Sphere plotting

local component = require("component")
local keyboard = require("keyboard")
local shell = require("shell")
local hologram = component.hologram

hologram.clear()
--hologram.set(x, y, 20, 2)

function round(num, idp)
  local mult = 10^(idp or 0)
  return math.floor(num * mult + 0.5 ) / mult
end
function HologramSet(x, y, z)
--  hologram.set(round(x),round(y),round(z),2)
  hologram.set(x,y,z,2)
  print("x= " .. x .. " y= " .. y .. " z= " .. z)
end

local r = 10     -- radius
local lats = 50  -- latitude
local longs = 50 -- longitude
local sx = 24
local sy = 24
local sz = 15

for i = 1, lats do
  lat0 = math.pi * (-0.5 + (i - 1) / lats)
  z0 = math.sin(lat0)
  zr0 = math.cos(lat0)

  lat1 = math.pi * (-0.5 + i / lats)
  z1 = math.sin(lat1)
  zr1 = math.cos(lat1)

  for j = 1, longs do
    lng = 2 * math.pi * (j - 1) / longs
    x = math.cos(lng)
    y = math.sin(lng)

    HologramSet(x * zr0 * r + sx, y * zr0 * r + sy, z0 * r + sz)
    HologramSet(x * zr1 * r + sx, y * zr1 * r + sy, z1 * r + sz)
  end

end