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/* Copyright (c) 2018, Curtis McEnroe <programble@gmail.com>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <err.h>
#include <fcntl.h>
#include <linux/fb.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sysexits.h>
#include <termios.h>
#include <unistd.h>
extern int init(int argc, char *argv[]);
extern void draw(uint32_t *buf, size_t xres, size_t yres);
extern void input(char in);
static uint32_t *buf;
static struct fb_var_screeninfo info;
static uint32_t saveBg;
static void restoreBg(void) {
for (size_t i = 0; i < info.xres * info.yres; ++i) {
buf[i] = saveBg;
}
}
static struct termios saveTerm;
static void restoreTerm(void) {
tcsetattr(STDERR_FILENO, TCSADRAIN, &saveTerm);
}
int main(int argc, char *argv[]) {
int error;
error = init(argc, argv);
if (error) return error;
const char *path = getenv("FRAMEBUFFER");
if (!path) path = "/dev/fb0";
int fb = open(path, O_RDWR);
if (fb < 0) err(EX_OSFILE, "%s", path);
error = ioctl(fb, FBIOGET_VSCREENINFO, &info);
if (error) err(EX_IOERR, "%s", path);
size_t size = 4 * info.xres * info.yres;
buf = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fb, 0);
if (buf == MAP_FAILED) err(EX_IOERR, "%s", path);
saveBg = buf[0];
atexit(restoreBg);
error = tcgetattr(STDERR_FILENO, &saveTerm);
if (error) err(EX_IOERR, "tcgetattr");
atexit(restoreTerm);
struct termios term = saveTerm;
term.c_lflag &= ~(ICANON | ECHO);
error = tcsetattr(STDERR_FILENO, TCSADRAIN, &term);
if (error) err(EX_IOERR, "tcsetattr");
uint32_t back[info.xres * info.yres];
for (;;) {
draw(back, info.xres, info.yres);
memcpy(buf, back, size);
char in;
ssize_t len = read(STDERR_FILENO, &in, 1);
if (len < 0) err(EX_IOERR, "read");
if (!len) return EX_DATAERR;
input(in);
}
}
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