Grav Jump

if not term.isColor() or not term.isColor then
    error("This game requires an advanced computer!")
end
local running = true
local maintimer = os.startTimer(0.09)
local randomtimer = 0
local platforms = {}

local gamestate = 0

local scroll = 0
local playingarea_y1 = 4
local playingarea_y2 = 19 - 4
local player_x = 1
local player_y = 1
local player_gravity = 0
local canchange = true
local meters = 0

local width, height = term.getSize()

function point_to_aabb(x, y, x2, y2, w2, h2)
    return (
        x >= x2 and
        x <= x2 + w2 and
        y >= y2 and
        y <= y2 + h2
    )
end

function _vertical_line_aabb(x, y1, y2, xb1, yb1, xbw, ybh)
    if y1 > y2 then
        return (
            x >= xb1 and
            x <= xb1 + xbw and
            y1 >= yb1 and
            y2 <= yb1 + ybh
        )
    else
        return (
            x >= xb1 and
            x <= xb1 + xbw and
            y2 >= yb1 and
            y1 <= yb1 + ybh
        )
    end
end
function vertical_line_aabb(x, y1, y2)
    for _, v in pairs(platforms) do
        if (_vertical_line_aabb(x, y1, y2, v.x, v.y, v.width, v.height)) then
            return true
        end
    end
    return false
end
function writeout(x, y, text, color)
    term.setCursorPos(x, y)
    term.setTextColor(color)
    term.write(text)
end
function createplatform(xx, yy, w, h)
    local platform = {x = xx; y = yy; width = w; height = h;}
    platform.color = 2 ^ math.random(1, 14)
    if platform.color == colors.lightBlue then
        while platform.color == colors.lightBlue do
            platform.color = 2 ^ math.random(1, 14)
        end
    end
    table.insert(platforms, platform)
end
function drawplayer()
    term.setCursorPos(player_x - scroll, player_y + playingarea_y1 - 1)
    term.setBackgroundColor(colors.white)
    term.setTextColor(colors.black)
    term.write((player_gravity == 0) and "v" or "^")
end

function moveplayer()
    player_x = player_x + 1
    scroll = scroll + 1
    if player_gravity == 0 then
        local down = false
        for _, v in pairs(platforms) do
            if point_to_aabb(player_x, player_y+1, v.x, v.y, v.width, v.height) then
                down = true
                break;
            end
        end
        player_y = player_y + ((down) and 0 or 1)
        for _, v in pairs(platforms) do
            if point_to_aabb(player_x, player_y + 1, v.x, v.y, v.width, v.height) or point_to_aabb(player_x, player_y, v.x, v.y, v.width, v.height) then
                player_y = v.y - 1
                canchange = true
                break;
            end
        end
    else
        local up = false
        for _, v in pairs(platforms) do
            if point_to_aabb(player_x, player_y, v.x, v.y, v.width, v.height) then
                up = true
                break;
            end
        end
        player_y = player_y - ((up) and 0 or 1)
        for _, v in pairs(platforms) do
            if point_to_aabb(player_x, player_y + 1, v.x, v.y, v.width, v.height) or point_to_aabb(player_x, player_y - 1, v.x, v.y, v.width, v.height) then
                player_y = v.y + 1
                canchange = true
                break;
            end
        end

    end
end

function drawplatform(platform)
    paintutils.drawFilledBox(platform.x - scroll, platform.y + playingarea_y1 - 1, platform.x + platform.width - scroll, platform.y + platform.height + playingarea_y1 - 2, platform.color)
end
function drawplatforms()
    for _, v in pairs(platforms) do
        drawplatform(v)
    end
end
local levelwidth = 51

local _random_dir = 0
local last_random_platform_x = 20
local last_random_platform_y = 8
local randomy = 0
function randomplatform()
    last_random_platform_y = randomy
    randomy = math.random(2, 10)

    while math.abs(randomy - last_random_platform_y) < 4 do
        randomy = math.random(2, 10)
    end

    createplatform(
                last_random_platform_x,
                randomy,
                math.random(4, 16),
                1
    )
    last_random_platform_x = platforms[#platforms].x + platforms[#platforms].width + math.random(0, 3)
    _random_dir = (_random_dir == 0) and 1 or 0
end

function initgame()
    meters = 0
    _random_dir = 0
    last_random_platform_x = 20
    term.clear()
    platforms = {}
    createplatform(4, 8, 16, 1)
    player_y = platforms[1].y - 1
    player_x = platforms[1].x + 1

    for i = 1, 6 do
        randomplatform()
    end

    player_gravity = 0
end
function initgamestart()
    meters = 0
    term.clear()
    player_y = platforms[1].y - 1
    player_x = platforms[1].x + 1

    player_gravity = 0
end
function updategame()
    if gamestate == 1 then
        moveplayer()
        meters = meters + 1
        if player_y > (playingarea_y2 - playingarea_y1)+2 or player_y < 0 then gamestate = 2 end
        randomtimer = randomtimer + 0.2
        if randomtimer >= 1 then
            randomplatform()
            randomtimer = 0
        end

    end
end
function drawgame()
    if gamestate == 0 then
        local title1 = "Grav"
        local title2 = "Jump"
        local start = "Press <SPACE> to start!"
        local quitstr = "Press <Q> to quit."

        paintutils.drawFilledBox(1, playingarea_y1 + 1, width, playingarea_y2 - 1, colors.lightBlue)
        paintutils.drawFilledBox(1, 1, width, playingarea_y1, colors.gray)
        paintutils.drawFilledBox(1, playingarea_y2, width, height, colors.gray)

        drawplatforms()
        drawplayer()
        term.setBackgroundColor(colors.gray)
        writeout(math.floor(width / 2) + 1, 2, title2, colors.red)
        writeout(math.floor(width / 2) - #title2, 2, title1, colors.lime)

        writeout(math.floor(width / 2) - math.floor(#quitstr / 2), height - 2, quitstr, colors.white)
        writeout(math.floor(width / 2) - math.floor(#start / 2), height - 3, start, colors.white)
    elseif gamestate == 1 then
        paintutils.drawFilledBox(1, playingarea_y1 + 1, width, playingarea_y2 - 1, colors.lightBlue)
        drawplatforms()
        drawplayer()

        paintutils.drawFilledBox(1, 1, width, playingarea_y1, colors.gray)
        paintutils.drawFilledBox(1, playingarea_y2, width, height, colors.gray)
        writeout(math.floor(width / 2) - math.ceil(#tostring(meters)/2), 2, tostring(meters), colors.white)

    elseif gamestate == 2 then
        local gameover = "You died!"
        local tryagain = "Try again?"
        local restart = "Press <SPACE> to restart!"
        local quit = "Press <Q> to quit."

        paintutils.drawFilledBox(1, playingarea_y1 + 1, width, playingarea_y2 - 1, colors.lightBlue)
        drawplatforms()

        term.setBackgroundColor(colors.lightBlue)
        writeout(math.ceil(width / 2) - math.ceil(#gameover / 2), math.floor(height / 2) - 2, gameover, colors.red)
        writeout(math.floor(width / 2) - math.floor(#tryagain / 2), math.floor(height / 2), tryagain, colors.red)
        writeout(math.floor(width / 2) - math.floor(#restart / 2), math.floor(height / 2) + 2, restart, colors.black)
        writeout(math.floor(width / 2) - math.floor(#quit / 2), math.floor(height / 2) + 3, quit, colors.black)

        paintutils.drawFilledBox(1, 1, width, playingarea_y1, colors.gray)
        paintutils.drawFilledBox(1, playingarea_y2, width, height, colors.gray)
        writeout(math.floor(width / 2) - math.ceil(#tostring(meters)/2), 2, tostring(meters), colors.white)
    end

end
function input(e)
    if gamestate == 0 then
        if e[1] == "key" then
            if e[2] == keys.space then
                scroll = 0
                initgamestart()
                gamestate = 1
                paintutils.drawFilledBox(1, playingarea_y1 + 1, width, playingarea_y2 - 1, colors.lightBlue)
            elseif e[2] == keys.q then
                running = false
            end

        end
    elseif gamestate == 1 then
        if e[1] == "key" then
            if e[2] == keys.space and (vertical_line_aabb(player_x, player_y, 16 * ((player_gravity == 0) and 1 or -1)) or vertical_line_aabb(player_x - 1, player_y, 16 * ((player_gravity == 0) and 1 or -1)) or vertical_line_aabb(player_x + 1, player_y, 16 * ((player_gravity == 0) and 1 or -1))) then
                if canchange then
                    player_gravity = (player_gravity == 0) and 1 or 0
                    canchange = false
                end
            end
        end
    elseif gamestate == 2 then
        if e[1] == "key" then
            if e[2] == keys.space then
                scroll = 0
                initgame()
                gamestate = 1
                paintutils.drawFilledBox(1, playingarea_y1 + 1, width, playingarea_y2 - 1, colors.lightBlue)
                math.randomseed(math.ceil(os.time() * 10))
            end
        end
    end
end

local mon = window.create(term.current(), 1, 1, width, height)
local oldterm = term.redirect(mon)

initgame()
while running do
    local e = {os.pullEvent()}
    input(e)
    if e[1] == "timer" then
        if e[2] == maintimer then
            updategame()
            mon.setVisible(true)
            mon.setVisible(false)
            drawgame()
            maintimer = os.startTimer(0.09)
        end
    elseif e[1] == "key" then
        if gamestate == 2 then
            if e[2] == keys.q then running = false; term.setCursorPos(1, 1); term.setBackgroundColor(colors.black); term.clear() end
        end
    end
end

term.redirect(oldterm)
local msg = "Thank you for playing GravJump!"
term.setBackgroundColor(colors.black)
term.clear()

if width < #msg then
    term.setCursorPos(1, 1)
    term.setTextColor(colors.blue)
    print(msg)
else
    writeout(math.floor(width / 2) - math.floor(#msg / 2), 1, msg, colors.blue)
    term.setCursorPos(1, 2)
end