nope-fire.c

/*
 * ----------------------------------------------------------------------------
 * "THE MATE-WARE LICENSE" (Revision 42): <leandro@tia.mat.br> wrote this
 * file.  As long as you retain this notice you can do whatever you want
 * with this stuff.  If we meet some day, and you think this stuff is worth
 * it, you can buy me a Club-Mate in return.               Leandro Pereira
 * ----------------------------------------------------------------------------
 */

#include <arpa/inet.h>
#include <stdbool.h>
#include <errno.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>

#define WIDTH 160
#define HEIGHT 96

static unsigned char fire[WIDTH * HEIGHT];
static struct {
    unsigned char r, g, b;
} palette[256];

#define INIT_PALETTE(index, R, G, B)   do { \
        palette[index].r = (R); \
        palette[index].g = (G); \
        palette[index].b = (B); \
    } while (0)

static void palette_init()
{
    int i;

    for (i = 0; i < 0x20; i++) {
	unsigned char double_i = i << 1;
	unsigned char quad_i = i << 2;
	unsigned char octo_i = i << 3;

	INIT_PALETTE(i, 0, 0, double_i);
	INIT_PALETTE(i + 32, octo_i, 0, 64 - double_i);
	INIT_PALETTE(i + 64, 255, octo_i, 0);
	INIT_PALETTE(i + 96, 0xff, 0xff, quad_i);
	INIT_PALETTE(i + 128, 0xff, 0xff, 64 + quad_i);
	INIT_PALETTE(i + 160, 0xff, 0xff, 128 + quad_i);
	INIT_PALETTE(i + 192, 0xff, 0xff, 192 + i);
	INIT_PALETTE(i + 224, 0xff, 0xff, 224 + i);
    }
}

static void fire_update()
{
    int i;
    int j = WIDTH * (HEIGHT - 1);
    int k;

    for (i = 0; i < WIDTH - 1; i++)
	fire[j + i] = 0xff * (1 + (rand() & 0xf) > 10);

    for (k = 0; k < HEIGHT - 1; k++) {
	fire[j - WIDTH] = (fire[j] + fire[j + 1] + fire[j - WIDTH]) / 3;

	for (i = 1; i < WIDTH - 1; i++) {
	    short temp =
		(fire[j + i] + fire[j + i + 1] + fire[j + i - 1] +
		 fire[j - WIDTH + i]) >> 2;
	    fire[j - WIDTH + i] = temp - (temp > 1);
	}
	j -= WIDTH;
    }
}

int socket_init(void)
{
    int fd;

    fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
    if (fd < 0)
        return -errno;

    struct sockaddr_in nope = {
        .sin_family = AF_INET,
        .sin_port = htons(6073)
    };

    if (inet_pton(AF_INET, "151.217.8.152", &nope.sin_addr) < 0)
        return -errno;
    if (connect(fd, (struct sockaddr *)&nope, sizeof(nope)) < 0)
        return -errno;

    return fd;
}

int main(int argc, char *argv[])
{
    unsigned char firebuf[WIDTH * HEIGHT];
    unsigned char imgbuf[46081] = {0};
    int imgbuf_idx;
    int fd;

    fd = socket_init();
    if (fd < 0) {
        printf("Error while connecting: %s", strerror(-fd));
        return 1;
    }

    palette_init();

    while (true) {
	int i, j;

	fire_update(firebuf);

	for (imgbuf_idx = sizeof(imgbuf), i = HEIGHT - 1; i >= 0; i--) {
	    for (j = WIDTH - 1; j >= 0; j--) {
	        int pixel = fire[i * WIDTH + j];
	        imgbuf[imgbuf_idx--] = palette[pixel].r;
	        imgbuf[imgbuf_idx--] = palette[pixel].g;
	        imgbuf[imgbuf_idx--] = palette[pixel].b;
	    }
	}

	write(fd, imgbuf, sizeof(imgbuf));
    }
}