lib/libcurses/PSD.doc/twinkle1.c

   1 /*      $NetBSD: twinkle1.c,v 1.6 2005/05/23 04:04:49 christos Exp $    */
   2
   3 /*
   4  *
   5  *  Copyright (c) 1980, 1993
   6  *       The Regents of the University of California.  All rights reserved.
   7  *
   8  *  Redistribution and use in source and binary forms, with or without
   9  *  modification, are permitted provided that the following conditions
  10  *  are met:
  11  *  1. Redistributions of source code must retain the above copyright
  12  *     notice, this list of conditions and the following disclaimer.
  13  *  2. Redistributions in binary form must reproduce the above copyright
  14  *     notice, this list of conditions and the following disclaimer in the
  15  *     documentation and/or other materials provided with the distribution.
  16  *  3. Neither the name of the University nor the names of its contributors
  17  *     may be used to endorse or promote products derived from this software
  18  *     without specific prior written permission.
  19  *
  20  *  THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  *  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  *  ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  *  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  *  OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  *  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  *  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  *  OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  *  SUCH DAMAGE.
  31  *
  32  *      @(#)twinkle1.c  8.1 (Berkeley) 6/8/93
  33  */
  34 #include        <curses.h>
  35 #include        <signal.h>
  36
  37 /*
  38  * the idea for this program was a product of the imagination of
  39  * Kurt Schoens.  Not responsible for minds lost or stolen.
  40  */
  41
  42 #define NCOLS   80
  43 #define NLINES  24
  44 #define MAXPATTERNS     4
  45
  46 typedef struct {
  47         int     y, x;
  48 } LOCS;
  49
  50 static LOCS     Layout[NCOLS * NLINES]; /* current board layout */
  51
  52 static int      Pattern,                /* current pattern number */
  53                 Numstars;               /* number of stars in pattern */
  54
  55 static void puton(char);
  56 static void makeboard(void);
  57 static int ison(int, int);
  58 static void die(int);
  59
  60 int
  61 main(void)
  62 {
  63         srand(getpid());                /* initialize random sequence */
  64
  65         initscr();
  66         signal(SIGINT, die);
  67         noecho();
  68         nonl();
  69         leaveok(stdscr, TRUE);
  70         scrollok(stdscr, FALSE);
  71
  72         for (;;) {
  73                 makeboard();            /* make the board setup */
  74                 puton('*');             /* put on '*'s */
  75                 puton(' ');             /* cover up with ' 's */
  76         }
  77 }
  78
  79 /*
  80  * On program exit, move the cursor to the lower left corner by
  81  * direct addressing, since current location is not guaranteed.
  82  * We lie and say we used to be at the upper right corner to guarantee
  83  * absolute addressing.
  84  */
  85 static void
  86 die(int n)
  87 {
  88         signal(SIGINT, SIG_IGN);
  89         mvcur(0, COLS - 1, LINES - 1, 0);
  90         endwin();
  91         exit(n);
  92 }
  93
  94
  95 /*
  96  * Make the current board setup.  It picks a random pattern and
  97  * calls ison() to determine if the character is on that pattern
  98  * or not.
  99  */
 100 static void
 101 makeboard(void)
 102 {
 103         int             y, x;
 104         LOCS    *lp;
 105
 106         Pattern = rand() % MAXPATTERNS;
 107         lp = Layout;
 108         for (y = 0; y < NLINES; y++)
 109                 for (x = 0; x < NCOLS; x++)
 110                         if (ison(y, x)) {
 111                                 lp->y = y;
 112                                 lp->x = x;
 113                                 lp++;
 114                         }
 115         Numstars = lp - Layout;
 116 }
 117
 118 /*
 119  * Return TRUE if (y, x) is on the current pattern.
 120  */
 121 static int
 122 ison(int y, int x)
 123 {
 124         switch (Pattern) {
 125           case 0:       /* alternating lines */
 126                 return !(y & 01);
 127           case 1:       /* box */
 128                 if (x >= LINES && y >= NCOLS)
 129                         return FALSE;
 130                 if (y < 3 || y >= NLINES - 3)
 131                         return TRUE;
 132                 return (x < 3 || x >= NCOLS - 3);
 133           case 2:       /* holy pattern! */
 134                 return ((x + y) & 01);
 135           case 3:       /* bar across center */
 136                 return (y >= 9 && y <= 15);
 137         }
 138         /* NOTREACHED */
 139 }
 140
 141 static void
 142 puton(char ch)
 143 {
 144         LOCS    *lp;
 145         int     r;
 146         LOCS    *end;
 147         LOCS    temp;
 148
 149         end = &Layout[Numstars];
 150         for (lp = Layout; lp < end; lp++) {
 151                 r = rand() % Numstars;
 152                 temp = *lp;
 153                 *lp = Layout[r];
 154                 Layout[r] = temp;
 155         }
 156
 157         for (lp = Layout; lp < end; lp++) {
 158                 mvaddch(lp->y, lp->x, ch);
 159                 refresh();
 160         }
 161 }