xref: /minix3/lib/libcurses/PSD.doc/twinkle2.c (revision 51ffecc181005cb45a40108612ee28d1daaeeb86)
1 /*	$NetBSD: twinkle2.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  * 	@(#)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
main(void)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
die(int n)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
puton(char ch)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
makeboard(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
ison(int y,int x)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 }
208