Bresenham Circle Library

--[[
  Made by fatboychummy

  Edit, use, abuse, and program with anything you wish, Open Source is Open Source.
]]

local function displayBresenhamCircle(xc_, yc_, x, y, func)
  func(xc_+x, yc_+y);
  func(xc_-x, yc_+y);
  func(xc_+x, yc_-y);
  func(xc_-x, yc_-y);
  func(xc_+y, yc_+x);
  func(xc_-y, yc_+x);
  func(xc_+y, yc_-x);
  func(xc_-y, yc_-x);
end

local function drawBresenhamCircle(radius_, xc, yc, func)
  local x = 0
  local y = radius_
  local decisionParameter = 3 - 2 * radius_
  displayBresenhamCircle(xc, yc, x, y, func)

  while y >= x do
    x = x + 1
    if decisionParameter > 0 then
      y = y - 1
      decisionParameter = decisionParameter + 4 * (x - y) + 10
    else
      decisionParameter = decisionParameter + 4 * x + 6
    end
    displayBresenhamCircle(xc, yc, x, y, func)
  end
end

return drawBresenhamCircle