Triggering the pause function Codea has _ FIXED wrote some Lua code

Questions
21

Morning all. I’ve written the code in Lua this morning and have it fully working for pretty much 85% of objects. Just gotta go work through each class and it’s done. Thank you all

22

Maybe you can try coroutine, this is the example code:

function setup()
    pause = false
    -- Create a new coroutine for the function f
    co = coroutine.create(f)
    
    box = { x = 10, y = 10,
            width = 20, height = 20,
            fillColor = color(24, 28, 202, 255) }

    -- Here we can not use tween.
    -- t = tween(10, box, {x = 1000, y = 1000})
end

-- Put all your draw code in f
function f()
    while not pause do
        
        background()
        fontSize(40)
        fill(0,255,0)
        text(os.time(),WIDTH/2,HEIGHT/2)
        
        fill(box.fillColor)
        box.x, box.y = box.x+1,box.y+1
        rect(box.x,box.y,box.width,box.height)
        
        coroutine.yield()
    end
end

function draw()
    if not pause then
        coroutine.resume(co)
    end
end

function touched(t)
    -- Click left screen to pause, click right screen to resume
    if t.state == BEGAN and t.x >=WIDTH/2 then
        pause = false
    elseif t.state == BEGAN and t.x <WIDTH/2 then
        pause = true
    end
end

Using coroutine, good news is that you can control the flow exactly, bad news is that: 1) you need to control everything manually; 2) the performance will have to be affected.

23

Thanks @dave1707 and @binaryblues

The code I had in the end was a simple:

If pauser= false then

Which I would put around key parts in each class or functions that were increasing the game leveltimer - so when I hit a button for pause, pauser would be true.

It was dead easy in the end I was kicking myself!

Thanks

24

@Majormorgan I think it would be better to have a pause variable connected to the classes themselves. For example, if you want some things to stop (pause) and some others to continue there moving, you wouldn’t be able to, because it’s all connected to one variable. I think in the class, you should say for each object, if not self.paused then, followed by the code to move the object. Then when you want to pause everything,

for i,v in ipairs(table_containing_all_game_objects) then
   v.paused=true
end
25

Thanks @CamelCoder - that’s an awesome piece of code. I think when I come to make an update or new game I’ll use your code. Thanks!

26

@Majormorgan Instead of wrapping your code as you show above and what I show below, you can do something like what I show in the second and third part. You just have to add one line unless you want to do something special in a function when pauser is true.

-- Wrap the code like what you show above.
    if pauser==false then

        Code
        Code
        Code

    end

-- Don't wrap the code. Just add a single pause line to return.
    if pauser then return end

    Code
    Code
    Code

-- Don't wrap the code. If running special pause code, then return.
    if pauser then 
       pause code
       pause code
       return
   end

    Code
    Code
    Code
27

Thanks @dave1707 - so does return mean it goes back to the ‘if paused then’ part or back up to the top of then class?

It sounds cool. And could be something I use too.

The advantage I have with where the code is currently is when I pause you can still see the object on screen and it’s stopped too. This is because I wrap all the movement, shooting, hit detection and redrawing code within the ‘if pauser = true’ part. So it feels like a real paused moment.

That way, the drawing of the mesh is outside of that code enabling all the original on screen data like position, size, frame and art are drawn from the moment they were paused.

28

return means don’t execute anymore code in this function and to return to the calling function. Here’s a very simple example showing return.

displayMode(FULLSCREEN)

function setup()
    xr,yr=200,400
    xg,yg=100,600
    xrv,yrv=3,3
    xgv,ygv=2,2
    cnt=0
end

function draw()
    background(40, 40, 50)
    showText()
    updateRed()
    updateGreen()
end

function showText()
    -- show text
    fill(255)
    text("Tap screen to pause/unpause",WIDTH/2,HEIGHT-50)
    text(cnt,WIDTH/2,HEIGHT/2)
    
    if pause then return end    -- code to pause
    
    -- update count
    cnt=cnt+1
end

function updateRed()
    -- draw ellipse
    fill(255,0,0)
    ellipse(xr,yr,30)
    
    if pause then return end    -- code to pause
    
    -- update ellipse position
    xr=xr+xrv
    yr=yr+yrv
    if xr<0 or xr>WIDTH then
        xrv=xrv*-1
    end
    if yr<0 or yr>HEIGHT then
        yrv=yrv*-1
    end    
end

function updateGreen()
    -- draw ellipse
    fill(0,255,0)
    ellipse(xg,yg,30)
    
    if pause then return end    -- code to pause
    
    -- update ellipse position
    xg=xg+xgv
    yg=yg+ygv
    if xg<0 or xg>WIDTH then
        xgv=xgv*-1   end
    if yg<0 or yg>HEIGHT then
        ygv=ygv*-1
    end    
end

function touched(t)
    if t.state==BEGAN then
        pause=not pause
    end
end
29

@Majormorgan Basically what return does is it exits out of the function. To exit out of an if statement, there are a couple ways you can do it.
First way is to setup a one-time loop

for i=0,0 do
   if not pauser then
      --Then to end the if statement
      if shouldQuitIfStatement then break end
   end
end

Another way to do it is like @dave1707 did above, which is to split it up into multiple functions, which is highly recommended.

Lastly, you can use Lua’s goto function. The syntax gets a bit weird in this one.

local bool=true
::beforeIf::
if bool then
   if shouldQuitIfStatement then
      bool=false
      goto beforeIf
   end
end