xref: /netbsd-src/lib/libcurses/PSD.doc/twinkle1.c (revision 23c8222edbfb0f0932d88a8351d3a0cf817dfb9e)
1 .\"	$NetBSD: twinkle1.c,v 1.5 2003/08/07 16:44:29 agc Exp $
2 .\"
3 .\" Copyright (c) 1980, 1993
4 .\"	 The Regents of the University of California.  All rights reserved.
5 .\"
6 .\" Redistribution and use in source and binary forms, with or without
7 .\" modification, are permitted provided that the following conditions
8 .\" are met:
9 .\" 1. Redistributions of source code must retain the above copyright
10 .\"    notice, this list of conditions and the following disclaimer.
11 .\" 2. Redistributions in binary form must reproduce the above copyright
12 .\"    notice, this list of conditions and the following disclaimer in the
13 .\"    documentation and/or other materials provided with the distribution.
14 .\" 3. Neither the name of the University nor the names of its contributors
15 .\"    may be used to endorse or promote products derived from this software
16 .\"    without specific prior written permission.
17 .\"
18 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 .\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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24 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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29 .\"
30 .\"	@(#)twinkle1.c	8.1 (Berkeley) 6/8/93
31 .\"
32 # include	<curses.h>
33 # include	<signal.h>
34 
35 /*
36  * the idea for this program was a product of the imagination of
37  * Kurt Schoens.  Not responsible for minds lost or stolen.
38  */
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 LOCS	Layout[NCOLS * NLINES];	/* current board layout */
49 
50 int	Pattern,		/* current pattern number */
51 	Numstars;		/* number of stars in pattern */
52 
53 char	*getenv();
54 
55 int	die();
56 
57 main()
58 {
59 	srand(getpid());		/* initialize random sequence */
60 
61 	initscr();
62 	signal(SIGINT, die);
63 	noecho();
64 	nonl();
65 	leaveok(stdscr, TRUE);
66 	scrollok(stdscr, FALSE);
67 
68 	for (;;) {
69 		makeboard();		/* make the board setup */
70 		puton('*');		/* put on '*'s */
71 		puton(' ');		/* cover up with ' 's */
72 	}
73 }
74 
75 /*
76  * On program exit, move the cursor to the lower left corner by
77  * direct addressing, since current location is not guaranteed.
78  * We lie and say we used to be at the upper right corner to guarantee
79  * absolute addressing.
80  */
81 die()
82 {
83 	signal(SIGINT, SIG_IGN);
84 	mvcur(0, COLS - 1, LINES - 1, 0);
85 	endwin();
86 	exit(0);
87 }
88 
89 
90 /*
91  * Make the current board setup.  It picks a random pattern and
92  * calls ison() to determine if the character is on that pattern
93  * or not.
94  */
95 makeboard()
96 {
97 	reg int		y, x;
98 	reg LOCS	*lp;
99 
100 	Pattern = rand() % MAXPATTERNS;
101 	lp = Layout;
102 	for (y = 0; y < NLINES; y++)
103 		for (x = 0; x < NCOLS; x++)
104 			if (ison(y, x)) {
105 				lp->y = y;
106 				lp->x = x;
107 				lp++;
108 			}
109 	Numstars = lp - Layout;
110 }
111 
112 /*
113  * Return TRUE if (y, x) is on the current pattern.
114  */
115 ison(y, x)
116 reg int	y, x; {
117 
118 	switch (Pattern) {
119 	  case 0:	/* alternating lines */
120 		return !(y & 01);
121 	  case 1:	/* box */
122 		if (x >= LINES && y >= NCOLS)
123 			return FALSE;
124 		if (y < 3 || y >= NLINES - 3)
125 			return TRUE;
126 		return (x < 3 || x >= NCOLS - 3);
127 	  case 2:	/* holy pattern! */
128 		return ((x + y) & 01);
129 	  case 3:	/* bar across center */
130 		return (y >= 9 && y <= 15);
131 	}
132 	/* NOTREACHED */
133 }
134 
135 puton(ch)
136 reg char	ch;
137 {
138 	reg LOCS	*lp;
139 	reg int		r;
140 	reg LOCS	*end;
141 	LOCS		temp;
142 
143 	end = &Layout[Numstars];
144 	for (lp = Layout; lp < end; lp++) {
145 		r = rand() % Numstars;
146 		temp = *lp;
147 		*lp = Layout[r];
148 		Layout[r] = temp;
149 	}
150 
151 	for (lp = Layout; lp < end; lp++) {
152 		mvaddch(lp->y, lp->x, ch);
153 		refresh();
154 	}
155 }
156