OVRRaycaster (Gaze UI) & GC Alloc

    static private Plane rectPlane = new Plane();
    static Vector3[] rectCorners = new Vector3[4];

    /// <summary>
    /// Detects whether a ray intersects a RectTransform and if it does also 
    /// returns the world position of the intersection.
    /// </summary>
    /// <param name="rectTransform"></param>
    /// <param name="ray"></param>
    /// <param name="worldPos"></param>
    /// <returns></returns>
    static bool RayIntersectsRectTransform(RectTransform rectTransform, Ray ray, out Vector3 worldPos)
    {

        rectTransform.GetWorldCorners(rectCorners);
        rectPlane.Set3Points(rectCorners[0], rectCorners[1], rectCorners[2]);

        float enter;
        if (!rectPlane.Raycast(ray, out enter))
        {
            worldPos = Vector3.zero;
            return false;
        }

        Vector3 intersection = ray.GetPoint(enter);

        Vector3 BottomEdge = rectCorners[3] - rectCorners[0];
        Vector3 LeftEdge = rectCorners[1] - rectCorners[0];
        float BottomDot = Vector3.Dot(intersection - rectCorners[0], BottomEdge);
        float LeftDot = Vector3.Dot(intersection - rectCorners[0], LeftEdge);
        if (BottomDot < BottomEdge.sqrMagnitude && // Can use sqrMag because BottomEdge is not normalized
            LeftDot < LeftEdge.sqrMagnitude &&
                BottomDot >= 0 &&
                LeftDot >= 0)
        {
            worldPos = rectCorners[0] + LeftDot * LeftEdge / LeftEdge.sqrMagnitude + BottomDot * BottomEdge / BottomEdge.sqrMagnitude;
            return true;
        }
        else
        {
            worldPos = Vector3.zero;
            return false;
        }
    }

"andyborrel" wrote:
Thanks for pointing this out. The allocations in this function are unnecessary. To fix this you can replace the function with the following version. Note the new static variables at the top of the snippet.

    static private Plane rectPlane = new Plane();
    static Vector3[] rectCorners = new Vector3[4];

    /// <summary>
    /// Detects whether a ray intersects a RectTransform and if it does also 
    /// returns the world position of the intersection.
    /// </summary>
    /// <param name="rectTransform"></param>
    /// <param name="ray"></param>
    /// <param name="worldPos"></param>
    /// <returns></returns>
    static bool RayIntersectsRectTransform(RectTransform rectTransform, Ray ray, out Vector3 worldPos)
    {

        rectTransform.GetWorldCorners(rectCorners);
        rectPlane.Set3Points(rectCorners[0], rectCorners[1], rectCorners[2]);

        float enter;
        if (!rectPlane.Raycast(ray, out enter))
        {
            worldPos = Vector3.zero;
            return false;
        }

        Vector3 intersection = ray.GetPoint(enter);

        Vector3 BottomEdge = rectCorners[3] - rectCorners[0];
        Vector3 LeftEdge = rectCorners[1] - rectCorners[0];
        float BottomDot = Vector3.Dot(intersection - rectCorners[0], BottomEdge);
        float LeftDot = Vector3.Dot(intersection - rectCorners[0], LeftEdge);
        if (BottomDot < BottomEdge.sqrMagnitude && // Can use sqrMag because BottomEdge is not normalized
            LeftDot < LeftEdge.sqrMagnitude &&
                BottomDot >= 0 &&
                LeftDot >= 0)
        {
            worldPos = rectCorners[0] + LeftDot * LeftEdge / LeftEdge.sqrMagnitude + BottomDot * BottomEdge / BottomEdge.sqrMagnitude;
            return true;
        }
        else
        {
            worldPos = Vector3.zero;
            return false;
        }
    }