koobas.hobune.stream
Detect when UI element in canvas overlaps with moving game object and then make element follow object
Hello,
I'm using VR in Unity and have 3D game objects moving behind a UI canvas on which there's a raw image. The canvas and image render at a fixed location above everything else ("render mode" is "screen space" on a separate camera and layer). Basically it's like a HUD for VR. I would like, though, to detect when the raw image on that HUD overlaps with a specific game object that moves behind it and when that happens the image should lock and "follow" the object on the canvas plane until the user presses a key.
My idea to start implementing this was to cast a ray from the target game object to the camera and check whether it hits the image in the canvas, but I wasn't successful.
int uiLayer = LayerMask.NameToLayer("UI");
Ray raycast = new Ray(gameobject.transform.position, Camera.main.transform.position- gameobject.transform.position);
RaycastHit hit;
bool bHit = Physics.Raycast(raycast, out hit, Mathf.Infinity, uiLayer);
if (bHit)
{
var hitObj = hit.collider.gameObject;
if (hitObj == hudImage)
Debug.Log("HUD!");
}
I read in other answers that Physics.Raycast doesn't collide with 2D UI elements (even though I checked "raycast target" in the raw image script), but I'm not sure then how to achieve what I describe above.
Any help/code appreciated.
