#!/usr/bin/env python3.7
# Draws moving dot at ipv6tree.bitnet.be (was jinglepings.com)!
# Needs sudo to run...
#   sudo ./ipv6_image4.py

# Note that normal screen/image conventions are followed...
#   y increasing moves DOWN the TV!
#   (0,0) is the pixel at upper left of the screen






pausee = 0.0002     # minimum time between pings in seconds
ip_base = '2a05:9b81:2021:'




import socket
import time

# screen size
xMax = 1920
yMax = 1080

# initialize
x = 0
y = 0
xIncreasing = True



# xxx and yyy give the pixel
# rgb are between 0 and 255
def send_ping(xxx,yyy,r,g,b):
  addr = ip_base + '%i:%i:%.2x:%.2x:%.2x' % (xxx,yyy,r,g,b)
  #print(addr)
  try:
    send_socket.sendto(b'\x80\0\0\0\0\0\0\0', (addr, 0, 0, 0))
  except:
    pass
  time.sleep(pausee)


send_socket = socket.socket(socket.AF_INET6, socket.SOCK_RAW, socket.getprotobyname('ipv6-icmp'))

r = 0
while True:

  r = (r + 1) % 256
  g = int(y*255/yMax)
  b = int(x*255/xMax)

  send_ping(x,y,r,g,b)

  if xIncreasing:
    x += 1
    if x == xMax-1:
      xIncreasing = False
  else:
    x += -1
    if x == 0:
      xIncreasing = True

  y = (y+1) % yMax


# If you cycle x (not bouncing), then you fall into a pattern because
#   1080*16 = 1920*9
# If you don't cycle x, then you fall into a larger pattern...
#   1080*32 = (1920*2)*9
#
# Actually, since the first pixel doesn't draw, bouncing in either direction prevents patterns because 1079 = 13*83 and 1919 = 19*101 have no common factors with anything.