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 * $FreeBSD$
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_VGA_CG320,
53	-1
54};
55
56/*
57 * Display parameters
58 */
59static unsigned char *vid;
60static unsigned int banksize, scrmode, scrw, scrh;
61static unsigned int blanked;
62
63/*
64 * List of foci
65 */
66#define FOCI 3
67static struct {
68	int x, y;		/* coordinates */
69	int vx, vy;		/* velocity */
70} plasma_foci[FOCI];
71
72/*
73 * Palette
74 */
75static struct {
76	unsigned char r, g, b;
77} plasma_pal[256];
78
79/*
80 * Draw a new frame
81 */
82static void
83plasma_update(video_adapter_t *adp)
84{
85	unsigned int x, y;	/* coordinates */
86	signed int dx, dy;	/* horizontal / vertical distance */
87	fp16_t sqd, d;		/* square of distance and distance */
88	fp16_t m;		/* magnitude */
89	unsigned int org, off;	/* origin and offset */
90	unsigned int i;		/* loop index */
91
92	/* switch to bank 0 */
93	vidd_set_win_org(adp, 0);
94	/* for each scan line */
95	for (y = org = off = 0; y < scrh; ++y) {
96		/* for each pixel on scan line */
97		for (x = 0; x < scrw; ++x, ++off) {
98			/* for each focus */
99			for (i = m = 0; i < FOCI; ++i) {
100				dx = x - plasma_foci[i].x;
101				dy = y - plasma_foci[i].y;
102				sqd = ItoFP16(dx * dx + dy * dy);
103				d = fp16_sqrt(sqd);
104				/* divide by 4 to stretch out the pattern */
105				m = fp16_sub(m, fp16_cos(d / 4));
106			}
107			/*
108			 * m is now in the range +/- FOCI, but we need a
109			 * value between 0 and 255.  We scale to +/- 127
110			 * and add 127, which moves it into the range [0,
111			 * 254].
112			 */
113			m = fp16_mul(m, ItoFP16(127));
114			m = fp16_div(m, ItoFP16(FOCI));
115			m = fp16_add(m, ItoFP16(127));
116			/* switch banks if necessary */
117			if (off > banksize) {
118				off -= banksize;
119				org += banksize;
120				vidd_set_win_org(adp, org);
121			}
122			/* plot */
123			vid[off] = FP16toI(m);
124		}
125	}
126	/* now move the foci */
127	for (i = 0; i < FOCI; ++i) {
128		plasma_foci[i].x += plasma_foci[i].vx;
129		if (plasma_foci[i].x < 0) {
130			/* bounce against left wall */
131			plasma_foci[i].vx = -plasma_foci[i].vx;
132			plasma_foci[i].x = -plasma_foci[i].x;
133		} else if (plasma_foci[i].x >= scrw) {
134			/* bounce against right wall */
135			plasma_foci[i].vx = -plasma_foci[i].vx;
136			plasma_foci[i].x = scrw - (plasma_foci[i].x - scrw);
137		}
138		plasma_foci[i].y += plasma_foci[i].vy;
139		if (plasma_foci[i].y < 0) {
140			/* bounce against ceiling */
141			plasma_foci[i].vy = -plasma_foci[i].vy;
142			plasma_foci[i].y = -plasma_foci[i].y;
143		} else if (plasma_foci[i].y >= scrh) {
144			/* bounce against floor */
145			plasma_foci[i].vy = -plasma_foci[i].vy;
146			plasma_foci[i].y = scrh - (plasma_foci[i].y - scrh);
147		}
148	}
149}
150
151/*
152 * Start or stop the screensaver
153 */
154static int
155plasma_saver(video_adapter_t *adp, int blank)
156{
157	int pl;
158
159	if (blank) {
160		/* switch to graphics mode */
161		if (blanked <= 0) {
162			pl = splhigh();
163			vidd_set_mode(adp, scrmode);
164			vidd_load_palette(adp, (unsigned char *)plasma_pal);
165			vidd_set_border(adp, 0);
166			blanked++;
167			vid = (unsigned char *)adp->va_window;
168			banksize = adp->va_window_size;
169			splx(pl);
170			vidd_clear(adp);
171		}
172		/* update display */
173		plasma_update(adp);
174	} else {
175		blanked = 0;
176	}
177	return (0);
178}
179
180/*
181 * Initialize on module load
182 */
183static int
184plasma_init(video_adapter_t *adp)
185{
186	video_info_t info;
187	int i;
188
189	/* select video mode */
190	for (i = 0; modes[i] >= 0; ++i)
191		if (vidd_get_info(adp, modes[i], &info) == 0)
192			break;
193	if (modes[i] < 0) {
194		log(LOG_NOTICE, "%s: no supported video modes\n", SAVER_NAME);
195		return (ENODEV);
196	}
197	scrmode = modes[i];
198	scrw = info.vi_width;
199	scrh = info.vi_height;
200
201	/* initialize the palette */
202	for (i = 0; i < 256; ++i)
203		plasma_pal[i].r = plasma_pal[i].g = plasma_pal[i].b = i;
204
205	/* randomize the foci */
206	for (i = 0; i < FOCI; i++) {
207		plasma_foci[i].x = random() % scrw;
208		plasma_foci[i].y = random() % scrh;
209		plasma_foci[i].vx = random() % 5 - 2;
210		plasma_foci[i].vy = random() % 5 - 2;
211	}
212
213	return (0);
214}
215
216/*
217 * Clean up before module unload
218 */
219static int
220plasma_term(video_adapter_t *adp)
221{
222
223	return (0);
224}
225
226/*
227 * Boilerplate
228 */
229static scrn_saver_t plasma_module = {
230	SAVER_NAME,
231	plasma_init,
232	plasma_term,
233	plasma_saver,
234	NULL
235};
236
237SAVER_MODULE(plasma_saver, plasma_module);
238