Circle Generator Computercraft

--Variables

local tArgs={...}

loading = false

if shell==nil then
  loading=true
end

tx,ty=term.getSize()
tx,ty=math.floor(tx),math.floor(ty)

pi=math.pi

px=tx/2
py=ty/2

points={}

if #tArgs>1 then
  if tonumber(tArgs[1]) and tonumber(tArgs[2]) then
    if tonumber(tArgs[2])/4~=math.floor(tonumber(tArgs[2])/4) then
      print("Usage: circles [radius] [npts]")
      print("npts must be divisible by 4")
      error()
    end
    r=tonumber(tArgs[1])
    d=tonumber(tArgs[2])
  else
    print("Usage: circles [radius] [npts]")
    error()
  end
elseif not loading then
  print("Usage: circles [radius] [npts]")
  error()
end

--End Variables

--Formulas/Functions

local function getPoints(a)
  x = r * math.cos(a)
  y = r * math.sin(a)
  return x,y
end

----Below functions are if you are using me as an API

function setX(xval)
  local sxv = tostring(xval)
  local pos=0
  repeat
    pos=pos+1
  until sxv:sub(pos,pos)=="." or pos==#sxv
  if pos==#sxv then pos=pos+1 end
  local num=tonumber(sxv:sub(1,pos-1))+0.5
  px=num
end

function setY(yval)
  local syv = tostring(yval)
  local pos=0
  repeat
    pos=pos+1
  until syv:sub(pos,pos)=="." or pos==#syv
  if pos==#syv then pos=pos+1 end
  local num=tonumber(syv:sub(1,pos-1))+0.5
  py=num
end

function drawCircle(ra,da,cls)
  if ra and da then else
    return false
  end
  r=ra
  d=da
  ----Above functions are if you are using me as an API

  --End Formulas/Functions

  --[[                   DEPRECATED
  repeat
  repeat
    shell.run("clear")
    write("Radius:")
    r = tonumber(read())
  until r~=nil
  until r>0

  repeat
  repeat
    shell.run("clear")
    write("Points (Must be divisible by 4):")
    d = tonumber(read())
  until d~=nil
  until d>3 and d/4==math.floor(d/4)
  ]]--                                           DEPRECATED

  if not loading and cls then shell.run("clear") elseif cls
    term.clear()
  end

  --Get All Points

  for i=1,4 do
    ip=d/4
    cpi=(pi/2)*(i-1)
    npi=(pi/2)*(i)
    for j=0,ip-1 do
      a=j*(pi/(ip+3))+cpi
      nx,ny = getPoints(a)
      table.insert(points,{nx,ny})
      --print("Angle: "..a)
    end
  end

  --End Point Getting

  term.setBackgroundColor(colors.white)
  for i=1,#points do
    --print(points[i][1])
    --print(points[i][2])
    term.setCursorPos(px-points[i][1],py-points[i][2])
    write(" ")
  end
  term.setBackgroundColor(colors.black)
  return true
end
if #tArgs>1 then drawCircle(r,d) end