Need help with a joystick script

Unity Engine
1

Hi there,
I’m trying to make a joystick script that measures left right up and down. At the moment I am measuring the pointer’s position over a square area where x = 0 to 1 from left to right and y = 0 to 1 from botton to top.
This is working really well for placing graphics at the right spot and most things but I cant find a good way to measure when it is in each of the zones based on that x,y data.

so in the meantime I stuck with a patheticly lame script (please don’t mock me for it :slight_smile: ).

function RightButtonPosCheck(){
	if (RightButtonPosVector2.y >= .75)RightButtonPosition = 1;//Up	
	if (RightButtonPosVector2.y <= .25)RightButtonPosition = 3;//Down
	if (RightButtonPosVector2.x <= .25)RightButtonPosition = 4;//Left
	if (RightButtonPosVector2.x >= .75)RightButtonPosition = 2;//Right
}

Any way it works but it’s pretty crappy, does anyone have any good suggestions on how to detect when the pointer is in those zones. I just want it to feed bak a 1-4 value for me…

Thanks
Pete

2

  1. measure distance to center → radius. if larger than radius of the inner circle, you know you are in the zone

  2. use the angle of the direction center → touch in relation to “right” to define the sector ( Mathf.Sign(yPos - centerY)*acos( xPos - centerX), which gives you angle from 0 to ± 180 deg)

3

Woah, that was fast!
Cool thanks Dremora, That Sounds like the way to do it!
:smile:

4

Hey Dreamora,
Just trying to get this joystick script working and the distance part works fine but I’m having a little trouble getting the angle,

This is what I have so far -

(Mathf.Sign(HitPos.y - .5)) * (Mathf.Acos(HitPos.x - .5))

I’m not that great with this type of thing but I’m not sure how that would end up giving me a usable angle.

If you’ve got a sec could you point me in the right direction, sorry if I’m missing something obvious.

Pete

5

Acos() only returns an angle in the range [0, pi], as that’s all that can be determined from the cosine alone. The sign of the y coordinate is then used to determine whether the actual angle falls in the range [0, pi] or (-pi, 0).

However, I would just use Atan2() instead. That way you don’t have to worry about determining the sign, and you also don’t have to worry about the input falling outside the range [-1, 1] due to numerical imprecision (which may not be an issue here, but with Atan2() you’ll be safe either way).

6

Thanks!
I’ve put this formula in and it seems to be working well

RightJoysickAngle = (Mathf.Atan2((Pos.y - .5), (Pos.x - .5))* Mathf.Rad2Deg);
   if (RightJoysickAngle >= 45  RightJoysickAngle < 135) print ("1");
   if (RightJoysickAngle >= -45  RightJoysickAngle < 45) print ("2");
   if (RightJoysickAngle >= -135  RightJoysickAngle < -45) print ("3");
   if (RightJoysickAngle >= -180  RightJoysickAngle < -135 || RightJoysickAngle >= 135  RightJoysickAngle < 180) print ("4");
7

Something like that should work fine, but if you’re interested in cleaning it up a bit, here’s a little trick (C#, untested):

int ToIndex(float x, float y)
{
    float angle = (Mathf.Atan2(y, x) * Mathf.Rad2Deg) + 45f;
    if (angle < 0f) {
        angle += 360f;
    }
    return (int)(angle / 90f);
}

I use this method in my own code, although I may or may not have reproduced it here correctly (I think I got it right though).

8

ahh thanks man! That makes it heaps cleaner!