Math3D.ProjectPointOnPlane C# (CSharp) Method

    public static Vector3 ProjectPointOnPlane(Vector3 planeNormal, Vector3 planePoint, Vector3 point)
    {
        float distance;
        Vector3 translationVector;

        //First calculate the distance from the point to the plane:
        distance = SignedDistancePlanePoint(planeNormal, planePoint, point);

        //Reverse the sign of the distance
        distance *= -1;

        //Get a translation vector
        translationVector = SetVectorLength(planeNormal, distance);

        //Translate the point to form a projection
        return point + translationVector;
    }

    void CalculateDistanceToMesh(Vector3 centerPoint, out float distance)
    {
        sqrShortestDistance = Mathf.Infinity;

        float   newSqrDistance;
        Vector3 nrml = Vector3.one;

        for (int i = 0; i < meshTriangles.Length; i += 3)
        {
            Vector3 p1 = filament.transform.TransformPoint(meshVertices[meshTriangles[i + 0]]);
            Vector3 p2 = filament.transform.TransformPoint(meshVertices[meshTriangles[i + 1]]);
            Vector3 p3 = filament.transform.TransformPoint(meshVertices[meshTriangles[i + 2]]);

            Vector3 edge1 = p1 - p2;
            Vector3 edge2 = p3 - p1;
            Vector3 edge3 = p2 - p3;


            Vector3 perp       = Vector3.Cross(edge1, edge2);
            float   perpLenght = perp.magnitude;
            Vector3 normal     = perp / perpLenght;

            Vector3 pointWithinPlane = Math3D.ProjectPointOnPlane(normal, p1, centerPoint);

            nrml = normal;

            float angleInTriangle1 = Vector3.Angle(p3 - p1, p2 - p1);
            float angleInTriangle2 = Vector3.Angle(p1 - p2, p3 - p2);
            float angleInTriangle3 = Vector3.Angle(p2 - p3, p1 - p3);

            float angleToPointInPlane1 = Math3D.SignedVectorAngle(edge2, pointWithinPlane - p1, normal) - 0; //180;
            angleToPointInPlane1 = (angleToPointInPlane1 < 0f ? angleToPointInPlane1 + 360f : angleToPointInPlane1);
            float angleToPointInPlane2 = Math3D.SignedVectorAngle(edge1, pointWithinPlane - p2, normal) - 0; //180;
            angleToPointInPlane2 = (angleToPointInPlane2 < 0f ? angleToPointInPlane2 + 360f : angleToPointInPlane2);
            float angleToPointInPlane3 = Math3D.SignedVectorAngle(edge3, pointWithinPlane - p3, normal) - 0; //180;
            angleToPointInPlane3 = (angleToPointInPlane3 < 0f ? angleToPointInPlane3 + 360f : angleToPointInPlane3);

            bool outOfTriangle = angleToPointInPlane1 > angleInTriangle1 || angleToPointInPlane2 > angleInTriangle2 || angleToPointInPlane3 > angleInTriangle3;

            if (!outOfTriangle)
            {
                newSqrDistance = (centerPoint - pointWithinPlane).sqrMagnitude;

                if (newSqrDistance < sqrShortestDistance)
                {
                    closestPoint                    = pointWithinPlane;
                    sqrShortestDistance             = newSqrDistance;
                    sphereDot[0].transform.position = closestPoint;
                    sphereDot[1].transform.position = new Vector3(10000f, 10000f, 10000f);
                    sphereDot[2].transform.position = new Vector3(10000f, 10000f, 10000f);
                }
            }
            else
            {
                projectionOnEdge[0] = Math3D.ProjectPointOnLineSegment(p2, p3, pointWithinPlane);
                projectionOnEdge[1] = Math3D.ProjectPointOnLineSegment(p3, p1, pointWithinPlane);
                projectionOnEdge[2] = Math3D.ProjectPointOnLineSegment(p1, p2, pointWithinPlane);

                for (int j = 0; j < 3; j++)
                {
                    newSqrDistance = (centerPoint - (projectionOnEdge[j])).sqrMagnitude;

                    if (newSqrDistance < sqrShortestDistance)
                    {
                        closestPoint        = projectionOnEdge[j];
                        sqrShortestDistance = newSqrDistance;


                        sphereDot[0].transform.position = projectionOnEdge[0];
                        sphereDot[1].transform.position = projectionOnEdge[1];
                        sphereDot[2].transform.position = projectionOnEdge[2];
                    }
                }
            }
        }

        distance = Mathf.Sqrt(sqrShortestDistance);
    }