136 lines
4.5 KiB
C
136 lines
4.5 KiB
C
/* --------------------------------------------------------------------
|
||
* artnet_receiver.c – tiny Art‑Net DMX receiver
|
||
* -------------------------------------------------------------------- */
|
||
#define _POSIX_C_SOURCE 200112L
|
||
#include "artnet_receiver.h"
|
||
|
||
#include <stdio.h>
|
||
#include <stdlib.h>
|
||
#include <string.h>
|
||
#include <unistd.h>
|
||
#include <arpa/inet.h>
|
||
#include <sys/socket.h>
|
||
#include <pthread.h>
|
||
#include <errno.h>
|
||
|
||
#define ARTNET_PORT 6454
|
||
#define ARTNET_HEADER_SIZE 18 /* "Art-Net\0" + OpCode + … */
|
||
#define OP_DMX 0x5000 /* low‑byte first (little‑endian) */
|
||
|
||
/* --------------------------------------------------------------- */
|
||
static int artnet_sock = -1;
|
||
static pthread_t receiver_thread;
|
||
static volatile bool run_thread = false;
|
||
|
||
/* -----------------------------------------------------------------
|
||
* Helper: map a DMX byte (0‑255) to a signed or unsigned integer
|
||
* ----------------------------------------------------------------- */
|
||
static inline int map_range_uint8(uint8_t v, int dst_min, int dst_max)
|
||
{
|
||
return dst_min + (int)((v * (dst_max - dst_min)) / 255.0);
|
||
}
|
||
|
||
/* -----------------------------------------------------------------
|
||
* The thread that receives Art‑Net packets
|
||
* ----------------------------------------------------------------- */
|
||
static void *receiver_func(void *arg)
|
||
{
|
||
(void)arg; /* unused */
|
||
|
||
struct sockaddr_in from;
|
||
socklen_t fromlen = sizeof(from);
|
||
uint8_t buf[1500]; /* big enough for a full packet */
|
||
|
||
while (run_thread) {
|
||
ssize_t n = recvfrom(artnet_sock, buf, sizeof(buf), 0,
|
||
(struct sockaddr *)&from, &fromlen);
|
||
if (n < 0) {
|
||
if (errno == EINTR) continue;
|
||
perror("recvfrom");
|
||
continue;
|
||
}
|
||
|
||
/* ------------------ quick sanity checks ------------------- */
|
||
if (n < ARTNET_HEADER_SIZE) continue; /* too short */
|
||
if (memcmp(buf, "Art-Net\0", 8) != 0) continue; /* not Art‑Net */
|
||
|
||
uint16_t opcode = buf[8] | (buf[9] << 8); /* little‑endian */
|
||
if (opcode != OP_DMX) continue; /* not ArtDMX */
|
||
|
||
/* --------------------- DMX payload ----------------------- */
|
||
uint16_t universe = buf[14] | (buf[15] << 8); /* not used */
|
||
uint16_t length = buf[16] << 8 | buf[17]; /* big‑endian */
|
||
if (length + ARTNET_HEADER_SIZE != (size_t)n) continue; /* malformed */
|
||
|
||
uint8_t *dmx = buf + ARTNET_HEADER_SIZE; /* first DMX slot */
|
||
|
||
/* --------------------- update shared variables ------------ */
|
||
/* 0 … 11 → rotation angles (0‑180°) */
|
||
for (int i = 0; i < 12 && i < length; ++i) {
|
||
rotAnglesDeg[i] = map_range_uint8(dmx[i], 0, 180);
|
||
}
|
||
///* channel 12 → line thickness (1‑10) */
|
||
//if (length > 12) {
|
||
// LINE_THICKNESS = map_range_uint8(dmx[12], 1, 10);
|
||
//}
|
||
///* channel 13 → top margin (0‑200 px) */
|
||
//if (length > 13) {
|
||
// MARGIN_TOP = map_range_uint8(dmx[13], 0, 200);
|
||
//}
|
||
///* channel 14 → bottom margin (0‑200 px) */
|
||
//if (length > 14) {
|
||
// MARGIN_BOTTOM = map_range_uint8(dmx[14], 0, 200);
|
||
//}
|
||
|
||
/* (Add more channels here if you need them) */
|
||
}
|
||
return NULL;
|
||
}
|
||
|
||
/* -----------------------------------------------------------------
|
||
* Public API
|
||
* ----------------------------------------------------------------- */
|
||
bool artnet_init(void)
|
||
{
|
||
struct sockaddr_in sa;
|
||
|
||
artnet_sock = socket(AF_INET, SOCK_DGRAM, 0);
|
||
if (artnet_sock < 0) {
|
||
perror("socket");
|
||
return false;
|
||
}
|
||
|
||
memset(&sa, 0, sizeof(sa));
|
||
sa.sin_family = AF_INET;
|
||
sa.sin_addr.s_addr = htonl(INADDR_ANY);
|
||
sa.sin_port = htons(ARTNET_PORT);
|
||
|
||
if (bind(artnet_sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
|
||
perror("bind");
|
||
close(artnet_sock);
|
||
artnet_sock = -1;
|
||
return false;
|
||
}
|
||
|
||
run_thread = true;
|
||
if (pthread_create(&receiver_thread, NULL, receiver_func, NULL) != 0) {
|
||
perror("pthread_create");
|
||
close(artnet_sock);
|
||
artnet_sock = -1;
|
||
run_thread = false;
|
||
return false;
|
||
}
|
||
return true;
|
||
}
|
||
|
||
void artnet_stop(void)
|
||
{
|
||
if (!run_thread) return;
|
||
run_thread = false;
|
||
/* Wake the thread if it is blocked in recvfrom */
|
||
shutdown(artnet_sock, SHUT_RDWR);
|
||
pthread_join(receiver_thread, NULL);
|
||
close(artnet_sock);
|
||
artnet_sock = -1;
|
||
}
|