352 lines
8.8 KiB
C
352 lines
8.8 KiB
C
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/* -*- Mode: C; tab-width: 4 -*- */
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/* grav --- planets spinning around a pulsar */
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#if !defined( lint ) && !defined( SABER )
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static const char sccsid[] = "@(#)grav.c 5.00 2000/11/01 xlockmore";
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#endif
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/*-
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* Copyright (c) 1993 by Greg Boewring <gb@pobox.com>
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*
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* Permission to use, copy, modify, and distribute this software and its
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* documentation for any purpose and without fee is hereby granted,
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* provided that the above copyright notice appear in all copies and that
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* both that copyright notice and this permission notice appear in
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* supporting documentation.
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*
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* This file is provided AS IS with no warranties of any kind. The author
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* shall have no liability with respect to the infringement of copyrights,
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* trade secrets or any patents by this file or any part thereof. In no
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* event will the author be liable for any lost revenue or profits or
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* other special, indirect and consequential damages.
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*
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* Revision History:
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* 01-Nov-2000: Allocation checks
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* 10-May-1997: Compatible with xscreensaver
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* 11-Jul-1994: color version
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* 06-Oct-1993: Written by Greg Bowering <gb@pobox.com>
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*/
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#ifdef STANDALONE
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#define MODE_grav
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#define PROGCLASS "Grav"
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#define HACK_INIT init_grav
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#define HACK_DRAW draw_grav
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#define grav_opts xlockmore_opts
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#define DEFAULTS "*delay: 10000 \n" \
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"*count: -12 \n" \
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"*ncolors: 64 \n"
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#define BRIGHT_COLORS
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#include "xlockmore.h" /* in xscreensaver distribution */
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#else /* STANDALONE */
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#include "xlock.h" /* in xlockmore distribution */
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#endif /* STANDALONE */
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#ifdef MODE_grav
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#define DEF_DECAY "False" /* Damping for decaying orbits */
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#define DEF_TRAIL "False" /* For trails (works good in mono only) */
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static Bool decay;
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static Bool trail;
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static XrmOptionDescRec opts[] =
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{
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{(char *) "-decay", (char *) ".grav.decay", XrmoptionNoArg, (caddr_t) "on"},
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{(char *) "+decay", (char *) ".grav.decay", XrmoptionNoArg, (caddr_t) "off"},
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{(char *) "-trail", (char *) ".grav.trail", XrmoptionNoArg, (caddr_t) "on"},
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{(char *) "+trail", (char *) ".grav.trail", XrmoptionNoArg, (caddr_t) "off"}
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};
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static argtype vars[] =
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{
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{(void *) & decay, (char *) "decay", (char *) "Decay", (char *) DEF_DECAY, t_Bool},
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{(void *) & trail, (char *) "trail", (char *) "Trail", (char *) DEF_TRAIL, t_Bool}
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};
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static OptionStruct desc[] =
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{
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{(char *) "-/+decay", (char *) "turn on/off decaying orbits"},
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{(char *) "-/+trail", (char *) "turn on/off trail dots"}
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};
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ModeSpecOpt grav_opts =
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{sizeof opts / sizeof opts[0], opts, sizeof vars / sizeof vars[0], vars, desc};
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#ifdef USE_MODULES
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ModStruct grav_description =
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{"grav", "init_grav", "draw_grav", "release_grav",
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"refresh_grav", "init_grav", (char *) NULL, &grav_opts,
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10000, -12, 1, 1, 64, 1.0, "",
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"Shows orbiting planets", 0, NULL};
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#endif
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#define GRAV -0.02 /* Gravitational constant */
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#define DIST 16.0
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#define COLLIDE 0.0001
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#define ALMOST 15.99
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#define HALF 0.5
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/* #define INTRINSIC_RADIUS 200.0 */
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#define INTRINSIC_RADIUS ((float) (gp->height/5))
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#define STARRADIUS (unsigned int)(gp->height/(2*DIST))
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#define AVG_RADIUS (INTRINSIC_RADIUS/DIST)
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#define RADIUS (unsigned int)(INTRINSIC_RADIUS/(POS(Z)+DIST))
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#define XR HALF*ALMOST
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#define YR HALF*ALMOST
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#define ZR HALF*ALMOST
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#define VR 0.04
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#define DIMENSIONS 3
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#define X 0
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#define Y 1
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#define Z 2
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#define DAMP 0.999999
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#define MaxA 0.1 /* Maximum acceleration (w/ damping) */
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#define POS(c) planet->P[c]
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#define VEL(c) planet->V[c]
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#define ACC(c) planet->A[c]
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#define Planet(x,y)\
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if ((x) >= 0 && (y) >= 0 && (x) <= gp->width && (y) <= gp->height) {\
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if (planet->ri < 2)\
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XDrawPoint(display, window, gc, (x), (y));\
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else\
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XFillArc(display, window, gc,\
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(x) - planet->ri / 2, (y) - planet->ri / 2, planet->ri, planet->ri,\
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0, 23040);\
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}
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#define FLOATRAND(min,max) ((min)+(LRAND()/MAXRAND)*((max)-(min)))
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typedef struct {
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double P[DIMENSIONS], V[DIMENSIONS], A[DIMENSIONS];
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int xi, yi, ri;
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unsigned long colors;
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} planetstruct;
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typedef struct {
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int width, height;
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int x, y, sr, nplanets;
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unsigned long starcolor;
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planetstruct *planets;
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} gravstruct;
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static gravstruct *gravs = (gravstruct *) NULL;
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static void
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init_planet(ModeInfo * mi, planetstruct * planet)
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{
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Display *display = MI_DISPLAY(mi);
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Window window = MI_WINDOW(mi);
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GC gc = MI_GC(mi);
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gravstruct *gp = &gravs[MI_SCREEN(mi)];
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if (MI_NPIXELS(mi) > 2)
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planet->colors = MI_PIXEL(mi, NRAND(MI_NPIXELS(mi)));
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else
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planet->colors = MI_WHITE_PIXEL(mi);
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/* Initialize positions */
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POS(X) = FLOATRAND(-XR, XR);
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POS(Y) = FLOATRAND(-YR, YR);
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POS(Z) = FLOATRAND(-ZR, ZR);
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if (POS(Z) > -ALMOST) {
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planet->xi = (int)
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((double) gp->width * (HALF + POS(X) / (POS(Z) + DIST)));
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planet->yi = (int)
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((double) gp->height * (HALF + POS(Y) / (POS(Z) + DIST)));
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} else
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planet->xi = planet->yi = -1;
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planet->ri = RADIUS;
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/* Initialize velocities */
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VEL(X) = FLOATRAND(-VR, VR);
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VEL(Y) = FLOATRAND(-VR, VR);
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VEL(Z) = FLOATRAND(-VR, VR);
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/* Draw planets */
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Planet(planet->xi, planet->yi);
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}
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static void
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draw_planet(ModeInfo * mi, planetstruct * planet)
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{
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Display *display = MI_DISPLAY(mi);
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Window window = MI_WINDOW(mi);
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GC gc = MI_GC(mi);
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gravstruct *gp = &gravs[MI_SCREEN(mi)];
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double D; /* A distance variable to work with */
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register unsigned char cmpt;
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D = POS(X) * POS(X) + POS(Y) * POS(Y) + POS(Z) * POS(Z);
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if (D < COLLIDE)
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D = COLLIDE;
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D = sqrt(D);
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D = D * D * D;
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for (cmpt = X; cmpt < DIMENSIONS; cmpt++) {
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ACC(cmpt) = POS(cmpt) * GRAV / D;
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if (decay) {
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if (ACC(cmpt) > MaxA)
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ACC(cmpt) = MaxA;
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else if (ACC(cmpt) < -MaxA)
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ACC(cmpt) = -MaxA;
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VEL(cmpt) = VEL(cmpt) + ACC(cmpt);
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VEL(cmpt) *= DAMP;
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} else {
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/* update velocity */
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VEL(cmpt) = VEL(cmpt) + ACC(cmpt);
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}
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/* update position */
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POS(cmpt) = POS(cmpt) + VEL(cmpt);
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}
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gp->x = planet->xi;
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gp->y = planet->yi;
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if (POS(Z) > -ALMOST) {
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planet->xi = (int)
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((double) gp->width * (HALF + POS(X) / (POS(Z) + DIST)));
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planet->yi = (int)
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((double) gp->height * (HALF + POS(Y) / (POS(Z) + DIST)));
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} else
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planet->xi = planet->yi = -1;
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/* Mask */
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XSetForeground(display, gc, MI_BLACK_PIXEL(mi));
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Planet(gp->x, gp->y);
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if (trail) {
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XSetForeground(display, gc, planet->colors);
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XDrawPoint(display, MI_WINDOW(mi), gc, gp->x, gp->y);
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}
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/* Move */
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gp->x = planet->xi;
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gp->y = planet->yi;
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planet->ri = RADIUS;
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/* Redraw */
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XSetForeground(display, gc, planet->colors);
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Planet(gp->x, gp->y);
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}
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void
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init_grav(ModeInfo * mi)
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{
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Display *display = MI_DISPLAY(mi);
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GC gc = MI_GC(mi);
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unsigned char ball;
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gravstruct *gp;
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if (gravs == NULL) {
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if ((gravs = (gravstruct *) calloc(MI_NUM_SCREENS(mi),
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sizeof (gravstruct))) == NULL)
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return;
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}
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gp = &gravs[MI_SCREEN(mi)];
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gp->width = MI_WIDTH(mi);
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gp->height = MI_HEIGHT(mi);
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gp->sr = STARRADIUS;
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gp->nplanets = MI_COUNT(mi);
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if (gp->nplanets < 0) {
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if (gp->planets) {
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free(gp->planets);
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gp->planets = (planetstruct *) NULL;
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}
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gp->nplanets = NRAND(-gp->nplanets) + 1; /* Add 1 so its not too boring */
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}
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if (gp->planets == NULL) {
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if ((gp->planets = (planetstruct *) calloc(gp->nplanets,
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sizeof (planetstruct))) == NULL)
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return;
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}
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MI_CLEARWINDOW(mi);
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if (MI_NPIXELS(mi) > 2)
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gp->starcolor = MI_PIXEL(mi, NRAND(MI_NPIXELS(mi)));
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else
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gp->starcolor = MI_WHITE_PIXEL(mi);
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for (ball = 0; ball < (unsigned char) gp->nplanets; ball++)
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init_planet(mi, &gp->planets[ball]);
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/* Draw centrepoint */
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XDrawArc(display, MI_WINDOW(mi), gc,
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gp->width / 2 - gp->sr / 2, gp->height / 2 - gp->sr / 2, gp->sr, gp->sr,
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0, 23040);
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}
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void
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draw_grav(ModeInfo * mi)
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{
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Display *display = MI_DISPLAY(mi);
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Window window = MI_WINDOW(mi);
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GC gc = MI_GC(mi);
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register unsigned char ball;
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gravstruct *gp;
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if (gravs == NULL)
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return;
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gp = &gravs[MI_SCREEN(mi)];
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if (gp->planets == NULL)
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return;
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MI_IS_DRAWN(mi) = True;
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/* Mask centrepoint */
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XSetForeground(display, gc, MI_BLACK_PIXEL(mi));
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XDrawArc(display, window, gc,
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gp->width / 2 - gp->sr / 2, gp->height / 2 - gp->sr / 2, gp->sr, gp->sr,
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0, 23040);
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/* Resize centrepoint */
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switch (NRAND(4)) {
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case 0:
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if (gp->sr < (int) STARRADIUS)
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gp->sr++;
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break;
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case 1:
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if (gp->sr > 2)
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gp->sr--;
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}
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/* Draw centrepoint */
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XSetForeground(display, gc, gp->starcolor);
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XDrawArc(display, window, gc,
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gp->width / 2 - gp->sr / 2, gp->height / 2 - gp->sr / 2, gp->sr, gp->sr,
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0, 23040);
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for (ball = 0; ball < (unsigned char) gp->nplanets; ball++)
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draw_planet(mi, &gp->planets[ball]);
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}
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void
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release_grav(ModeInfo * mi)
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{
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if (gravs != NULL) {
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int screen;
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for (screen = 0; screen < MI_NUM_SCREENS(mi); screen++) {
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gravstruct *gp = &gravs[screen];
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if (gp->planets)
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free(gp->planets);
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}
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free(gravs);
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gravs = (gravstruct *) NULL;
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}
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}
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void
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refresh_grav(ModeInfo * mi)
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{
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MI_CLEARWINDOW(mi);
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}
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#endif /* MODE_grav */
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