require "bitmap"

local w = 800
local h = 600
local bmp = bitmap.of(w, h, color.black, "Mandelbrot_set")

local max_iters = 570
local zoom = 150

local function mandelbrot()
    for x = 0, w - 1 do
        for y = 0, h - 1 do
            local zx = 0
            local zy = 0
            local c_x = (x - 400) / zoom
            local c_y = (y - 300) / zoom
            local i = max_iters
            while zx * zx + zy * zy < 4 and i > 0 do
                local tmp = zx * zx - zy * zy + c_x
                zy = 2 * zx * zy + c_y
                zx = tmp
                i -= 1
            end
            local r = math.round(i * 255 / max_iters)
            bmp:set(math.round(x), math.round(y), bitmap.rgbColor(r, r, r))
        end
    end
end

mandelbrot()
bmp:view(false, "", "", true)