Matrix

--#filename:matrix-ss
--#version:0.8
--#author:Advert
-- Matrix screensaver v0.8
-- (C) 2012 User 'Advert' at http://www.computercraft.info/forums2/
-- X11/mit licence (use/modify at your will, but please, leave credit where due)
-- Spacebar to quit cleanly!
local mobj = {}
do -- Standart variables.
    mobj.x = 0
    mobj.y = 0 -- Offscreen
    mobj.lingerMin = 3 -- Minimum time to linger (frames)
    mobj.lingerMax = 10 -- Maximum time to linger
    mobj.linger = 10 -- How long this object will linger
    mobj.tailLenMin = 3 -- Minimum tail length
    mobj.tailLenMax = 10 -- Maximum tail length
    mobj.tailLen = 10
    mobj.chars = "1234567890-=!@#$%^&*()_+qwertyuiop[]QWERTYUIOP{}asdfghjkl;'\\ASDFGHJKL:\"|zxcvbnm,./ZXCVBNM<>?"
    mobj.charsLen = mobj.chars:len()
    mobj.currentTail = {"a", "a", "a", "a", "a", "a", "a", "a", "a", "a"}
    mobj.secretText = {}
    mobj.skipFrame = 0
    mobj.skipFrameMin = 1
    mobj.skipFrameMax = 3
    mobj.skipFrameMod = -1
    mobj.currFrame = 0
end

function mobj:new(o, ...)
    local o = o or {}
    setmetatable(o, self)
    self.__index = self
    o:__init(...)
    return o
end


function mobj:__init(x)
    self.linger = math.random(self.lingerMin, self.lingerMax)
    self.tailLen = math.random(self.tailLenMin, self.tailLenMax)
    self.x = x
    self.y = 1
    self.nFrame = 1
    self.currentTail = {}
    self.skipFrame = math.random(self.skipFrameMin, self.skipFrameMax) + self.skipFrameMod
end
function mobj:randomLinger()
    self.linger = math.random(self.lingerMin, self.lingerMax)
end
function mobj:printPos(x, y, sText)
    term.setCursorPos(x, y)
    term.write(sText)
end
function mobj:printPosT(x, y, sText)
    if self.secretText[y] and self.secretText[y][x] then
        sText = self.secretText[y][x]
    end
    return self:printPos(x, y, sText)
end
function mobj:randomChar()
    local r = math.random(1, self.charsLen)
    return string.sub(self.chars, r, r)
end
function mobj:printTail()
    for i = 1, self.tailLen do
        if not self.currentTail[i] then break end
        self:printPosT(self.x, self.y - i, self.currentTail[i])
    end
end

local termX, termY = term.getSize()
do
    for y = 1, termY do
        mobj.secretText[y] = {}
    end
    function mobj:addSecretText(x, y, sText)
        if sText:len() + x > termX then
            -- lolno.
        else
            for i = 1, sText:len() do
                local chr = sText:sub(i, i)
                self.secretText[y][x + i-1] = chr
            end
        end
    end
    function mobj:addSecretTextD(x, y, dir, sText)
        -- 1 = bottomright, 2 = bottomleft, 3 = topright, 4 = topleft
        local xmod = dir %2 == 1 and 1 or -1
        local ymod = (dir == 1 or dir == 2) and 1 or -1
        local finalx, finaly = x + (xmod * sText:len()), y + (ymod *sText:len())
        --print("finalx, finaly", finalx, finaly)
        --read()
        local cx, cy = x, y
        for i = 1, sText:len() do
            local cx, cy = x + (xmod * (i -1)), y + (ymod * (i -1))
            if self.secretText[cy] then
                self.secretText[cy][cx] = sText:sub(i, i)
            end
        end
    end

end

function mobj:render()
    self:printTail()
    local sSkip = false
    if self.currFrame ~= self.skipFrame then
        self.currFrame = self.currFrame + 1
    else
        self.currFrame = 0
        self.nFrame = self.nFrame + 1
        if self.nFrame == self.linger then
            table.insert(self.currentTail, 1, self.lastRandomChar)
            self:printPosT(self.x, self.y, self.currentTail[1])
            self.y = self.y + 1
            self.nFrame = 1
            if self.y > termY + self.tailLen then
                self:__init(self.x)
            end
            sSkip = true
        else
            self.lastRandomChar = self:randomChar()
        end
    end
    if not sSkip then
        self:printPos(self.x, self.y, self.lastRandomChar)
    end
end

local objects = {}
local eventT

function init()
    for i = 1, termX do
        objects[i] = mobj:new({}, i)
    end
    eventT = os.startTimer(0)
end

function render()
    term.clear()
    for _, k in pairs(objects) do
        k:render()
    end
end

mobj:addSecretTextD(15, 4, 1, "Casper7526")
mobj:addSecretTextD(18, 4, 1, "made me")
mobj:addSecretTextD(21, 4, 1, "do this.")
mobj:addSecretText(15, 15, "Spacebar to exit.")
init()

while true do
    local e, p1, p2 = os.pullEvent()
    if e == "timer" and p1 == eventT then
        eventT = os.startTimer(0.05) -- 20 fps
        render()
    elseif e == "key" and p1 == 57 then
        term.clear()
        term.setCursorPos(1,1)
        break
    end
end