roguelike ascii tile display

rltiles.lua

local data = love.image.newImageData("Alloy_curses_12x12.png")
data:mapPixel(function(x,y,r,g,b,a)
	if r == 255 and b == 255 and g ~= 255 then
		r,g,b,a = 0,0,0,0
	end
	return r,g,b,a
end)
local img = love.graphics.newImage(data)

local spritebatch = love.graphics.newSpriteBatch(img, 87*25, "stream")
local quads = {}
for x = 0, 255 do
	local i,j = 1+(x%16), math.floor(x/16)
	quads[x] = love.graphics.newQuad(i*12, j*12, 12, 12, img:getWidth(), img:getHeight())
end

local random = math.random

local map = {}
local smap = {}
local old = {}
spritebatch:bind()
for i=0,86 do
	map[i] = {}
	smap[i] = {}
	old[i] = {}
	for j=0,24 do
		map[i][j] = random(255)
		old[i][j] = random(255)

		spritebatch:setColor(255,255,255)
		smap[i][j] = spritebatch:add(quads[map[i][j]], i*12, j*12)
	end	
end
spritebatch:unbind()

love.draw = function()
	spritebatch:bind()
	for i=0,86 do
		for j=0,24 do
			if map[i][j] ~= old[i][j] then
				old[i][j] = map[i][j]
				spritebatch:setColor(255,255,255)
				spritebatch:set(smap[i][j], quads[map[i][j]], i*12, j*12)
			end
		end
	end
	spritebatch:unbind()
	love.graphics.setColor(255,255,255,255)
	love.graphics.draw(spritebatch)
	love.graphics.print("FPS:"..love.timer.getFPS(),0,love.graphics.getHeight()-16)
end

love.update = function()
	if love.keyboard.isDown(" ") then
		for i=0,86 do
			for j=0,24 do
				map[i][j] = math.random(255)
			end
		end
	end
end