plasma_saver.c revision 294783 
1/*-
2 * Copyright (c) 2015 Dag-Erling Sm��rgrav
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 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: stable/10/sys/dev/syscons/plasma/plasma_saver.c 294783 2016-01-26 08:55:31Z des $
27 *
28 * To CJA, in appreciation of Nighthawk brunches past and future.
29 */
30
31#include <sys/param.h>
32#include <sys/systm.h>
33#include <sys/kernel.h>
34#include <sys/module.h>
35#include <sys/syslog.h>
36#include <sys/consio.h>
37#include <sys/fbio.h>
38
39#include <dev/fb/fbreg.h>
40#include <dev/fb/splashreg.h>
41#include <dev/syscons/syscons.h>
42
43#define SAVER_NAME	 "plasma_saver"
44
45#include "fp16.h"
46
47/*
48 * Preferred video modes
49 */
50static int modes[] = {
51	M_VGA_CG640,
52	M_PC98_PEGC640x480,
53	M_PC98_PEGC640x400,
54	M_VGA_CG320,
55	-1
56};
57
58/*
59 * Display parameters
60 */
61static unsigned char *vid;
62static unsigned int banksize, scrmode, scrw, scrh;
63static unsigned int blanked;
64
65/*
66 * List of foci
67 */
68#define FOCI 3
69static struct {
70	int x, y;		/* coordinates */
71	int vx, vy;		/* velocity */
72} plasma_foci[FOCI];
73
74/*
75 * Palette
76 */
77static struct {
78	unsigned char r, g, b;
79} plasma_pal[256];
80
81/*
82 * Draw a new frame
83 */
84static void
85plasma_update(video_adapter_t *adp)
86{
87	unsigned int x, y;	/* coordinates */
88	signed int dx, dy;	/* horizontal / vertical distance */
89	fp16_t sqd, d;		/* square of distance and distance */
90	fp16_t m;		/* magnitude */
91	unsigned int org, off;	/* origin and offset */
92	unsigned int i;		/* loop index */
93
94	/* switch to bank 0 */
95	vidd_set_win_org(adp, 0);
96	/* for each scan line */
97	for (y = org = off = 0; y < scrh; ++y) {
98		/* for each pixel on scan line */
99		for (x = 0; x < scrw; ++x, ++off) {
100			/* for each focus */
101			for (i = m = 0; i < FOCI; ++i) {
102				dx = x - plasma_foci[i].x;
103				dy = y - plasma_foci[i].y;
104				sqd = ItoFP16(dx * dx + dy * dy);
105				d = fp16_sqrt(sqd);
106				/* divide by 4 to stretch out the pattern */
107				m = fp16_sub(m, fp16_cos(d / 4));
108			}
109			/*
110			 * m is now in the range +/- FOCI, but we need a
111			 * value between 0 and 255.  We scale to +/- 127
112			 * and add 127, which moves it into the range [0,
113			 * 254].
114			 */
115			m = fp16_mul(m, ItoFP16(127));
116			m = fp16_div(m, ItoFP16(FOCI));
117			m = fp16_add(m, ItoFP16(127));
118			/* switch banks if necessary */
119			if (off > banksize) {
120				off -= banksize;
121				org += banksize;
122				vidd_set_win_org(adp, org);
123			}
124			/* plot */
125			vid[off] = FP16toI(m);
126		}
127	}
128	/* now move the foci */
129	for (i = 0; i < FOCI; ++i) {
130		plasma_foci[i].x += plasma_foci[i].vx;
131		if (plasma_foci[i].x < 0) {
132			/* bounce against left wall */
133			plasma_foci[i].vx = -plasma_foci[i].vx;
134			plasma_foci[i].x = -plasma_foci[i].x;
135		} else if (plasma_foci[i].x >= scrw) {
136			/* bounce against right wall */
137			plasma_foci[i].vx = -plasma_foci[i].vx;
138			plasma_foci[i].x = scrw - (plasma_foci[i].x - scrw);
139		}
140		plasma_foci[i].y += plasma_foci[i].vy;
141		if (plasma_foci[i].y < 0) {
142			/* bounce against ceiling */
143			plasma_foci[i].vy = -plasma_foci[i].vy;
144			plasma_foci[i].y = -plasma_foci[i].y;
145		} else if (plasma_foci[i].y >= scrh) {
146			/* bounce against floor */
147			plasma_foci[i].vy = -plasma_foci[i].vy;
148			plasma_foci[i].y = scrh - (plasma_foci[i].y - scrh);
149		}
150	}
151}
152
153/*
154 * Start or stop the screensaver
155 */
156static int
157plasma_saver(video_adapter_t *adp, int blank)
158{
159	int pl;
160
161	if (blank) {
162		/* switch to graphics mode */
163		if (blanked <= 0) {
164			pl = splhigh();
165			vidd_set_mode(adp, scrmode);
166			vidd_load_palette(adp, (unsigned char *)plasma_pal);
167			vidd_set_border(adp, 0);
168			blanked++;
169			vid = (unsigned char *)adp->va_window;
170			banksize = adp->va_window_size;
171			splx(pl);
172			vidd_clear(adp);
173		}
174		/* update display */
175		plasma_update(adp);
176	} else {
177		blanked = 0;
178	}
179	return (0);
180}
181
182/*
183 * Initialize on module load
184 */
185static int
186plasma_init(video_adapter_t *adp)
187{
188	video_info_t info;
189	int i;
190
191	/* select video mode */
192	for (i = 0; modes[i] >= 0; ++i)
193		if (vidd_get_info(adp, modes[i], &info) == 0)
194			break;
195	if (modes[i] < 0) {
196		log(LOG_NOTICE, "%s: no supported video modes\n", SAVER_NAME);
197		return (ENODEV);
198	}
199	scrmode = modes[i];
200	scrw = info.vi_width;
201	scrh = info.vi_height;
202
203	/* initialize the palette */
204	for (i = 0; i < 256; ++i)
205		plasma_pal[i].r = plasma_pal[i].g = plasma_pal[i].b = i;
206
207	/* randomize the foci */
208	for (i = 0; i < FOCI; i++) {
209		plasma_foci[i].x = random() % scrw;
210		plasma_foci[i].y = random() % scrh;
211		plasma_foci[i].vx = random() % 5 - 2;
212		plasma_foci[i].vy = random() % 5 - 2;
213	}
214
215	return (0);
216}
217
218/*
219 * Clean up before module unload
220 */
221static int
222plasma_term(video_adapter_t *adp)
223{
224
225	return (0);
226}
227
228/*
229 * Boilerplate
230 */
231static scrn_saver_t plasma_module = {
232	SAVER_NAME,
233	plasma_init,
234	plasma_term,
235	plasma_saver,
236	NULL
237};
238
239SAVER_MODULE(plasma_saver, plasma_module);
240