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
44typedef struct {
45	int	y, x;
46} LOCS;
47
48static LOCS	Layout[NCOLS * NLINES];	/* current board layout */
49
50static int	Pattern,		/* current pattern number */
51		Numstars;		/* number of stars in pattern */
52
53static void puton(char);
54static void die(int);
55static void makeboard(void);
56static int ison(int, int);
57
58static int AM;
59static char *VS;
60static char *TI;
61static char *CL;
62
63int
64main(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 */
121static void
122die(int n)
123{
124	signal(SIGINT, SIG_IGN);
125	mvcur(0, COLS - 1, LINES - 1, 0);
126	endwin();
127	exit(n);
128}
129
130static void
131puton(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 */
168static void
169makeboard(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 */
189static int
190ison(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