jump button

Questions
1

So for my first practice project I have been making the first level in the arcade donkey kong. What I am stuck at now is making mario jump. I know there is an easy way of doing it in codea but I am not sure how. I kind of assume its has to do with the physics function (applyAngularImpulse but not sure).

Some guidance would be much appreciated

2

Here’s something I had.


supportedOrientations(LANDSCAPE_ANY)
displayMode(FULLSCREEN)

function setup()
    done=true
    cb={x=60,y=300}
    val=2
end

function jumpTween()
    t1=tween(.5,cb,{y=400},tween.easing.cubicOut)
    t2=tween(.5,cb,{y=300},tween.easing.cubicIn,tweenDone)
    tween.sequence(t1,t2)   
end

function duckTween()
    t1=tween(.5,cb,{y=200},tween.easing.cubicOut)
    t2=tween(.5,cb,{y=300},tween.easing.cubicIn,tweenDone)
    tween.sequence(t1,t2)   
end

function draw()
    background(40, 40, 50)
    fill(255)
    text("swipe up to jump, swipe down to duck",WIDTH/2,HEIGHT-100)
    rect(WIDTH/2,260,20,50)
    if cb.x<50 or cb.x>WIDTH-50 then    -- keep sprite on the screen
        val=-val
    end
    cb.x=cb.x+val -- move sprite 
    sprite("Planet Cute:Character Boy",cb.x,cb.y)    -- draw sprite
end

function tweenDone()
    done=true   -- tween is done, allow next jump or duck
end

function touched(t)
    if t.state==MOVING and done then
        done=false
        if t.deltaY<0 then  -- flick down
            duckTween()
        end
        if t.deltaY>0 then  -- flick up
            jumpTween()
        end
    end
end
3

Thank’s Dave for that. I think that is a bit too complicated for what I am thinking. For example, I wrote a function using a rectangle:
function setup()

x,y=0,0

end

function draw()

rect(x,y,50,50)

x=x+1

y=-1/5x(x-50)

this kind of does what I want but its a bit awkward to control.

Edit: I am going to play around with your’s Dave since I think its going to work much better than mine.

4

@velkroe - I’m afraid you’ll find that programming any non trivial game is quite complicated. This means your code can get tangled very quickly.

One thing I suggest is to break your code into little functions, as Dave has done, eg duckTween. I would even do that for the code in the draw function, eg have a function DrawLevel which draws the current level, MovePlayer, which moves the player, and so on.

5

@Ignatz: Yeah this is my first real game type program that I have ever tried writing (did some smaller php type stuff but nothing very significant). I really decided to write this program to learn more about coding and needed a project. I have been trying to break things up as much as possible but my code is still pretty cumbersome. My Main section is a little over 300 lines and my Mario class is about 150 lines. My other classes are really small and probably could have been better thought out. As I have written ideas have come on how I could better organize it and make it smaller. I really should be using functions more.

6

One thing to look for is where you either find you have code that repeats (put it into a function) or a function (like draw) that is trying to do lots of things.

A good rule is to have each function “do one thing well”. The more you break up your code into functions, the easier it is to test each of them.

I usually have an extra Test tab on the right with its own setup and draw functions, and I test each function on its own, using that tab. This is possible since Codea doesn’t mind your having more than one setup function - it will use the right hand one. So when are running your app normally, you comment out the test tab, or slide it to the left of the other tabs.

7

Oh I did not know that. I have been testing stuff out in a separate project. Your way will work much better.

8

Also, advice from the experts (which do not include me!) is to test as often as possible, so write a few lines, test, write a few lines, test…

The worst thing to do is just write the whole app and press Run.

9

The constant testing I do do.