Touch ID

austinmccoy

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?

SkyTheCoder

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

dave1707

@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

austinmccoy

Thanks!

austinmccoy

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)

dave1707

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