local w, h
local tx, ty = 0, 0
local circles = {}

Camera = {} -- We define our camera as a table

function Camera.load() -- Camera.load is now a function we can call
   w, h = love.graphics.getDimensions()
   tx, ty = -w/2, -h/2

   for i=1, 100 do
      table.insert(circles, {
         x = love.math.random(0, w * 2),
         y = love.math.random(0, h * 2),
         r = love.math.random(0, 100)
      })
   end
end

function Camera.mousemoved(x, y, dx, dy) -- As well as Camera.mousemoved
   if love.mouse.isDown(1) then
      tx = math.min(0, math.max(tx + dx, -w))
      ty = math.min(0, math.max(ty + dy, -h))
   end
end

function Camera.draw() -- And now this function will work as well
   love.graphics.translate(tx, ty)

   love.graphics.setColor(0, 255, 0, 100)
   for _, circle in ipairs(circles) do
      love.graphics.circle("fill", circle.x, circle.y, circle.r)
      love.graphics.circle("line", circle.x, circle.y, circle.r)
   end
end