RedMew/map_gen/shape/threaded_spirals.lua

-- Author: flowild

local arm_width = 96

local function is_on_spiral(x, y, distance, angle_offset)
	local angle = angle_offset + math.deg(math.atan2(x, y))

	local offset = distance
	if angle ~= 0 then
		offset = offset + angle / 3.75 * 2
	end
	return offset % 96 * 2 >= 48 * 2
end

return function(x, y, world)
	local pseudo_x = x / (arm_width / 48)
	local pseudo_y = y / (arm_width / 48)
	local distance = math.sqrt(pseudo_x * pseudo_x + pseudo_y * pseudo_y)

	return not (distance > 100 and not is_on_spiral(x, y, distance, 0))
end