snake_saver.c revision 7500 
1/*-
2 * Copyright (c) 1995 S�ren Schmidt
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer
10 *    in this position and unchanged.
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. The name of the author may not be used to endorse or promote products
15 *    derived from this software withough specific prior written permission
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 *	$Id: snake_saver.c,v 1.1 1995/02/22 13:48:07 sos Exp $
29 */
30
31#include <sys/param.h>
32#include <sys/systm.h>
33#include <sys/conf.h>
34#include <sys/exec.h>
35#include <sys/sysent.h>
36#include <sys/lkm.h>
37#include <sys/errno.h>
38#include <saver.h>
39
40MOD_MISC("snake_saver")
41
42void (*current_saver)();
43void (*old_saver)();
44
45static void
46snake_saver(int blank)
47{
48	const char	saves[] = {"FreeBSD-2.1"};
49	static u_char	*savs[sizeof(saves)-1];
50	static int	dirx, diry;
51	int		f;
52	scr_stat	*scp = cur_console;
53
54	if (blank) {
55		if (!scrn_blanked) {
56			fillw((FG_LIGHTGREY|BG_BLACK)<<8 | scr_map[0x20],
57			      Crtat, scp->xsize * scp->ysize);
58			set_border(0);
59			dirx = (scp->xpos ? 1 : -1);
60			diry = (scp->ypos ?
61				scp->xsize : -scp->xsize);
62			for (f=0; f< sizeof(saves)-1; f++)
63				savs[f] = (u_char *)Crtat + 2 *
64					  (scp->xpos+scp->ypos*scp->xsize);
65			*(savs[0]) = scr_map[*saves];
66			f = scp->ysize * scp->xsize + 5;
67			outb(crtc_addr, 14);
68			outb(crtc_addr+1, f >> 8);
69			outb(crtc_addr, 15);
70			outb(crtc_addr+1, f & 0xff);
71			scrn_blanked = 1;
72		}
73		if (scrn_blanked++ < 4)
74			return;
75		scrn_blanked = 1;
76		*(savs[sizeof(saves)-2]) = scr_map[0x20];
77		for (f=sizeof(saves)-2; f > 0; f--)
78			savs[f] = savs[f-1];
79		f = (savs[0] - (u_char *)Crtat) / 2;
80		if ((f % scp->xsize) == 0 ||
81		    (f % scp->xsize) == scp->xsize - 1 ||
82		    (random() % 50) == 0)
83			dirx = -dirx;
84		if ((f / scp->xsize) == 0 ||
85		    (f / scp->xsize) == scp->ysize - 1 ||
86		    (random() % 20) == 0)
87			diry = -diry;
88		savs[0] += 2*dirx + 2*diry;
89		for (f=sizeof(saves)-2; f>=0; f--)
90			*(savs[f]) = scr_map[saves[f]];
91	}
92	else {
93		if (scrn_blanked) {
94			set_border(scp->border);
95			scrn_blanked = 0;
96			scp->start = 0;
97			scp->end = scp->xsize * scp->ysize;
98		}
99	}
100}
101
102saver_load(struct lkm_table *lkmtp, int cmd)
103{
104	(*current_saver)(0);
105	old_saver = current_saver;
106	current_saver = snake_saver;
107	uprintf("snake screen saver installed\n");
108	return 0;
109}
110
111saver_unload(struct lkm_table *lkmtp, int cmd)
112{
113	(*current_saver)(0);
114	current_saver = old_saver;
115	uprintf("snake screen saver removed\n");
116	return 0;
117}
118
119saver_init(struct lkm_table *lkmtp, int cmd, int ver)
120{
121	DISPATCH(lkmtp, cmd, ver, saver_load, saver_unload, nosys);
122}
123