height;
+ int x, y, sr, nplanets;
+ unsigned long starcolor;
+ planetstruct *planets;
+} gravstruct;
+
+static gravstruct *gravs = NULL;
+
+static void
+init_planet(ModeInfo * mi, planetstruct * planet)
+{
+ Display *display = MI_DISPLAY(mi);
+ Window window = MI_WINDOW(mi);
+ GC gc = MI_GC(mi);
+ gravstruct *gp = &gravs[MI_SCREEN(mi)];
+
+ if (MI_NPIXELS(mi) > 2)
+ planet->colors = MI_PIXEL(mi, NRAND(MI_NPIXELS(mi)));
+ else
+ planet->colors = MI_WIN_WHITE_PIXEL(mi);
+ /* Initialize positions */
+ POS(X) = FLOATRAND(-XR, XR);
+ POS(Y) = FLOATRAND(-YR, YR);
+ POS(Z) = FLOATRAND(-ZR, ZR);
+
+ if (POS(Z) > -ALMOST) {
+ planet->xi = (int)
+ ((double) gp->width * (HALF + POS(X) / (POS(Z) + DIST)));
+ planet->yi = (int)
+ ((double) gp->height * (HALF + POS(Y) / (POS(Z) + DIST)));
+ } else
+ planet->xi = planet->yi = -1;
+ planet->ri = RADIUS;
+
+ /* Initialize velocities */
+ VEL(X) = FLOATRAND(-VR, VR);
+ VEL(Y) = FLOATRAND(-VR, VR);
+ VEL(Z) = FLOATRAND(-VR, VR);
+
+ /* Draw planets */
+ Planet(planet->xi, planet->yi);
+}
+
+static void
+draw_planet(ModeInfo * mi, planetstruct * planet)
+{
+ Display *display = MI_DISPLAY(mi);
+ Window window = MI_WINDOW(mi);
+ GC gc = MI_GC(mi);
+ gravstruct *gp = &gravs[MI_SCREEN(mi)];
+ double D; /* A distance variable to work with */
+ register unsigned char cmpt;
+
+ D = POS(X) * POS(X) + POS(Y) * POS(Y) + POS(Z) * POS(Z);
+ if (D < COLLIDE)
+ D = COLLIDE;
+ D = sqrt(D);
+ D = D * D * D;
+ for (cmpt = X; cmpt < DIMENSIONS; cmpt++) {
+ ACC(cmpt) = POS(cmpt) * GRAV / D;
+ if (decay) {
+ if (ACC(cmpt) > MaxA)
+ ACC(cmpt) = MaxA;
+ else if (ACC(cmpt) < -MaxA)
+ ACC(cmpt) = -MaxA;
+ VEL(cmpt) = VEL(cmpt) + ACC(cmpt);
+ VEL(cmpt) *= DAMP;
+ } else {
+ /* update velocity */
+ VEL(cmpt) = VEL(cmpt) + ACC(cmpt);
+ }
+ /* update position */
+ POS(cmpt) = POS(cmpt) + VEL(cmpt);
+ }
+
+ gp->x = planet->xi;
+ gp->y = planet->yi;
+
+ if (POS(Z) > -ALMOST) {
+ planet->xi = (int)
+ ((double) gp->width * (HALF + POS(X) / (POS(Z) + DIST)));
+ planet->yi = (int)
+ ((double) gp->height * (HALF + POS(Y) / (POS(Z) + DIST)));
+ } else
+ planet->xi = planet->yi = -1;
+
+ /* Mask */
+ XSetForeground(display, gc, MI_WIN_BLACK_PIXEL(mi));
+ Planet(gp->x, gp->y);
+ if (trail) {
+ XSetForeground(display, gc, planet->colors);
+ XDrawPoint(display, MI_WINDOW(mi), gc, gp->x, gp->y);
+ }
+ /* Move */
+ gp->x = planet->xi;
+ gp->y = planet->yi;
+ planet->ri = RADIUS;
+
+ /* Redraw */
+ XSetForeground(display, gc, planet->colors);
+ Planet(gp->x, gp->y);
+}
+
+void
+init_grav(ModeInfo * mi)
+{
+ Display *display = MI_DISPLAY(mi);
+ GC gc = MI_GC(mi);
+ gravstruct *gp;
+ unsigned char ball;
+
+ if (gravs == NULL) {
+ if ((gravs = (gravstruct *) calloc(MI_NUM_SCREENS(mi),
+ sizeof (gravstruct))) == NULL)
+ return;
+ }
+ gp = &gravs[MI_SCREEN(mi)];
+
+ gp->width = MI_WIN_WIDTH(mi);
+ gp->height = MI_WIN_HEIGHT(mi);
+
+ gp->sr = STARRADIUS;
+
+ gp->nplanets = MI_BATCHCOUNT(mi);
+ if (gp->nplanets < 0) {
+ if (gp->planets) {
+ (void) free((void *) gp->planets);
+ gp->planets = NULL;
+ }
+ gp->nplanets = NRAND(-gp->nplanets) + 1; /* Add 1 so its not too boring */
+ }
+ if (!gp->planets)
+ gp->planets = (planetstruct *) calloc(gp->nplanets, sizeof (planetstruct));
+
+ XClearWindow(display, MI_WINDOW(mi));
+
+ if (MI_NPIXELS(mi) > 2)
+ gp->starcolor = MI_PIXEL(mi, NRAND(MI_NPIXELS(mi)));
+ else
+ gp->starcolor = MI_WIN_WHITE_PIXEL(mi);
+ for (ball = 0; ball < (unsigned char) gp->nplanets; ball++)
+ init_planet(mi, &gp->planets[ball]);
+
+ /* Draw centrepoint */
+ XDrawArc(display, MI_WINDOW(mi), gc,
+ gp->width / 2 - gp->sr / 2, gp->height / 2 - gp->sr / 2, gp->sr, gp->sr,
+ 0, 23040);
+}
+
+void
+draw_grav(ModeInfo * mi)
+{
+ Display *display = MI_DISPLAY(mi);
+ Window window = MI_WINDOW(mi);
+ GC gc = MI_GC(mi);
+ gravstruct *gp = &gravs[MI_SCREEN(mi)];
+ register unsigned char ball;
+
+ /* Mask centrepoint */
+ XSetForeground(display, gc, MI_WIN_BLACK_PIXEL(mi));
+ XDrawArc(display, window, gc,
+ gp->width / 2 - gp->sr / 2, gp->height / 2 - gp->sr / 2, gp->sr, gp->sr,
+ 0, 23040);
+
+ /* Resize centrepoint */
+ switch (NRAND(4)) {
+ case 0:
+ if (gp->sr < (int) STARRADIUS)
+ gp->sr++;
+ break;
+ case 1:
+ if (gp->sr > 2)
+ gp->sr--;
+ }
+
+ /* Draw centrepoint */
+ XSetForeground(display, gc, gp->starcolor);
+ XDrawArc(display, window, gc,
+ gp->width / 2 - gp->sr / 2, gp->height / 2 - gp->sr / 2, gp->sr, gp->sr,
+ 0, 23040);
+
+ for (ball = 0; ball < (unsigned char) gp->nplanets; ball++)
+ draw_planet(mi, &gp->planets[ball]);
+}
+
+void
+release_grav(ModeInfo * mi)
+{
+ if (gravs != NULL) {
+ int screen;
+
+ for (screen = 0; screen < MI_NUM_SCREENS(mi); screen++) {
+ gravstruct *gp = &gravs[screen];
+
+ if (gp->planets)
+ (void) free((void *) gp->planets);
+ }
+ (void) free((void *) gravs);
+ gravs = NULL;
+ }
+}
+
+void
+refresh_grav(ModeInfo * mi)
+{
+ /* Do nothing, it will refresh by itself */
+}
projects / xscreensaver / blobdiff