c/dreammachine/strobe.c

   1 /* strobe.c (<~Harvie 2oo9)
   2  * Dream Machine implementation for GNU/Linux
   3  * usage ./strobe [frequency]
   4  */
   5
   6 //#define __WIN32__
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <unistd.h>
  10 #include <signal.h>
  11 #ifndef __WIN32__
  12   #include <fcntl.h>
  13 #else
  14   #include <windows.h>
  15 #endif
  16
  17 void signal_handler(int signo) {
  18         if(signo == SIGTERM || signo == SIGINT || signo == SIGQUIT) {
  19                 fputs("\033[0m" "\033[2J" "\033[0;0H", stdout); fflush(stdout); //restore default terminal settings
  20                 exit(0);
  21         }
  22 }
  23
  24 int main(int argc, char *argv[]) {
  25         //Settings
  26         char bg_black[]         = "\033[40m\033[1;37m"; //set black background
  27         char bg_white[]         = "\033[47m\033[1;30m"; //set white background
  28         char cls[]                              = "\033[2J" "\033[0;0H"; //clear screen and return to begining of it
  29         char format_str[]       = "%s%s" //"\033[40m\033[1;37m"
  30                 "Warning: this software can cause seizures. Use it on your own risk only! Don't forget to close your eyes! Running at %g Hz (Press ^C to exit)";
  31         double frequency = 10; //Hz
  32
  33         //Compute intervals
  34         int cache_size = 0;
  35         if(argc > 1) {
  36                 frequency = strtod(argv[1], NULL); //get frequency from argv[1] (if present)
  37                 cache_size += sizeof(argv[1]);
  38         }
  39         useconds_t half_interval = (1000000/frequency)/2; //uSeconds
  40
  41         //Pre-cache output strings
  42         cache_size += sizeof(bg_black) + sizeof(cls) + sizeof(format_str) + 5;
  43         char state_a[cache_size];
  44         char state_b[cache_size];
  45
  46         sprintf(state_a, format_str, bg_black, cls, frequency);
  47         sprintf(state_b, format_str, bg_white, cls, frequency);
  48
  49         //Register signals
  50         signal(SIGINT, signal_handler); signal(SIGTERM, signal_handler); signal(SIGQUIT, signal_handler);
  51
  52         //Main loop
  53         while(1) {
  54                 fputs(state_a, stdout);
  55                         fflush(stdout);
  56                         usleep(half_interval);
  57                 #ifndef __WIN32__
  58                 int fflags = fcntl(fileno(stdin), F_GETFL, 0);
  59                 fcntl(fileno(stdin), F_SETFL, fflags | O_NONBLOCK);
  60                                 while(getchar()) puts(".");
  61                 fcntl(fileno(stdin), F_SETFL, fflags);
  62                 #else
  63                 //WARNING! Somehow implement FILE_FLAG_OVERLAPPED & FILE_FLAG_NO_BUFFERING support on windows
  64                         #endif
  65                         if(argc > 2) getchar(); //interactive strobe
  66                 fputs(state_b, stdout);
  67                         fflush(stdout);
  68                         usleep(half_interval);
  69         }
  70 }