Matrix clone in C

cmatrix.c

/*
 * "Bleh" -- a "potato-friendly" cmatrix clone.
 *
 * Screenshot: https://i.imgur.com/dt6RmU7.png
 *
 * Adapted to Windows from:
 *   https://www.reddit.com/r/commandline/comments/1jcnyht/bleh_a_potatofriendly_cmatrix_clone/
 */
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <time.h>
#include <conio.h>
#include <windows.h>

#define DELAY_MS       80
#define RAND_RANGE     94
#define MIN_STREAM_LEN 5

typedef struct {
        uint16_t x;
        uint16_t y;
        uint16_t prev_y;
        uint8_t  length;
        uint8_t  active;
      } Stream;

static int get_terminal_size (uint16_t *rows, uint16_t *cols)
{
  CONSOLE_SCREEN_BUFFER_INFO console_info;
  HANDLE console_hnd = GetStdHandle (STD_OUTPUT_HANDLE);
  int    okay = (console_hnd != INVALID_HANDLE_VALUE &&
                 GetConsoleScreenBufferInfo(console_hnd, &console_info) &&
                 GetFileType(console_hnd) == FILE_TYPE_CHAR);
  if (okay)
  {
    *rows = console_info.srWindow.Bottom - console_info.srWindow.Top + 1;
    *cols = console_info.srWindow.Right - console_info.srWindow.Left + 1;
  }
  return (okay);
}

int main (void)
{
  uint16_t i, j, max_y, max_x;

  if (!get_terminal_size(&max_y, &max_x))
  {
    fprintf (stderr, "Failed to get the screen-size.\n");
    return (1);
  }

  srand ((unsigned int) time(NULL));

  Stream *streams = calloc (max_x, sizeof(Stream));
  if (!streams)
     return (1);

  for (i = 0; i < max_x; i++)
  {
    streams [i].x      = i;
    streams [i].y      = rand() % max_y;
    streams [i].prev_y = streams[i].y;
    streams [i].length = (rand() % (max_y / 2)) + MIN_STREAM_LEN;
    streams [i].active = rand() & 1;
  }

  printf ("\e[2J\e[?25l");

  while (!_kbhit())
  {
    for (i = 0; i < max_x; i++)
    {
      if (streams[i].active)
      {
        uint16_t y      = streams [i].y;
        uint16_t prev_y = streams [i].prev_y;
        uint8_t  len    = streams [i].length;

        if (y != prev_y)
        {
          for (j = 0; j < len; j++)
          {
            uint16_t prev_pos = prev_y - j;

            if (prev_pos >= 0 && prev_pos < max_y)
               printf ("\e[%d;%dH ", prev_pos + 1, i + 1);
          }
        }

        if (y < max_y + len)
        {
          for (j = 0; j < len; j++)
          {
            uint16_t pos = y - j;

            if (pos >= 0 && pos < max_y)
               printf ("\e[%d;%dH%s%c",
                       pos + 1, i + 1, j == 0 ? "\e[97m" : "\e[32m",
                       (rand() % RAND_RANGE) + 33);
          }
        }
        streams[i].prev_y = y;

        if (++streams[i].y - len >= max_y)
        {
          streams [i].y      = 0;
          streams [i].prev_y = 0;
          streams [i].length = (rand() % (max_y / 2)) + MIN_STREAM_LEN;
          streams [i].active = (rand() % 5) != 0;
        }
      }
      else if ((rand() % 50) == 0)
      {
        streams [i].active = 1;
        streams [i].y      = 0;
        streams [i].prev_y = 0;
        streams [i].length = (rand() % (max_y / 2)) + MIN_STREAM_LEN;
      }
    }
    fflush (stdout);
    Sleep (DELAY_MS);
  }

  printf ("\e[?25h\e[0m");
  fflush (stdout);
  free (streams);
  return (0);
}