Display canvas in front of player

Question

I have stuck in this simple problem but unable to understand that why i am unable to control it.

I have these line of code which is displaying my canvas object in front of my player(camRotationToWatch object name in code) at certain rotation of the player.

if (camRotationToWatch.transform.localEulerAngles.x >= navigationCanvasXMinmumLimit && camRotationToWatch.transform.localEulerAngles.x <= navigationCanvasXMaximumLimit)
        {
            if (!navCanvasHasDisplay) 
            {

                navigationCanvas.SetActive(true);
                //Debug.Log(camRotationToWatch.transform.forward);
                Vector3 navCanvas = camRotationToWatch.transform.position + camRotationToWatch.transform.forward * navCanvasDisplayDistanceFromCam;
                navCanvas = new Vector3(navCanvas.x, 2f, navCanvas.z);
                navigationCanvas.transform.position = new Vector3(navCanvas.x, navCanvas.y, navCanvas.z);

                navigationCanvas.transform.rotation = camRotationToWatch.transform.rotation;

                navCanvasHasDisplay = true;

            }
        }

        else
        {
            //navigationCanvas.SetActive(false);
            if (locationPanel.activeSelf == false && infoPanel.activeSelf == false) {
                navigationCanvas.SetActive(false);
                navCanvasHasDisplay = false;
            }
        }

This code is actually work fine when camRotationToWatch object rotate from down to up and Canvas show at correct position but as I try to to rotate camRotationToWatch from up to down it display(active) Canvas at very top position. How can I restrict canvas to show at same position (No matter player rotate from up to down or down to up) but display on front of the player object?

Answer 1

I believe the problem is that camRotationToWatch.transform.localEulerAngles.x may represent the angle in a way you are not expecting. For example, -30 degrees is the same as +330 degrees.

I'll take a guess that you are expecting a negative angle when looking up, while Unity is returning a positive angle. Try replacing the first line of the code you pasted with this code:

float xFromCamera = camRotationToWatch.transform.localEulerAngles.x;
if (xFromCamera >= 180.0f) xFromCamera -= 360.0f;
if (xFromCamera < -180.0f) xFromCamera += 360.0f;

if (xFromCamera >= navigationCanvasXMinmumLimit && xFromCamera <= navigationCanvasXMaximumLimit)

(Note: I wasn't confident at first, so I decided to test this out in Unity. I set the x rotation of a transform to a negative angle in code, then read the same x rotation later. The returned angle was positive, 360 + my angle.)