xref: /netbsd/lib/libcurses/PSD.doc/twinkle1.c (revision 6550d01e)
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 }
162