minix/lib/libcurses/PSD.doc/twinkle1.c

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/* $NetBSD: twinkle1.c,v 1.6 2005/05/23 04:04:49 christos Exp $ */
/*
*
* Copyright (c) 1980, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)twinkle1.c 8.1 (Berkeley) 6/8/93
*/
#include <curses.h>
#include <signal.h>
/*
* the idea for this program was a product of the imagination of
* Kurt Schoens. Not responsible for minds lost or stolen.
*/
#define NCOLS 80
#define NLINES 24
#define MAXPATTERNS 4
typedef struct {
int y, x;
} LOCS;
static LOCS Layout[NCOLS * NLINES]; /* current board layout */
static int Pattern, /* current pattern number */
Numstars; /* number of stars in pattern */
static void puton(char);
static void makeboard(void);
static int ison(int, int);
static void die(int);
int
main(void)
{
srand(getpid()); /* initialize random sequence */
initscr();
signal(SIGINT, die);
noecho();
nonl();
leaveok(stdscr, TRUE);
scrollok(stdscr, FALSE);
for (;;) {
makeboard(); /* make the board setup */
puton('*'); /* put on '*'s */
puton(' '); /* cover up with ' 's */
}
}
/*
* On program exit, move the cursor to the lower left corner by
* direct addressing, since current location is not guaranteed.
* We lie and say we used to be at the upper right corner to guarantee
* absolute addressing.
*/
static void
die(int n)
{
signal(SIGINT, SIG_IGN);
mvcur(0, COLS - 1, LINES - 1, 0);
endwin();
exit(n);
}
/*
* Make the current board setup. It picks a random pattern and
* calls ison() to determine if the character is on that pattern
* or not.
*/
static void
makeboard(void)
{
int y, x;
LOCS *lp;
Pattern = rand() % MAXPATTERNS;
lp = Layout;
for (y = 0; y < NLINES; y++)
for (x = 0; x < NCOLS; x++)
if (ison(y, x)) {
lp->y = y;
lp->x = x;
lp++;
}
Numstars = lp - Layout;
}
/*
* Return TRUE if (y, x) is on the current pattern.
*/
static int
ison(int y, int x)
{
switch (Pattern) {
case 0: /* alternating lines */
return !(y & 01);
case 1: /* box */
if (x >= LINES && y >= NCOLS)
return FALSE;
if (y < 3 || y >= NLINES - 3)
return TRUE;
return (x < 3 || x >= NCOLS - 3);
case 2: /* holy pattern! */
return ((x + y) & 01);
case 3: /* bar across center */
return (y >= 9 && y <= 15);
}
/* NOTREACHED */
}
static void
puton(char ch)
{
LOCS *lp;
int r;
LOCS *end;
LOCS temp;
end = &Layout[Numstars];
for (lp = Layout; lp < end; lp++) {
r = rand() % Numstars;
temp = *lp;
*lp = Layout[r];
Layout[r] = temp;
}
for (lp = Layout; lp < end; lp++) {
mvaddch(lp->y, lp->x, ch);
refresh();
}
}