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/*
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
 * License for the specific language governing rights and limitations
 * under the License.
 *
 * The Original Code is NanoScreenSaver.
 *
 * The Initial Developer of the Original Code is Alex Holden.
 * Portions created by Alex Holden are Copyright (C) 2000
 * Alex Holden <alex@linuxhacker.org>. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms
 * of the GNU General Public license (the  "[GNU] License"), in which case the
 * provisions of [GNU] License are applicable instead of those
 * above.  If you wish to allow use of your version of this file only
 * under the terms of the [GNU] License and not to allow others to use
 * your version of this file under the MPL, indicate your decision by
 * deleting  the provisions above and replace  them with the notice and
 * other provisions required by the [GNU] License.  If you do not delete
 * the provisions above, a recipient may use your version of this file
 * under either the MPL or the [GNU] License.
 */
/*
 * A collection of screen savers for Nano-X by Alex Holden.
 */
 
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <math.h>
#include <sys/time.h>
 
#define MWINCLUDECOLORS
#include "nano-X.h"
#include "nsaver.h"
 
void *my_malloc(size_t size)
{
	void *ret;
 
	if(!(ret = malloc(size))) {
		fprintf(stderr, "Out of memory\n");
		exit(1);
	}
 
	return ret;
}
 
void get_random_point_on_screen(nstate *state, GR_COORD *x, GR_COORD *y,
							GR_COLOR *c)
{
	if(x) {
		*x = (int) RANDRANGE(0, (state->si.cols - 1.0));
	}
	if(y) {
		*y = (int) RANDRANGE(0, (state->si.rows - 1.0));
	}
	if(c) {
		*c = MWPALINDEX((int)RANDRANGE(0, (state->si.ncolors - 1)));
	}
}
 
void saver1_init(nstate *state) {}
 
void saver1_exposure(nstate *state)
{
	GrClearWindow(state->main_window, 0);
}
 
void saver1_animate(nstate *state) {}
 
void saver2_init(nstate *state)
{
	(int)state->priv = SAVER2_MAXPIXELS;
	state->animate_interval = SAVER2_DELAY;
}
 
void saver2_exposure(nstate *state)
{
	GrClearWindow(state->main_window, 0);
}
 
void saver2_animate(nstate *state)
{
	GR_COORD x, y;
	GR_COLOR c;
	int pixels = SAVER2_PIXELS_PER_FRAME;
 
	while(pixels--) {
		if(!((int)state->priv--)) {
			(int)state->priv = SAVER2_MAXPIXELS;
			GrClearWindow(state->main_window, 0);
		}
		get_random_point_on_screen(state, &x, &y, &c);
		GrSetGCForeground(state->main_gc, c);
		GrPoint(state->main_window, state->main_gc, x, y);
	}
}
 
void saver3_init(nstate *state)
{
	s3state *s = my_malloc(sizeof(s3state));
	state->priv = s;
	s->maxsegments = SAVER3_MAXSEGMENTS;
	s->lastx = 0;
	s->lasty = 0;
	state->animate_interval = SAVER3_DELAY;
}
 
void saver3_exposure(nstate *state)
{
	GrClearWindow(state->main_window, 0);
}
 
void saver3_animate(nstate *state)
{
	GR_COORD newx, newy;
	GR_COLOR c;
	s3state *s = state->priv;
	int pixels = SAVER3_SEGMENTS_PER_FRAME;
 
	while(pixels--) {
		if(!(s->maxsegments--)) {
			s->maxsegments = SAVER3_MAXSEGMENTS;
			GrClearWindow(state->main_window, 0);
		}
		get_random_point_on_screen(state, &newx, &newy, &c);
		GrSetGCForeground(state->main_gc, c);
		GrLine(state->main_window, state->main_gc, s->lastx, s->lasty,
							newx, newy);
		s->lastx = newx;
		s->lasty = newy;
	}
}
 
void saver4_init(nstate *state)
{
	int i;
 
	s4state *s = my_malloc(sizeof(s4state));
	state->priv = s;
 
	s->length = 0;
 
	for(i = 0; i < SAVER4_NUMWORMS; i++) {
		s->tip = 0;
		get_random_point_on_screen(state, &s->worms[i].points[0].x,
						&s->worms[i].points[0].y,
						&s->worms[i].colour);
	}
 
	state->animate_interval = SAVER4_DELAY;
}
 
void saver4_exposure(nstate *state)
{
	int i;
	s4state *s = state->priv;
 
	GrClearWindow(state->main_window, 0);
 
	if(!s->length) return;
 
	for(i = 0; i < SAVER4_NUMWORMS; i++) {
		GrSetGCForeground(state->main_gc, s->worms[i].colour);
		GrPoints(state->main_window, state->main_gc, s->length,
							s->worms[i].points);
	}
}
 
void saver4_get_new_worm_position(nstate *state, s4state *s, int worm,
						GR_COORD *newx, GR_COORD *newy)
{
	int i;
	GR_COORD oldx = s->worms[worm].points[s->tip].x;
	GR_COORD oldy = s->worms[worm].points[s->tip].y;
 
	do {
		i = (int)RANDRANGE(0, 3.0);
		switch(i) {
			case 0:
				*newx = oldx + 1;
				if(*newx == state->si.cols) *newx = 0;
				break;
			case 1:
				*newx = oldx - 1;
				if(*newx == -1) *newx = state->si.cols - 1;
				break;
			case 2:
				*newx = oldx;
				break;
		}
 
		i = (int)RANDRANGE(0, 3.0);
		switch(i) {
			case 0:
				*newy = oldy + 1;
				if(*newy == state->si.rows) *newy = 0;
				break;
			case 1:
				*newy = oldy - 1;
				if(*newy == -1) *newy = state->si.rows - 1;
				break;
			case 2:
				*newy = oldy;
				break;
		}
	} while((*newx == oldx) && (*newy == oldy));
}
 
int saver4_worm_collides(nstate *state, s4state *s, int x, int y, int thisworm,
								int thispoint)
{
	int i, n;
 
	for(i = 0; i < SAVER4_NUMWORMS; i++) {
		for(n = 0; n < s->length; n++) {
			if((i == thisworm) && (n == thispoint)) continue;
			if((s->worms[i].points[n].x == x) &&
					(s->worms[i].points[n].y) == y) {
				return 1;
			}
		}
	}
	return 0;
}
 
void saver4_animate(nstate *state)
{
	int i, newx, newy, tail, newtip, tries;
	s4state *s = state->priv;
 
	if(s->length == SAVER4_WORMLENGTH) tail = s->tip + 1;
	else tail = 0;
	if(tail == SAVER4_WORMLENGTH) tail = 0;
	newtip = s->tip + 1;
	if(newtip == SAVER4_WORMLENGTH) newtip = 0;
 
	for(i = 0; i < SAVER4_NUMWORMS; i++) {
		if(!saver4_worm_collides(state, s, s->worms[i].points[tail].x,
					s->worms[i].points[tail].y, i, tail)) {
			GrSetGCForeground(state->main_gc, BLACK);
			GrPoint(state->main_window, state->main_gc,
					s->worms[i].points[tail].x,
					s->worms[i].points[tail].y);
		}
		for(tries = SAVER4_COLLISION_RELUCTANCE; tries; tries--) {
				saver4_get_new_worm_position(state, s, i, &newx,
									&newy);
			if(!saver4_worm_collides(state, s, newx, newy, -1, -1))
				break;
		}
		s->worms[i].points[newtip].x = newx;
		s->worms[i].points[newtip].y = newy;
		if(tries) {
			GrSetGCForeground(state->main_gc, s->worms[i].colour);
			GrPoint(state->main_window, state->main_gc, newx, newy);
		}
	}
 
	s->tip = newtip;
	if(s->length < SAVER4_WORMLENGTH) s->length++;
}
 
void saver5_init(nstate *state)
{
	int i;
 
	s5state *s = my_malloc(sizeof(s5state));
	state->priv = s;
 
	s->numstars = 0;
 
	for(i = 0; i < SAVER5_NUMSTARS; i++) {
		s->stars[i].angle = RANDRANGE(0, (2 * M_PI));
		s->stars[i].pos = 1;
	}
 
	state->animate_interval = SAVER5_DELAY;
}
 
int saver5_drawstar(nstate *state, s5state *s, int star, int delete)
{
	int opp, adj;
	GR_COORD x, y;
 
	if(delete) GrSetGCForeground(state->main_gc, BLACK);
	else GrSetGCForeground(state->main_gc, WHITE);
 
	opp = (int)(sin(s->stars[star].angle) * s->stars[star].pos);
	adj = (int)(cos(s->stars[star].angle) * s->stars[star].pos);
 
	x = (state->si.cols / 2) + adj;
	y = (state->si.rows / 2) + opp;
 
	if((x < 0) || (y < 0) || (x >= state->si.cols) || (y >= state->si.rows))
		return 1;
 
	GrPoint(state->main_window, state->main_gc, x, y);
 
	return 0;
}
 
void saver5_exposure(nstate *state)
{
	int i;
	s5state *s = state->priv;
 
	GrClearWindow(state->main_window, 0);
 
	for(i = 0; i < SAVER5_NUMSTARS; i++) {
		saver5_drawstar(state, s, i, 0);
	}
}
 
void saver5_animate(nstate *state)
{
	int i;
	double position, scale, increment;
	s5state *s = state->priv;
 
	if(s->numstars < SAVER5_NUMSTARS) {
		s->numstars += SAVER5_STARS_INCREMENT;
		if(s->numstars > SAVER5_NUMSTARS)
			s->numstars = SAVER5_NUMSTARS;
	}
 
	for(i = 0; i < s->numstars; i++) {
		saver5_drawstar(state, s, i, 1);
		position = (double)s->stars[i].pos /
				(double)(state->si.cols / 2);
		scale = sin((position * M_PI_2) + M_PI + M_PI_2) + 1.0;
		increment = (scale * SAVER5_STARS_ACCEL_RATE) + 1;
		s->stars[i].pos += (int) increment;
		if(saver5_drawstar(state, s, i, 0)) {
			s->stars[i].pos = 1;
			s->stars[i].angle = RANDRANGE(0, (2 * M_PI));
			saver5_drawstar(state, s, i, 0);
		}
	}
}
 
void saver6_init(nstate *state)
{
	int i, n;
 
	s6state *s = my_malloc(sizeof(s6state));
	state->priv = s;
 
	s->new_bolt_time = 0;
 
	for(i = 0; i < SAVER6_MAXBOLTS; i++) {
		s->bolts[i].duration = 0;
		for(n = 0; n < SAVER6_MAXFORKS; n++) {
			s->bolts[i].forks[n].valid = 0;
		}
	}
 
	state->animate_interval = SAVER6_DELAY;
}
 
void saver6_drawfork(nstate *state, s6state *s, int bolt, int fork, int delete)
{
	int i;
 
	if(delete) GrSetGCForeground(state->main_gc, BLACK);
	for(i = 0; i < SAVER6_THICKNESS; i++) {
		if(!delete) {
			if((i < 2) || (i >= SAVER6_THICKNESS - 2))
				 GrSetGCForeground(state->main_gc, LTBLUE);
			else GrSetGCForeground(state->main_gc, WHITE);
		}
		GrPoly(state->main_window, state->main_gc,
				s->bolts[bolt].forks[fork].valid,
				s->bolts[bolt].forks[fork].vertices[i]);
	}
}
 
void saver6_drawbolt(nstate *state, s6state *s, int bolt, int delete)
{
	int n;
 
	for(n = 0; n < SAVER6_MAXFORKS; n++)
		if(s->bolts[bolt].forks[n].valid)
			saver6_drawfork(state, s, bolt, n, delete);
}
 
void saver6_drawlightning(nstate *state, s6state *s, int delete)
{
	int i;
 
	for(i = 0; i < SAVER6_MAXBOLTS; i++) {
		if(s->bolts[i].duration) {
			if(delete) s->bolts[i].duration--;
			saver6_drawbolt(state, s, i, delete);
		}
	}
}
 
void saver6_exposure(nstate *state)
{
	s6state *s = state->priv;
 
	GrClearWindow(state->main_window, 0);
 
	saver6_drawlightning(state, s, 0);
}
 
void saver6_setvertices(s6state *s, int bolt, int fork, int vert, GR_COORD x,
								GR_COORD y)
{
	int i;
 
	for(i = 0; i < SAVER6_THICKNESS; i++) {
		s->bolts[bolt].forks[fork].vertices[i][vert].x = x + i;
		s->bolts[bolt].forks[fork].vertices[i][vert].y = y;
	}
}
 
void saver6_perturb(nstate *state, GR_COORD *x, GR_COORD *y, int maxperturb)
{
	*x += (int)RANDRANGE(0, (maxperturb - 1.0)) -
				(double)(maxperturb / 2.0);
	if(*x < 0) *x = 0;
	if(*x > (state->si.cols - 1)) *x = state->si.cols - 1;
 
	*y += (int)RANDRANGE(0, (maxperturb - 1.0)) -
				(double)(maxperturb / 2.0);
	if(*y < 0) *y = 0;
	if(*y > (state->si.cols - 1)) *y = state->si.cols - 1;
}
 
void saver6_makefork(nstate *state, s6state *s, int bolt, int fork, GR_COORD x,
								GR_COORD y)
{
	int i, vertices;
	double length, incr, pos, angle, scale;
	GR_COORD ex, ey, nx, ny, xlen, ylen;
 
	saver6_setvertices(s, bolt, fork, 0, x , y);
 
	scale = (double)(state->si.rows - y) / (double)state->si.rows;
 
	vertices = (int)(scale * RANDRANGE(SAVER6_MINFULLVERTICES,
						SAVER6_MAXVERTICES));
 
	if(vertices < SAVER6_MINVERTICES) vertices = SAVER6_MINVERTICES;
 
	s->bolts[bolt].forks[fork].valid = vertices;
 
	ey = state->si.rows - SAVER6_MAXEND_Y +
		(int)RANDRANGE(0, SAVER6_MAXEND_Y - 1.0);
	if((ey - y) <= 0) ey = SAVER6_MINDROP;
	if(ey >= (state->si.rows - 1)) ey = state->si.rows - 1;
 
	if(!fork) {
		ex = x + (int)RANDRANGE(0, ((state->si.cols - 1.0) / 2.0));
	} else {
		ex = x + (int)(RANDRANGE(0, (ey - y)) / 2.0) - ((ey - y) / 2.0);
	}
 
	if(ex >= state->si.cols) ex = state->si.cols - 1;
	if(ex < 0) ex = 0;
 
	xlen = MAX(x, ex) - MIN(x, ex);
	ylen = MAX(y, ey) - MIN(y, ey);
 
	length = sqrt(((double)(xlen * xlen) + (double)(ylen * ylen)));
	incr = length / (vertices - 1);
	angle = atan(((double)xlen / (double)ylen));
 
	for(i = vertices - 1; i ; i--) {
		pos = (incr * (i - 1)) + (RANDRANGE(0, SAVER6_MAXZIGZAG) -
					((double)SAVER6_MAXZIGZAG / 2.0));
		if(pos < 0) pos = 0;
		if(pos > length) pos = length;
		nx = x - (pos * sin(angle));
		ny = y + pos * cos(angle);
		saver6_perturb(state, &nx, &ny, SAVER6_MAXZIGZAG);
		saver6_setvertices(s, bolt, fork, i, nx , ny);
	}
}
 
int saver6_makeforks(nstate *state, s6state *s, int bolt, int fork,
						int *vert, int *nextfork)
{
	int thisvert = 1, thisfork;
	double prob;
 
	if(*vert == (s->bolts[bolt].forks[fork].valid - 1)) return 0;
	if(*nextfork == SAVER6_MAXFORKS) return 0;
 
 	prob = (double)SAVER6_FORK_PROBABILITY * ((double)*vert /
				(double)s->bolts[bolt].forks[fork].valid) *
					(1.0 / ((double)fork + 1.0));
	if(RANDRANGE(0, 1) < prob) {
		thisfork = *nextfork;
		saver6_makefork(state, s, bolt, thisfork,
			s->bolts[bolt].forks[fork].vertices[0][*vert].x,
			s->bolts[bolt].forks[fork].vertices[0][*vert].y);
		*nextfork += 1;
		while(saver6_makeforks(state, s, bolt, thisfork, &thisvert,
								nextfork));
	}
 
	*vert += 1;
 
	return 1;
}
 
void saver6_makebolt(nstate *state, s6state *s, int bolt)
{
	GR_COORD x;
	int vert = 1, nextfork = 1, n;
 
	for(n = 0; n < SAVER6_MAXFORKS; n++)
		s->bolts[bolt].forks[n].valid = 0;
 
	x = (int)RANDRANGE(0, (state->si.cols - 1.0));
 
	saver6_makefork(state, s, bolt, 0, x, 0);
 
	while(saver6_makeforks(state, s, bolt, 0, &vert, &nextfork));
}
 
void saver6_newbolt(nstate *state, s6state *s)
{
	int i;
 
	for(i = 0; i < SAVER6_MAXBOLTS; i++) {
		if(!s->bolts[i].duration) {
			saver6_makebolt(state, s, i);
			s->bolts[i].duration = RANDRANGE(SAVER6_MINDURATION,
							SAVER6_MAXDURATION);
			saver6_drawbolt(state, s, i, 0);
			break;
		}
	}
 
	s->new_bolt_time = RANDRANGE(1, SAVER6_MAXNEWBOLTTIME);
}
 
void saver6_perturb_bolt(nstate *state, s6state *s, int bolt, int fork)
{
	int m, o;
	GR_COORD x, ox, y, oy;
 
	for(m = 1; m < s->bolts[bolt].forks[fork].valid; m++) {
		ox = x = s->bolts[bolt].forks[fork].vertices[0][m].x;
		oy = y = s->bolts[bolt].forks[fork].vertices[0][m].y;
		saver6_perturb(state, &x, &y, SAVER6_MAXZIGZAG);
		saver6_setvertices(s, bolt, fork, m, x, y);
		for(o = fork + 1; o < SAVER6_MAXFORKS; o++) {
			if((s->bolts[bolt].forks[o].vertices[0][0].x == ox) &&
				(s->bolts[bolt].forks[o].vertices[0][0].y
								== oy)) {
				saver6_setvertices(s, bolt, o, 0, x, y);
			}
		}
	}
}
 
void saver6_perturb_lightning(nstate *state, s6state *s)
{
	int i, n;
 
	for(i = 0; i < SAVER6_MAXBOLTS; i++) {
		if(!s->bolts[i].duration) continue;
		for(n = 0; n < SAVER6_MAXFORKS; n++) {
			if(!s->bolts[i].forks[n].valid) continue;
			saver6_perturb_bolt(state, s, i, n);
		}
	}
}
 
void saver6_animate(nstate *state)
{
	s6state *s = state->priv;
 
	saver6_drawlightning(state, s, 1);
	saver6_perturb_lightning(state, s);
	saver6_drawlightning(state, s, 0);
 
	if(!s->new_bolt_time--) saver6_newbolt(state, s);
}
 
/* The algorithm used in saver7 was adapted from "grav" by Greg Bowering */
 
void saver7_drawstar(nstate *state, s7state *s)
{
	GrSetGCForeground(state->main_gc, SAVER7_STARCOLOUR);
	GrFillEllipse(state->main_window, state->main_gc, s->starx, s->stary,
				SAVER7_STARRADIUS, SAVER7_STARRADIUS);
}
 
void saver7_drawplanet(nstate *state, s7state *s, int planet, int erase)
{
	if(erase) GrSetGCForeground(state->main_gc, BLACK);
	else GrSetGCForeground(state->main_gc, s->planets[planet].colour);
 
	if((s->planets[planet].ax < 0) || (s->planets[planet].ay < 0) ||
			(s->planets[planet].ax >= state->si.cols) ||
			(s->planets[planet].ay >= state->si.rows)) {
		return;
	}
 
	GrFillEllipse(state->main_window, state->main_gc, s->planets[planet].ax,
				s->planets[planet].ay,
				SAVER7_PLANETRADIUS, SAVER7_PLANETRADIUS);
}
 
void saver7_calc_planet_position(nstate *state, s7state *s, int planet)
{
	if(s->planets[planet].r > -SAVER7_ALMOSTDIST) {
		s->planets[planet].ax = (int)((double) state->si.cols *
			(0.5 + (s->planets[planet].x / (s->planets[planet].r +
							SAVER7_DIST))));
		s->planets[planet].ay = (int)((double) state->si.rows *
			(0.5 + (s->planets[planet].y / (s->planets[planet].r +
							SAVER7_DIST))));
	} else {
		s->planets[planet].ax = -1;
		s->planets[planet].ay = -1;
	}
}
 
void saver7_init(nstate *state)
{
	int i;
	s7state *s = my_malloc(sizeof(s7state));
	state->priv = s;
 
	s->starx = state->si.cols / 2;
	s->stary = state->si.rows / 2;
 
	for(i = 0; i < SAVER7_PLANETS; i++) {
		s->planets[i].r = RANDRANGE(SAVER7_MIN_STARTDIM,
						SAVER7_MAX_STARTDIM);
		s->planets[i].x = RANDRANGE(SAVER7_MIN_STARTDIM,
						SAVER7_MAX_STARTDIM);
		s->planets[i].y = RANDRANGE(SAVER7_MIN_STARTDIM,
						SAVER7_MAX_STARTDIM);
		s->planets[i].rv = RANDRANGE(SAVER7_MIN_STARTVEL,
						SAVER7_MAX_STARTVEL);
		s->planets[i].xv = RANDRANGE(SAVER7_MIN_STARTVEL,
						SAVER7_MAX_STARTVEL);
		s->planets[i].yv = RANDRANGE(SAVER7_MIN_STARTVEL,
						SAVER7_MAX_STARTVEL);
		s->planets[i].colour = RANDRANGE(0, (state->si.ncolors - 1));
		saver7_calc_planet_position(state, s, i);
		saver7_drawplanet(state, s, i, 0);
	}
 
	saver7_drawstar(state, s);
 
	state->animate_interval = SAVER7_DELAY;
}
 
void saver7_exposure(nstate *state)
{
	int i;
	s7state *s = state->priv;
 
	GrClearWindow(state->main_window, 0);
 
	for(i = 0; i < SAVER7_PLANETS; i++)
		saver7_drawplanet(state, s, i, 0);
 
	saver7_drawstar(state, s);
}
 
void saver7_moveplanet(nstate *state, s7state *s, int planet)
{
	double dist;
	double accel;
 
	dist = (s->planets[planet].x * s->planets[planet].x) +
		(s->planets[planet].y * s->planets[planet].y) +
		(s->planets[planet].r * s->planets[planet].r);
	if(dist < SAVER7_COLLIDE) dist = SAVER7_COLLIDE;
	dist = sqrt(dist);
	dist = dist * dist * dist;
 
#ifdef SAVER7_USE_DAMPING
	accel = s->planets[planet].r * SAVER7_G / dist;
	if(accel > SAVER7_MAX_ACCEL) accel = SAVER7_MAX_ACCEL;
	else if(accel < -SAVER7_MAX_ACCEL) accel = -SAVER7_MAX_ACCEL;
	s->planets[planet].rv = (s->planets[planet].rv + accel) *
						SAVER7_DAMPING_FACTOR;
	s->planets[planet].r += s->planets[planet].rv;
	accel = s->planets[planet].x * SAVER7_G / dist;
	if(accel > SAVER7_MAX_ACCEL) accel = SAVER7_MAX_ACCEL;
	else if(accel < -SAVER7_MAX_ACCEL) accel = -SAVER7_MAX_ACCEL;
	s->planets[planet].xv = (s->planets[planet].xv + accel) *
						SAVER7_DAMPING_FACTOR;
	s->planets[planet].x += s->planets[planet].xv;
	accel = s->planets[planet].y * SAVER7_G / dist;
	if(accel > SAVER7_MAX_ACCEL) accel = SAVER7_MAX_ACCEL;
	else if(accel < -SAVER7_MAX_ACCEL) accel = -SAVER7_MAX_ACCEL;
	s->planets[planet].yv = (s->planets[planet].yv + accel) *
						SAVER7_DAMPING_FACTOR;
	s->planets[planet].y += s->planets[planet].yv;
#else
	accel = s->planets[planet].r * SAVER7_G / dist;
	s->planets[planet].rv += accel;
	s->planets[planet].r += s->planets[planet].rv;
	accel = s->planets[planet].x * SAVER7_G / dist;
	s->planets[planet].xv += accel;
	s->planets[planet].x += s->planets[planet].xv;
	accel = s->planets[planet].y * SAVER7_G / dist;
	s->planets[planet].yv += accel;
	s->planets[planet].y += s->planets[planet].yv;
#endif
}
 
void saver7_animate(nstate *state)
{
	int i;
	s7state *s = state->priv;
 
	for(i = 0; i < SAVER7_PLANETS; i++) {
		saver7_moveplanet(state, s, i);
		saver7_drawplanet(state, s, i, 1);
		saver7_calc_planet_position(state, s, i);
		saver7_drawplanet(state, s, i, 0);
	}
	saver7_drawstar(state, s);
}
 
/* The algorithm used in saver8 is based on that found at: 
   http://www.go2net.com/internet/deep/1997/04/16/body.html */
 
void saver8_init(nstate *state)
{
	int red = 0, green = 0, blue = 0, step, i = 0;
 
	s8state *s = my_malloc(sizeof(s8state));
	state->priv = s;
 
	s->current_line = 0;
 
	step = 512 / SAVER8_NUMCOLOURS;
 
	for(green = 255; green > 0; green -= step, blue += step, i++)
		s->colours[i] = GR_RGB(0, green, blue);
	for(blue = 255; blue > 0; blue -= step, red += step, i++)
		s->colours[i] = GR_RGB(red, 0, blue);
 
	state->animate_interval = SAVER8_DELAY;
}
 
void saver8_drawpattern(nstate *state)
{
	int x, col, lines = SAVER8_LINES_PER_FRAME;
	s8state *s = state->priv;
 
	if(!s->current_line)
		s->factor = RANDRANGE(SAVER8_MINFACTOR, SAVER8_MAXFACTOR);
 
	while(s->current_line < state->si.rows) {
		if(!--lines) return;
		for(x = 0; x < state->si.cols; x++) {
			col = ((((x * x) + (s->current_line * s->current_line))
					/ s->factor) % SAVER8_NUMCOLOURS);
			GrSetGCForeground(state->main_gc, s->colours[col]);
			GrPoint(state->main_window, state->main_gc, x,
							s->current_line);
		}
		s->current_line++;
	}
	s->current_line = 0;
}
 
void saver8_exposure(nstate *state)
{
	s8state *s = state->priv;
 
	GrClearWindow(state->main_window, 0);
	s->current_line = 0;
	saver8_drawpattern(state);
}
 
void saver8_animate(nstate *state)
{
	saver8_drawpattern(state);
}
 
int init(nstate *state)
{
	GR_WM_PROPERTIES props;
	GR_BITMAP cursor = 0;
 
	if(!GrOpen()) {
		fprintf(stderr, "Couldn't connect to Nano-X server\n");
		return 3;
	}
 
	GrGetScreenInfo(&state->si);
 
	state->main_window = GrNewWindow(GR_ROOT_WINDOW_ID, 0, 0,
				state->si.cols, state->si.rows, 0, BLACK, 0);
 
	GrSelectEvents(state->main_window, GR_EVENT_MASK_EXPOSURE |
						GR_EVENT_MASK_BUTTON_UP |
						GR_EVENT_MASK_BUTTON_DOWN |
						GR_EVENT_MASK_MOUSE_MOTION |
						GR_EVENT_MASK_KEY_UP |
						GR_EVENT_MASK_KEY_DOWN |
						GR_EVENT_MASK_FOCUS_OUT |
						GR_EVENT_MASK_CLOSE_REQ);
 
	props.flags = GR_WM_FLAGS_PROPS;
	props.props = GR_WM_PROPS_NOMOVE | GR_WM_PROPS_NODECORATE |
			GR_WM_PROPS_NOAUTOMOVE | GR_WM_PROPS_NOAUTORESIZE;
	GrSetWMProperties(state->main_window, &props);
 
	state->main_gc = GrNewGC();
	GrSetGCForeground(state->main_gc, WHITE);
	GrSetGCBackground(state->main_gc, BLACK);
 
	state->animate_interval = 0;
 
	srand(time(0));
 
	init_functions[state->saver](state);
 
	calculate_timeout(state);
 
	GrSelectEvents(GR_ROOT_WINDOW_ID, GR_EVENT_MASK_SCREENSAVER);
 
	GrSetCursor(state->main_window, 1, 1, 1, 1, 0, 0, &cursor, &cursor);
 
	GrMapWindow(state->main_window);
 
	GrSetFocus(state->main_window);
 
	return 0;
}
 
void calculate_timeout(nstate *state)
{
	struct timeval t;
	long u;
 
	gettimeofday(&t, NULL);
	u = t.tv_usec + (state->animate_interval * 1000);
	state->timeout.tv_sec = t.tv_sec + (u / 1000000);
	state->timeout.tv_usec = u % 1000000;
}
 
unsigned long timeout_delay(nstate *state)
{
	struct timeval t;
	signed long s, m, ret;
 
	gettimeofday(&t, NULL);
 
	if(!state->animate_interval) return 0;
 
	if((t.tv_sec > state->timeout.tv_sec) ||
			((t.tv_sec == state->timeout.tv_sec) &&
			t.tv_usec >= state->timeout.tv_usec)) return 1;
 
	s = state->timeout.tv_sec - t.tv_sec;
	m = ((state->timeout.tv_usec - t.tv_usec) / 1000);
	ret = (unsigned long)((1000 * s) + m);
 
	if(ret <= 0) return 1;
	else return ret;
}
 
void do_animate(nstate *state)
{
	struct timeval t;
 
	if(!state->animate_interval) return;
 
	gettimeofday(&t, NULL);
 
	if((t.tv_sec > state->timeout.tv_sec) ||
			((t.tv_sec == state->timeout.tv_sec) &&
			(t.tv_usec >= state->timeout.tv_usec))) {
		animate_functions[state->saver](state);
		calculate_timeout(state);
	}
}
 
int do_screensaver_event(nstate *state)
{
	GR_EVENT_SCREENSAVER *event = &state->event.screensaver;
 
	if(event->activate != GR_FALSE) {
		fprintf(stderr, "Got a non-deactivate screensaver event\n");
		return 0;
	}
 
	return 1;
}
 
int handle_event(nstate *state)
{
	switch(state->event.type) {
		case GR_EVENT_TYPE_EXPOSURE:
			exposure_functions[state->saver](state);
		case GR_EVENT_TYPE_TIMEOUT:
		case GR_EVENT_TYPE_NONE:
			break;
		case GR_EVENT_TYPE_SCREENSAVER:
			if(do_screensaver_event(state)) return 0;
			break;
		case GR_EVENT_TYPE_CLOSE_REQ:
		case GR_EVENT_MASK_BUTTON_UP:
		case GR_EVENT_MASK_BUTTON_DOWN:
		case GR_EVENT_MASK_MOUSE_MOTION:
		case GR_EVENT_MASK_KEY_UP:
		case GR_EVENT_MASK_KEY_DOWN:
		case GR_EVENT_MASK_FOCUS_OUT:
			return 0;
		default:
			fprintf(stderr, "Got unknown event type %d\n",
							state->event.type);
			break;
	}
	do_animate(state);
	return(1);
}
 
int main(int argc, char *argv[])
{
	int ret;
	nstate *state = my_malloc(sizeof(nstate));
 
	if(argc == 2) {
		state->saver = atoi(argv[1]) - 1;
		if((state->saver) < 0 || (state->saver >= NUM_SAVERS)) {
			fprintf(stderr, "Invalid saver number \"%s\"\n",
								argv[1]);
			return 2;
		}
	} else state->saver = 0;
 
	if((ret = init(state))) return ret;
 
	do {
		GrGetNextEventTimeout(&state->event, timeout_delay(state));
	} while(handle_event(state));
 
	GrClose();
 
	return 0;
}