Get coordinate where touch occurred in box collider

[sunkas]

Is it possible to detect where a touch is happening in a box collider?

I need a button and ba able to detect where in it the touch is happening.

[ArenMook]

UICamera.currentTouch.pos tells you the screen position. UICamera.lastHit.point tells you the world position. You can calculate the rest from that.

[sunkas]

Thanks!

But what coordinate system does this position use? Any tip on how to convert this position into world coordinate or local coordinate?

[ArenMook]

That's the world position. Transform class has functions for transforming a world point to local coordinates.

[sunkas]

Are you sure it's world coordinates?

I tried this code on a onClick method on a button:

1. Vector3 worldTouchPos = UICamera.currentTouch.pos;
2. Vector3 localTouchPos = this.gameObject.transform.InverseTransformPoint (worldTouchPos);
3.                
4. Debug.Log ("worldTouchPos:"+ worldTouchPos);
5. Debug.Log ("localTouchPos:" + localTouchPos);
6. Debug.Log ("ButtonPos:"+this.transform.position);

And got the following result:

worldTouchPos:(299.0, 686.5, 0.0)
localTouchPos:(230072.3, 526616.3, -1206.2)
ButtonPos:(-0.6, 0.8, 1.6)

I assume ButtonPos is in world coordinates where the x and y are 0 to 1. InverseTransformPoint does accoding to docs "Transforms position from world space to local space." so I assume UICamera.currentTouch.pos is not world coordinates?

[Nicki]

UIcamera.currentTouch.pos is not world position. It's screen pixels.

I've just messed around with it a bunch, so while it may be a mistake, that's certainly what you get.

Do note that this is not affected by UIRoot or anything - it's just pixels on the screen, so iphone 4 is [(0,0), (960,640)]

[ArenMook]

Nicki is right. currentTouch.pos is in screen pixels. UICamera.lastHit.point is in world coordinates. My mistake.

[sunkas]

Thanks! UICamera.lastHit.point saved the day!