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/*-
* Copyright (c) 2015 Dag-Erling Smørgrav
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*
* To CJA, in appreciation of Nighthawk brunches past and future.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/syslog.h>
#include <sys/consio.h>
#include <sys/fbio.h>
#include <dev/fb/fbreg.h>
#include <dev/fb/splashreg.h>
#include <dev/syscons/syscons.h>
#define SAVER_NAME "plasma_saver"
#include "fp16.h"
/*
* Preferred video modes
*/
static int modes[] = {
M_VGA_CG640,
M_PC98_PEGC640x480,
M_PC98_PEGC640x400,
M_VGA_CG320,
-1
};
/*
* Display parameters
*/
static unsigned char *vid;
static unsigned int banksize, scrmode, scrw, scrh;
static unsigned int blanked;
/*
* List of foci
*/
#define FOCI 3
static struct {
int x, y; /* coordinates */
int vx, vy; /* velocity */
} plasma_foci[FOCI];
/*
* Palette
*/
static struct {
unsigned char r, g, b;
} plasma_pal[256];
/*
* Draw a new frame
*/
static void
plasma_update(video_adapter_t *adp)
{
unsigned int x, y; /* coordinates */
signed int dx, dy; /* horizontal / vertical distance */
fp16_t sqd, d; /* square of distance and distance */
fp16_t m; /* magnitude */
unsigned int org, off; /* origin and offset */
unsigned int i; /* loop index */
/* switch to bank 0 */
vidd_set_win_org(adp, 0);
/* for each scan line */
for (y = org = off = 0; y < scrh; ++y) {
/* for each pixel on scan line */
for (x = 0; x < scrw; ++x, ++off) {
/* for each focus */
for (i = m = 0; i < FOCI; ++i) {
dx = x - plasma_foci[i].x;
dy = y - plasma_foci[i].y;
sqd = ItoFP16(dx * dx + dy * dy);
d = fp16_sqrt(sqd);
/* divide by 4 to stretch out the pattern */
m = fp16_sub(m, fp16_cos(d / 4));
}
/*
* m is now in the range +/- FOCI, but we need a
* value between 0 and 255. We scale to +/- 127
* and add 127, which moves it into the range [0,
* 254].
*/
m = fp16_mul(m, ItoFP16(127));
m = fp16_div(m, ItoFP16(FOCI));
m = fp16_add(m, ItoFP16(127));
/* switch banks if necessary */
if (off > banksize) {
off -= banksize;
org += banksize;
vidd_set_win_org(adp, org);
}
/* plot */
vid[off] = FP16toI(m);
}
}
/* now move the foci */
for (i = 0; i < FOCI; ++i) {
plasma_foci[i].x += plasma_foci[i].vx;
if (plasma_foci[i].x < 0) {
/* bounce against left wall */
plasma_foci[i].vx = -plasma_foci[i].vx;
plasma_foci[i].x = -plasma_foci[i].x;
} else if (plasma_foci[i].x >= scrw) {
/* bounce against right wall */
plasma_foci[i].vx = -plasma_foci[i].vx;
plasma_foci[i].x = scrw - (plasma_foci[i].x - scrw);
}
plasma_foci[i].y += plasma_foci[i].vy;
if (plasma_foci[i].y < 0) {
/* bounce against ceiling */
plasma_foci[i].vy = -plasma_foci[i].vy;
plasma_foci[i].y = -plasma_foci[i].y;
} else if (plasma_foci[i].y >= scrh) {
/* bounce against floor */
plasma_foci[i].vy = -plasma_foci[i].vy;
plasma_foci[i].y = scrh - (plasma_foci[i].y - scrh);
}
}
}
/*
* Start or stop the screensaver
*/
static int
plasma_saver(video_adapter_t *adp, int blank)
{
int pl;
if (blank) {
/* switch to graphics mode */
if (blanked <= 0) {
pl = splhigh();
vidd_set_mode(adp, scrmode);
vidd_load_palette(adp, (unsigned char *)plasma_pal);
vidd_set_border(adp, 0);
blanked++;
vid = (unsigned char *)adp->va_window;
banksize = adp->va_window_size;
splx(pl);
vidd_clear(adp);
}
/* update display */
plasma_update(adp);
} else {
blanked = 0;
}
return (0);
}
/*
* Initialize on module load
*/
static int
plasma_init(video_adapter_t *adp)
{
video_info_t info;
int i;
/* select video mode */
for (i = 0; modes[i] >= 0; ++i)
if (vidd_get_info(adp, modes[i], &info) == 0)
break;
if (modes[i] < 0) {
log(LOG_NOTICE, "%s: no supported video modes\n", SAVER_NAME);
return (ENODEV);
}
scrmode = modes[i];
scrw = info.vi_width;
scrh = info.vi_height;
/* initialize the palette */
for (i = 0; i < 256; ++i)
plasma_pal[i].r = plasma_pal[i].g = plasma_pal[i].b = i;
/* randomize the foci */
for (i = 0; i < FOCI; i++) {
plasma_foci[i].x = random() % scrw;
plasma_foci[i].y = random() % scrh;
plasma_foci[i].vx = random() % 5 - 2;
plasma_foci[i].vy = random() % 5 - 2;
}
return (0);
}
/*
* Clean up before module unload
*/
static int
plasma_term(video_adapter_t *adp)
{
return (0);
}
/*
* Boilerplate
*/
static scrn_saver_t plasma_module = {
SAVER_NAME,
plasma_init,
plasma_term,
plasma_saver,
NULL
};
SAVER_MODULE(plasma_saver, plasma_module);
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