lib/libcurses/PSD.doc/twinkle2.c

   1 /*      $NetBSD: twinkle2.c,v 1.5 2003/08/07 16:44:29 agc 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  *      @(#)twinkle2.c  8.1 (Berkeley) 6/8/93
  33  */
  34
  35 #include <stdlib.h>
  36 #include <unistd.h>
  37 #include <curses.h>
  38 #include <signal.h>
  39
  40 #define NCOLS   80
  41 #define NLINES  24
  42 #define MAXPATTERNS     4
  43
  44 typedef struct {
  45         int     y, x;
  46 } LOCS;
  47
  48 static LOCS     Layout[NCOLS * NLINES]; /* current board layout */
  49
  50 static int      Pattern,                /* current pattern number */
  51                 Numstars;               /* number of stars in pattern */
  52
  53 static void puton(char);
  54 static void die(int);
  55 static void makeboard(void);
  56 static int ison(int, int);
  57
  58 static int AM;
  59 static char *VS;
  60 static char *TI;
  61 static char *CL;
  62
  63 int
  64 main(void)
  65 {
  66         char    *sp;
  67         char    buf[1024];
  68         char    *ptr = buf;
  69
  70         srand(getpid());                /* initialize random sequence */
  71
  72         if (isatty(0)) {
  73                 initscr();
  74                 gettmode();
  75                 if ((sp = getenv("TERM")) != NULL)
  76                         setterm(sp);
  77                 signal(SIGINT, die);
  78         }
  79         else {
  80                 printf("Need a terminal on fd=%d\n", 0);
  81                 exit(1);
  82         }
  83
  84         tgetent(buf, sp);
  85
  86         AM = tgetflag("am");
  87         TI = tgetstr("ti", &ptr);
  88         if (TI == NULL) {
  89                 printf("terminal does not have the ti capability\n");
  90                 exit(1);
  91         }
  92         VS = tgetstr("vs", &ptr);
  93         if (VS == NULL) {
  94                 printf("terminal does not have the vs capability\n");
  95                 exit(1);
  96         }
  97         CL = tgetstr("cl", &ptr);
  98         if (CL == NULL) {
  99                 printf("terminal does not have the cl capability\n");
 100                 exit(1);
 101         }
 102         puts(TI);
 103         puts(VS);
 104
 105         noecho();
 106         nonl();
 107         tputs(CL, NLINES, putchar);
 108         for (;;) {
 109                 makeboard();            /* make the board setup */
 110                 puton('*');             /* put on '*'s */
 111                 puton(' ');             /* cover up with ' 's */
 112         }
 113 }
 114
 115 /*
 116  * On program exit, move the cursor to the lower left corner by
 117  * direct addressing, since current location is not guaranteed.
 118  * We lie and say we used to be at the upper right corner to guarantee
 119  * absolute addressing.
 120  */
 121 static void
 122 die(int n)
 123 {
 124         signal(SIGINT, SIG_IGN);
 125         mvcur(0, COLS - 1, LINES - 1, 0);
 126         endwin();
 127         exit(n);
 128 }
 129
 130 static void
 131 puton(char ch)
 132 {
 133         LOCS    *lp;
 134         int             r;
 135         LOCS    *end;
 136         LOCS            temp;
 137         static int      lasty, lastx;
 138
 139         end = &Layout[Numstars];
 140         for (lp = Layout; lp < end; lp++) {
 141                 r = rand() % Numstars;
 142                 temp = *lp;
 143                 *lp = Layout[r];
 144                 Layout[r] = temp;
 145         }
 146
 147         for (lp = Layout; lp < end; lp++)
 148                         /* prevent scrolling */
 149                 if (!AM || (lp->y < NLINES - 1 || lp->x < NCOLS - 1)) {
 150                         mvcur(lasty, lastx, lp->y, lp->x);
 151                         putchar(ch);
 152                         lasty = lp->y;
 153                         if ((lastx = lp->x + 1) >= NCOLS)
 154                                 if (AM) {
 155                                         lastx = 0;
 156                                         lasty++;
 157                                 }
 158                                 else
 159                                         lastx = NCOLS - 1;
 160                 }
 161 }
 162
 163 /*
 164  * Make the current board setup.  It picks a random pattern and
 165  * calls ison() to determine if the character is on that pattern
 166  * or not.
 167  */
 168 static void
 169 makeboard(void)
 170 {
 171         int             y, x;
 172         LOCS    *lp;
 173
 174         Pattern = rand() % MAXPATTERNS;
 175         lp = Layout;
 176         for (y = 0; y < NLINES; y++)
 177                 for (x = 0; x < NCOLS; x++)
 178                         if (ison(y, x)) {
 179                                 lp->y = y;
 180                                 lp->x = x;
 181                                 lp++;
 182                         }
 183         Numstars = lp - Layout;
 184 }
 185
 186 /*
 187  * Return TRUE if (y, x) is on the current pattern.
 188  */
 189 static int
 190 ison(int y, int x)
 191 {
 192         switch (Pattern) {
 193           case 0:       /* alternating lines */
 194                 return !(y & 01);
 195           case 1:       /* box */
 196                 if (x >= LINES && y >= NCOLS)
 197                         return FALSE;
 198                 if (y < 3 || y >= NLINES - 3)
 199                         return TRUE;
 200                 return (x < 3 || x >= NCOLS - 3);
 201           case 2:       /* holy pattern! */
 202                 return ((x + y) & 01);
 203           case 3:       /* bar across center */
 204                 return (y >= 9 && y <= 15);
 205         }
 206         /* NOTREACHED */
 207 }