LÖVE

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local starimage = love.graphics.newImage("images/star.png")

Background = class()

function Background:init(numstars) -- 120 stars normally
	self.numstars = numstars
	self.parallax = {}
	self.colors = {
		[1] = {255, 192, 192}, -- red
		[2] = {255, 255, 255}, -- normal
		[3] = {255, 255, 192}, -- yellow
		[4] = {192, 192, 255}, -- blue
	}
	
	-- create stars
	for i = 1, numstars do
		local x, y = math.random(0, xres*1.2), math.random(0, yres*1.2)
		local depth = math.random(50, 90)/100
		local color = math.random(#self.colors)
		local size = math.random(3,6)/10
		table.insert(self.parallax, {x, y, depth=depth, color=color, size=size})
	end
	
end

function Background:draw()
	-- local variables = faster!
	local starimage = starimage
	local campos = camera.pos
	local xres, yres = xres, yres
	local xarea, yarea = xres*1.2, yres*1.2 -- want slightly larger area than screen so it's harder to notice repeated stars
	
	for i, star in ipairs(self.parallax) do
		-- calculate new positions
		local x = (star[1]-campos.x*star.depth) % xarea
		local y = (star[2]-campos.y*star.depth) % yarea
		if x >= 0 and x <= xres and y >= 0 and y <= yres then
			-- only draw if actually onscreen
			local color = self.colors[star.color]
			love.graphics.setColor(color[1], color[2], color[3], 128)
			love.graphics.draw(starimage, x, y, 0, star.size, star.size, 4, 4)
		end
	end
end