Bounce

levels = {}
levels['1'] = {}
levels['1']['x'] = 9
levels['1']['y'] = 9
levels['1']['map'] = {
    "#############################################################################",
    "#BSX                                                                        #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#                                                                           #",
    "#############################################################################"
}

ball = {}
ball['size'] = 1
ball['x'] = levels['1']['x']
ball['y'] = levels['1']['y']
ball['drawx'] = levels['1']['x']
ball['drawy'] = levels['1']['y']

scroll = {}
scroll['x'] = 0
scroll['y'] = 0

w, h = term.getSize()

function getChar(x, y)
    lvl = levels['1']['map'][y]
    print(lvl)
    if(lvl ~= nil)then
        char = string.sub(lvl, x, x)
        return char
    end
    return " "
end

function canMove(x, y, size)
    if(size == 1)then
        if(getChar(x, y) ~= " ")then
            return false
        end
    elseif(size == 2)then
        for u = 0, 1 do
            for d = 0, 1 do
                if(getChar(x+u, y+d) ~= " ")then
                    return false
                end
            end
        end
    end
    return true
end

function drawBall()
    term.clear()
    term.setBackgroundColor(colors.orange)
    if(ball['size'] == 1)then
        term.setCursorPos(ball['drawx'], ball['drawy']);
        term.write(" ")
    elseif(ball['size'] == 2)then
        term.setCursorPos(ball['drawx'], ball['drawy']);
        term.write("  ")
        term.setCursorPos(ball['drawx'], ball['drawy']+1);
        term.write("  ")
    end
    term.setBackgroundColor(colors.black)
end

function drawMap()
    for id, data in pairs(levels['1']['map']) do
        for f = 1, #data do
            char = string.sub(data, f, f)
            term.setCursorPos(f-scroll['x'], id-scroll['y'])
            if(char == "#")then
                term.setBackgroundColor(colors.yellow)
            elseif(char == "B")then
                term.setBackgroundColor(colors.lightBlue)
            elseif(char == "S")then
                term.setBackgroundColor(colors.pink)
            elseif(char == "X")then
                term.setBackgroundColor(colors.red)
            end
            if(char ~= " ")then
                term.write(" ")
            end
        end
    end
    term.setBackgroundColor(colors.black)
end

function checkScroll()
    if(#levels['1']['map'] > h)then
        if(ball['drawx'] < 25)then
            if(scroll['x'] > 0)then
                scroll['x'] = scroll['x'] - 1
                ball['drawx'] = 25
            end
        else
            calc = scroll['x'] + (scroll['x'] - ball['drawx']) + (scroll['x']+w-ball['drawx']) + 2
            if(string.sub(levels['1']['map'][ball['drawy']], calc, calc) ~= "")then
                if(w-ball['drawx'] == 25)then
                    scroll['x'] = scroll['x'] + 1
                    ball['drawx'] = 25
                end
            end
        end
    end
    if(#levels['1']['map'] > h)then
        if(ball['drawy'] < 9)then
            if(scroll['y'] > 0)then
                scroll['y'] = scroll['y'] - 1
                ball['drawy'] = 9
            end
        else
            if(levels['1']['map'][ball['y']+10] ~= nil)then
                if(h-ball['drawy'] == 9)then
                    scroll['y'] = scroll['y'] + 1
                    ball['drawy'] = 9
                end
            end
        end
    end
end

function drawScreen()
    checkScroll()
    drawBall()
    drawMap()
end

drawScreen()

while true do
    event, key = os.pullEvent("key")
    if key == 205 then
        if(canMove(ball['x']+1, ball['y'], ball['size']))then
            ball['x'] = ball['x'] + 1
            if(ball['x'] < 26)then
                ball['drawx'] = ball['x']
            else
                ball['drawx'] = ball['drawx'] + 1
            end
        end
    elseif key == 203 then
        if(canMove(ball['x']-1, ball['y'], ball['size']))then
            ball['x'] = ball['x'] - 1
            if(ball['x'] < 26)then
                ball['drawx'] = ball['x']
            else
                ball['drawx'] = ball['drawx'] - 1
            end
        end
    elseif key == 200 then
        if(canMove(ball['x'], ball['y']-1, ball['size']))then
            ball['y'] = ball['y'] - 1
            if(ball['y'] < 10)then
                ball['drawy'] = ball['y']
            else
                ball['drawy'] = ball['drawy'] - 1
            end
        end
    elseif key == 208 then
        if(canMove(ball['x'], ball['y']+1, ball['size']))then
            ball['y'] = ball['y'] + 1
            if(ball['y'] < 10)then
                ball['drawy'] = ball['y']
            else
                ball['drawy'] = ball['drawy'] + 1
            end
        end
    elseif key == 42 then
        if ball['size'] == 1 then
            if(canMove(ball['x'], ball['y'], ball['size']+1))then
                ball['size'] = 2
            end
        end
    elseif key == 29 then
        if ball['size'] == 2 then
            ball['size'] = 1
        end
    end
    drawScreen()
end