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 * To CJA, in appreciation of Nighthawk brunches past and future.
27 */
28
29#include <sys/param.h>
30#include <sys/systm.h>
31#include <sys/kernel.h>
32#include <sys/module.h>
33#include <sys/syslog.h>
34#include <sys/consio.h>
35#include <sys/fbio.h>
36
37#include <dev/fb/fbreg.h>
38#include <dev/fb/splashreg.h>
39#include <dev/syscons/syscons.h>
40
41#define SAVER_NAME	 "plasma_saver"
42
43#include "fp16.h"
44
45/*
46 * Preferred video modes
47 */
48static int modes[] = {
49	M_VGA_CG640,
50	M_VGA_CG320,
51	-1
52};
53
54/*
55 * Display parameters
56 */
57static unsigned char *vid;
58static unsigned int banksize, scrmode, scrw, scrh;
59static unsigned int blanked;
60
61/*
62 * List of foci
63 */
64#define FOCI 3
65static struct {
66	int x, y;		/* coordinates */
67	int vx, vy;		/* velocity */
68} plasma_foci[FOCI];
69
70/*
71 * Palette
72 */
73static struct {
74	unsigned char r, g, b;
75} plasma_pal[256];
76
77/*
78 * Draw a new frame
79 */
80static void
81plasma_update(video_adapter_t *adp)
82{
83	unsigned int x, y;	/* coordinates */
84	signed int dx, dy;	/* horizontal / vertical distance */
85	fp16_t sqd, d;		/* square of distance and distance */
86	fp16_t m;		/* magnitude */
87	unsigned int org, off;	/* origin and offset */
88	unsigned int i;		/* loop index */
89
90	/* switch to bank 0 */
91	vidd_set_win_org(adp, 0);
92	/* for each scan line */
93	for (y = org = off = 0; y < scrh; ++y) {
94		/* for each pixel on scan line */
95		for (x = 0; x < scrw; ++x, ++off) {
96			/* for each focus */
97			for (i = m = 0; i < FOCI; ++i) {
98				dx = x - plasma_foci[i].x;
99				dy = y - plasma_foci[i].y;
100				sqd = ItoFP16(dx * dx + dy * dy);
101				d = fp16_sqrt(sqd);
102				/* divide by 4 to stretch out the pattern */
103				m = fp16_sub(m, fp16_cos(d / 4));
104			}
105			/*
106			 * m is now in the range +/- FOCI, but we need a
107			 * value between 0 and 255.  We scale to +/- 127
108			 * and add 127, which moves it into the range [0,
109			 * 254].
110			 */
111			m = fp16_mul(m, ItoFP16(127));
112			m = fp16_div(m, ItoFP16(FOCI));
113			m = fp16_add(m, ItoFP16(127));
114			/* switch banks if necessary */
115			if (off > banksize) {
116				off -= banksize;
117				org += banksize;
118				vidd_set_win_org(adp, org);
119			}
120			/* plot */
121			vid[off] = FP16toI(m);
122		}
123	}
124	/* now move the foci */
125	for (i = 0; i < FOCI; ++i) {
126		plasma_foci[i].x += plasma_foci[i].vx;
127		if (plasma_foci[i].x < 0) {
128			/* bounce against left wall */
129			plasma_foci[i].vx = -plasma_foci[i].vx;
130			plasma_foci[i].x = -plasma_foci[i].x;
131		} else if (plasma_foci[i].x >= scrw) {
132			/* bounce against right wall */
133			plasma_foci[i].vx = -plasma_foci[i].vx;
134			plasma_foci[i].x = scrw - (plasma_foci[i].x - scrw);
135		}
136		plasma_foci[i].y += plasma_foci[i].vy;
137		if (plasma_foci[i].y < 0) {
138			/* bounce against ceiling */
139			plasma_foci[i].vy = -plasma_foci[i].vy;
140			plasma_foci[i].y = -plasma_foci[i].y;
141		} else if (plasma_foci[i].y >= scrh) {
142			/* bounce against floor */
143			plasma_foci[i].vy = -plasma_foci[i].vy;
144			plasma_foci[i].y = scrh - (plasma_foci[i].y - scrh);
145		}
146	}
147}
148
149/*
150 * Start or stop the screensaver
151 */
152static int
153plasma_saver(video_adapter_t *adp, int blank)
154{
155	int pl;
156
157	if (blank) {
158		/* switch to graphics mode */
159		if (blanked <= 0) {
160			pl = splhigh();
161			vidd_set_mode(adp, scrmode);
162			vidd_load_palette(adp, (unsigned char *)plasma_pal);
163			vidd_set_border(adp, 0);
164			blanked++;
165			vid = (unsigned char *)adp->va_window;
166			banksize = adp->va_window_size;
167			splx(pl);
168			vidd_clear(adp);
169		}
170		/* update display */
171		plasma_update(adp);
172	} else {
173		blanked = 0;
174	}
175	return (0);
176}
177
178/*
179 * Initialize on module load
180 */
181static int
182plasma_init(video_adapter_t *adp)
183{
184	video_info_t info;
185	int i;
186
187	/* select video mode */
188	for (i = 0; modes[i] >= 0; ++i)
189		if (vidd_get_info(adp, modes[i], &info) == 0)
190			break;
191	if (modes[i] < 0) {
192		log(LOG_NOTICE, "%s: no supported video modes\n", SAVER_NAME);
193		return (ENODEV);
194	}
195	scrmode = modes[i];
196	scrw = info.vi_width;
197	scrh = info.vi_height;
198
199	/* initialize the palette */
200	for (i = 0; i < 256; ++i)
201		plasma_pal[i].r = plasma_pal[i].g = plasma_pal[i].b = i;
202
203	/* randomize the foci */
204	for (i = 0; i < FOCI; i++) {
205		plasma_foci[i].x = random() % scrw;
206		plasma_foci[i].y = random() % scrh;
207		plasma_foci[i].vx = random() % 5 - 2;
208		plasma_foci[i].vy = random() % 5 - 2;
209	}
210
211	return (0);
212}
213
214/*
215 * Clean up before module unload
216 */
217static int
218plasma_term(video_adapter_t *adp)
219{
220
221	return (0);
222}
223
224/*
225 * Boilerplate
226 */
227static scrn_saver_t plasma_module = {
228	SAVER_NAME,
229	plasma_init,
230	plasma_term,
231	plasma_saver,
232	NULL
233};
234
235SAVER_MODULE(plasma_saver, plasma_module);
236