Touch ID

Questions
1

How can I track the first touch on a screen. For example I have this program:

function setup()
    x=0
    y=0
end

function draw()
    background(0,0,0)
    fill(255,255,255)
    ellipse(CurrentTouch.x,CurrentTouch.y)
 end

However, it fails when another touch hits the screen. How can I only follow the first touch?

2

Try looking at the Multitouch example. You usually want to avoid CurrentTouch at all costs, because it brings up problems like this later on.

3

@austinmccoy Try this example. Drag the sprite around the screen while moving other fingers on the screen.


function setup()
    id=0
    pos=vec2(WIDTH/2,HEIGHT/2)
end

function draw()
    background(40, 40, 50)
    if pos.x+pos.y>0 then
        sprite("Planet Cute:Character Boy",pos.x,pos.y)
    end
end

function touched(t)
    if t.state==BEGAN and id==0 then
        id=t.id
        pos=vec2(t.x,t.y)
    end
    if t.state==MOVING and id==t.id then
        pos=vec2(t.x,t.y)
    end
    if t.state==ENDED and id==t.id then
        id=0       
    end
end
4

Thanks!

5

In your first if then loop in the touched function where you save the vector, I think you meant pos=vec2(t.x,t.y)

6

@austinmccoy You’re correct. I corrected it in the above code.