Analog Clock v 1.0.3

function HSVtoRGB(hue, sat, val)

  local h = round(hue / 60)
  local f = hue / 60 - h
  local p = val * (1 - sat)
  local q = val * (1 - sat * f)
  local t = val * (1- sat * (1 - f))
  local r, g, b = 0


  if h == 1 then
    r = q
    g = 1
    b = p
  elseif h == 2 then
    r = p
    g = 1
    b = t
  elseif h == 3 then
    r = p
    g = q
    b = 1
  elseif h == 4 then
    r = t
    g = p
    b = 1
  elseif h == 5 then
    r = 1
    g = p
    b = q
  else
    r = 1
    g = t
    b = p
  end

  return r, g, b
end

function round(num, idp)
  local mult = 10^(idp or 0)
  return math.floor(num * mult + 0.5) / mult
end


print("       Analog Clock      ")
sleep(3.0)

gpuCount = 0
gpus = {}
gpuSide = ""

--detecting gpus

sides = {"back","front","left","right","top"}
for i = 1, 5, 1 do
  if peripheral.isPresent(sides[i]) then
    if peripheral.getType(sides[i]) == "gpu" then
      gpuCount = gpuCount + 1                             --increasing gpu count
      table.insert(gpus, (#gpus + 1), sides[i]) --adding gpu to list
    end
  end
end

--tell User
local exit = false

if gpuCount == 0 then
  print("No gpu found!")
  exit = true
elseif (gpuCount > 1) then
  print("More than 1 gpu found!")
  print()
  local reading = true
  while reading do
    print("Please choose:")
    for i = 1, #gpus, 1 do
      print("GPU at side: " .. gpus[i])
    end
    print()
    gpuSide = read()

    for i = 1, #gpus, 1 do

      if gpuSide == gpus[i] then
        reading = false
      end
    end

    if reading == true then
      print("Invaild input!! Please repeat")
      sleep(1.5)
    end
  end

elseif gpuCount == 1 then
  gpuSide = gpus[1]
end

if not exit then
  print("GPU at side " .. gpuSide .. " selected")
  print("")
  print("Do you want the outer ring to crossfade colors? <y/n>")
  local fade = read()

  if fade == "y" or fade == "Y" then
    print("")
    print("")
    repeat
      print("")
      print("How many seconds should it take until the crossfading restart?")
      fadeTime = tonumber(read())
      if  type(fadeTime) ~= "number" or fadeTime <= 0 then print ("Illeagal Input (min = 1)") end
    until type(fadeTime) == "number" and fadeTime > 0
  end

  print("")
  print("")
  print("")
  print("Please enter the frequency of frame updates.")
  print("  smale value (2-10) => more MC FPS, maybe less accurate Time")
  print("")
  print("  high value (>10) => less MC FPS, high accurate Time")
  print("A alue of > 25 is a waste of CPU usage")
  print("")
  print("Recommended: 6.5")

  repeat
    frq = tonumber(read())
    illegalInput = type(frq) ~= "number" or frq < 1 or frq > 35
    if illegalInput then print("Illegal Input (min=1; max=100)") end
  until  not illegalInput
  print("")
  print("")
  print("")
  print("")
  print("")
  print("Hold [Ctrl] + [T] to terminate!")
  sleep(2)
  print("Starting Clock")

  color = 0
  my_r = 0
  my_g = 0.3
  my_b = 1
  lasttick = 0

  --Generate Circle

  clockCode = " glBegin(GL_POINTS)"
  for i = 0,360,1 do
    clockCode = clockCode .. " glVertex2f(".. round(math.cos( math.rad(i) )*63.5 + 63) .. ",".. round(math.sin( math.rad(i) )*63.5 + 64)..")"
  end
  clockCode = clockCode .. " glEnd()"
  --EOF Generate Circle

  while true do
    time = os.time()

    hours = math.floor(time)
    minutes = math.floor((time-hours)*60)

    if fade == "y" or fade == "Y" then
      my_r, my_g, my_b = HSVtoRGB(color, 1, 1)
      color = color + (( os.clock() - lasttick) / fadeTime  * 360)
      lasttick = os.clock()
      if color > 359 then color = 0 end
    end


    clockColor = "glColor3f(" .. my_r .. "," .. my_g .."," .. my_b .. ")"


    -- hourHand

      hourHand = " glColor3f(1,1,1) glBegin(GL_TRIANGLES)"

      hourHand = hourHand .. "  glVertex2f(".. round(math.sin( math.rad((hours % 12) * 30 - 2) )*63.5 + 63) .. ",".. round(math.cos( math.rad((hours % 12) * 30 - 2) )*-63.5 + 64) .. ")"
      hourHand = hourHand .. "  glVertex2f(".. round(math.sin( math.rad((hours % 12) * 30 + 2) )*63.5 + 63) .. ",".. round(math.cos( math.rad((hours % 12) * 30 + 2) )*-63.5 + 64) ..")"
      hourHand = hourHand .. "  glVertex2f(63,64)"


      hourHand = hourHand .. "  glEnd()"

    -- minuteHand

      minuteHand = " glColor3f(0.8,0,0.1) glBegin(GL_TRIANGLES)"

      minuteHand = minuteHand .. "  glVertex2f(".. round(math.sin( math.rad((minutes) * 6 - 1) )*63.5 + 63) .. ",".. round(math.cos( math.rad((minutes) * 6 - 1) )*-63.5 + 64) .. ")"
      minuteHand = minuteHand .. "  glVertex2f(".. round(math.sin( math.rad((minutes) * 6 + 1) )*63.5 + 63) .. ",".. round(math.cos( math.rad((minutes) * 6 + 1) )*-63.5 + 64) ..")"
      minuteHand = minuteHand .. "  glVertex2f(63,64)"

      minuteHand = minuteHand .. "  glEnd()"


    --EOF creating OPENGL code

    gpu.setRenderCode(gpuSide, [[

      gpuBindOutputBuffer(1)
      gpuClearBuffer()
      ]] .. clockColor .. clockCode .. " " .. hourHand .. " " .. minuteHand)

    sleep(1 / frq)
  end

end

print("Going down..")