ComputerCraft game api r5

--[[
place this file under .minecraft/mods/ComputerCraft/lua/rom/programs

to make a game with this api, make a new file and type shell.run('gameapi') at the top, the functions will then be available for you to use.

Breif Explanation of Functions:

actor:new(x, y, char[, bounded])
returns a new actor at the x and y positions on the terminal
bounded is a boolean which will determine whether or not your actor's movement is limited to the console window, true by default.

actor.x
the actor's x position

actor.y
the actor's y position

actor.char
the character representing the actor on screen

actor.bounded
whether or not the actor can go outside the screen

actor:setPos(x,y)
sets the actor's position
**this method and other positioning methods must be used in order for the actor's position to be updated onscreen

actor:addPos(x,y)
adds to the actor's position

actor:setX(n)
sets the actor's x position to n

actor:setY(n)
sets the actor's y position to n

actor:addX(n)
adds n to the actor's x position

actor:addY(n)
adds n to the actor's y position

actor:setChar(char)
change the actor's character to char

game.key(k)
user defined, triggered when a key is pressed

game.update()
user defined, triggered when a new frame is drawn

game.start()
required for the game to start, obviously
**any code after this function will not be ran until the game has stopped

game.stop()
quit the program

Example at http://pastebin.com/D78fft65

/*---*/

Changelog:

r1:
Released API

r4:
Added 'game:setChar()' to change an actor's characters
Added a 'bounded' attribute if you wanted an actor to be able to go outside the screen.
Added 'screen.width' and 'screen.height' as editable attributes to allow for custom widths and heights

r5:
Changed instructions for usage.
]]


term.clear()
print [[GameAPI r5
Press Backspace at any time to exit the game.]]

sleep(2)
screen = {}
screen.width = 40
screen.height = 15
screen.actors = {}

function round(v,int)
    local int = (int~=nil) and int or 1
    local n = v%int

    if n >= int/2 then
        return (v-n)+int
    else
        return (v-n)
    end
end

for y=1,screen.height do
    local t = {}
    for x=1,screen.width do
        table.insert(t,' ')
    end
    table.insert(screen.actors,t)
end

function draw()
    term.clear()
    for y,v in pairs(screen.actors) do
        local line = ''
        for x,vv in pairs(v) do
            line = line .. vv
        end
        print(line)
    end
end

function format(actor)
    if actor.bounded then
        actor.x = (actor.x>1) and actor.x or 1
        actor.x = (actor.x<screen.width) and actor.x or screen.width
        actor.y = (actor.y>1) and actor.y or 1
        actor.y = (actor.y<screen.height) and actor.y or screen.height
    end
    screen.actors[round(actor.y)][round(actor.x)] = actor.char
    return actor
end

actor = {}

function actor:new(x,y,char,b)
    actor.x = x
    actor.y = y
    actor.char = char
    actor.bounded = (b~=nil) and b or true
    screen.actors[round(y)][round(x)] = char
    return format(actor)
end

function actor:setPos(x,y)
    screen.actors[actor.y][actor.x] = ' '
    actor.x = x
    actor.y = y
    actor = format(actor)
end

function actor:setX(x)
    screen.actors[actor.y][actor.x] = ' '
    actor.x = x
    actor = format(actor)
end

function actor:setY(y)
    screen.actors[actor.y][actor.x] = ' '
    actor.y = y
    actor = format(actor)
end

function actor:addPos(x,y)
    screen.actors[actor.y][actor.x] = ' '
    actor.x = actor.x + x
    actor.y = actor.y + y
    actor = format(actor)
end

function actor:addX(x)
    screen.actors[actor.y][actor.x] = ' '
    actor.x = actor.x + x
    actor = format(actor)
end

function actor:addY(y)
    screen.actors[actor.y][actor.x] = ' '
    actor.y = actor.y + y
    actor = format(actor)
end

function actor:setChar(char)
    screen.actors[actor.y][actor.x] = char
    actor.char = char
end

function actor:destroy()
    screen.actors[actor.y][actor.x] = ' '
    actor = nil
end

game = {}
game.state = 'running'

function game.quit()
    term.clear()
    game.state = 'dead'
end

function game.start()
    os.startTimer(1/30)
    while game.state == 'running' do
        local t,k = os.pullEvent()
        if t == 'timer' then
            draw()
            if game.update ~= nil then game.update() end
            os.startTimer(1/30)
        elseif t == 'key' then
            if k == 14 then
                game.quit()
            else
                if game.key ~= nil then game.key(k) end
            end
        end
    end
end