[SOLVED] Raycast hit.point is wrong | Brackeys Community | Page 1

floral skiff Mar 15, 2023, 3:44 PM

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Hey guys. I'm doing a raycast in a shape of the camera frustum, and trying to get the point where it intersects with the plane(ground). As you can see in the image, I got the rays working properly, but somehow the hit.point is returning a wrong position(the gizmos spheres represent the hit.point that it returns). The red lines are the rays. Any reason why this might be happening?? Any help would be appreciated

arctic fossil Mar 15, 2023, 3:47 PM

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Are you certain that the visualisation accurately represents the data?
How are you drawing the rays and the points, vs how are you doing the raycast itself

floral skiff Mar 15, 2023, 3:53 PM

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//FUNCTION DOING RAYCAST
//0 - topLeft. 1 - topRight, 2 - bottomLeft, 3 - bottomRight
    public Vector3[] GetFrustumCornersIntersectingGround(Camera cam, LayerMask groundLayer)
    {
        Vector3[] nearCorners = GetFrustumNearCorners(cam);
        Vector3[] farCorners = GetFrustumFarCorners(cam);
        Vector3[] intersectingPoints = new Vector3[4];
        for(int i = 0; i < intersectingPoints.Length; i++)
        {
            RaycastHit hit;
            if (Physics.Raycast(nearCorners[i], farCorners[i], out hit, Mathf.Infinity, groundLayer))
            {
                intersectingPoints[i] = hit.point;
            }
        }

        this.nearCorners = nearCorners;
        this.farCorners = farCorners;
        return intersectingPoints;
    }

//GIZMOS
private void OnDrawGizmosSelected()
    {
        Gizmos.color = Color.red;

        if(nearCorners!=null && nearCorners.Length >= 4)
        {
            for (int i = 0; i < nearCorners.Length; i++)
            {
                Gizmos.DrawLine(nearCorners[i], farCorners[i]);
            }
        }

        Vector3[] corners = GetFrustumCornersIntersectingGround(camera, groundLayer);
        for (int i = 0; i < corners.Length; i++)
        {
            Gizmos.DrawSphere(corners[i], 2f);
        }
    }

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Here are the two functions doing the raycast and the gizmos
Both are done from the same points

devout thistle Mar 16, 2023, 1:44 AM

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You know, in my experience when something doesn't line up like you think it should alot of times its because of something stupid in the inspector.

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is it parented to any other objects that could be warping its alignment?

floral skiff Mar 16, 2023, 4:40 AM

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I have fixed it 😃
Not sure what was the issue exactly, but as @arctic fossil said, the rays drawn by the gizmos are different from the actual raycasts.
Solution: I changed the raycasting method from:
if (Physics.Raycast(nearCorners[i], farCorners[i], out hit, Mathf.Infinity, groundLayer))
to

rays[i] = new Ray(nearCorners[i], farCorners[i] - nearCorners[i]);
RaycastHit hit;
if (Physics.Raycast(rays[i], out hit, Mathf.Infinity, groundLayer))

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Thanks guys @devout thistle @arctic fossil

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[SOLVED] Raycast hit.point is wrong

arctic fossil Mar 16, 2023, 11:19 AM

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floral skiff I have fixed it 😃 Not sure what was the issue exactly, but as <@94248427663130...

The issue was that you passed in a position for Raycast

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You treated it as Physics.Raycast(start, end) when that's wrong

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It's supposed to be Physics.Raycast(start, direction)

#[SOLVED] Raycast hit.point is wrong