simple-udp.cc

/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
Compile in rpi-rgb-led-matrix directory.

make  # compile library
g++ -Wall -O3 -g -Iinclude simple-udp.cc -o simple-udp -Llib -lrgbmatrix -lrt -lm -lpthread

*/
#include "led-matrix.h"

#include <arpa/inet.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>

const int kListenPort = 9999;  // The UDP port we listen on.

using namespace rgb_matrix;

volatile bool interrupt_received = false;
static void InterruptHandler(int signo) {
  interrupt_received = true;
}

static FrameCanvas *FillFramebuffer(RGBMatrix *matrix, FrameCanvas *canvas,
                                    const char *buffer) {
  const int width = matrix->width();
  const int height = matrix->height();

  for (int y = 0; y < height; ++y) {
    for (int x = 0; x < width; ++x) {
      int r = *buffer++;
      int g = *buffer++;
      int b = *buffer++;
      canvas->SetPixel(x, y, r, g, b);
    }
  }
  return matrix->SwapOnVSync(canvas);
}

static int usage(const char *progname) {
  fprintf(stderr, "usage: %s [options]\n", progname);
  fprintf(stderr, "Options:\n");
  rgb_matrix::PrintMatrixFlags(stderr);
  return 1;
}

int main(int argc, char *argv[]) {
  RGBMatrix::Options matrix_options;
  rgb_matrix::RuntimeOptions runtime_opt;
  if (!rgb_matrix::ParseOptionsFromFlags(&argc, &argv,
                                         &matrix_options, &runtime_opt)) {
    return usage(argv[0]);
  }

  int port = kListenPort;

  RGBMatrix *matrix = rgb_matrix::CreateMatrixFromOptions(matrix_options,
                                                          runtime_opt);

  FrameCanvas *swap_buffer = matrix->CreateFrameCanvas();

  const int framebuffer_size = matrix->width() * matrix->height() * 3;

  char *const packet_buffer = new char[framebuffer_size];

  struct sigaction sa;
  sa.sa_handler = InterruptHandler;
  sa.sa_flags = SA_RESETHAND | SA_NODEFER;
  sigaction(SIGTERM, &sa, NULL);
  sigaction(SIGINT,  &sa, NULL);

  int s;
  if ((s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0) {
      perror("creating UDP socket");
      exit(1);
  }

  struct sockaddr_in addr;
  memset(&addr, 0, sizeof(addr));
  addr.sin_family = AF_INET;
  addr.sin_addr.s_addr = htonl(INADDR_ANY);
  addr.sin_port = htons(port);
  if (bind(s, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
      perror("bind");
      exit(1);
  }

  matrix->Clear();

  while (!interrupt_received) {
    const ssize_t buffer_bytes = recvfrom(s, packet_buffer, framebuffer_size,
                                          0, NULL, 0);
    if (interrupt_received)
      break;

    if (buffer_bytes < 1)
      continue;

    swap_buffer = FillFramebuffer(matrix, swap_buffer, packet_buffer);
  }

  delete matrix;

  return 0;
}