Frustum Culling Problem

[Razor89]

Could anybody give me a hand on why this doesn't work? Thanks!

(Code is in VB.NET)

 

       Public Sub ExtractFrustumPlanes(Optional ByVal Normalize As Boolean = True)

           Dim comboMatrix As Matrix = Matrix.Multiply(ccCore.Device.Transform.View, ccCore.Device.Transform.Projection)

           'Left clipping plane
           ccFrustum(0).A = comboMatrix.M14 + comboMatrix.M11
           ccFrustum(0).B = -(comboMatrix.M24 + comboMatrix.M21)
           ccFrustum(0).C = -(comboMatrix.M34 + comboMatrix.M31)
           ccFrustum(0).D = -(comboMatrix.M44 + comboMatrix.M41)

           'Right clipping plane
           ccFrustum(1).A = -(comboMatrix.M14 - comboMatrix.M11)
           ccFrustum(1).B = -(comboMatrix.M24 - comboMatrix.M21)
           ccFrustum(1).C = -(comboMatrix.M34 - comboMatrix.M31)
           ccFrustum(1).D = -(comboMatrix.M44 - comboMatrix.M41)

           'Top clipping plane
           ccFrustum(2).A = -(comboMatrix.M14 - comboMatrix.M12)
           ccFrustum(2).B = -(comboMatrix.M24 - comboMatrix.M22)
           ccFrustum(2).C = -(comboMatrix.M34 - comboMatrix.M32)
           ccFrustum(2).D = -(comboMatrix.M44 - comboMatrix.M42)

           'Bottom clipping plane
           ccFrustum(3).A = -(comboMatrix.M14 + comboMatrix.M12)
           ccFrustum(3).B = -(comboMatrix.M24 + comboMatrix.M22)
           ccFrustum(3).C = -(comboMatrix.M34 + comboMatrix.M32)
           ccFrustum(3).D = -(comboMatrix.M44 + comboMatrix.M42)

           'Near clipping plane
           ccFrustum(4).A = -(comboMatrix.M14 + comboMatrix.M13)
           ccFrustum(4).B = -(comboMatrix.M24 + comboMatrix.M23)
           ccFrustum(4).C = -(comboMatrix.M34 + comboMatrix.M33)
           ccFrustum(4).D = -(comboMatrix.M44 + comboMatrix.M43)

           'Far clipping plane
           ccFrustum(5).A = -(comboMatrix.M14 - comboMatrix.M13)
           ccFrustum(5).B = -(comboMatrix.M24 - comboMatrix.M23)
           ccFrustum(5).C = -(comboMatrix.M34 - comboMatrix.M33)
           ccFrustum(5).D = -(comboMatrix.M44 - comboMatrix.M43)

           If Normalize Then
               For I As Integer = 0 To 5
                   ccFrustum(I).Normalize()
                   'NormalizePlane(ccFrustum(I))
               Next
           End If

       End Sub

 

       Public Function FrustumTestSphere(ByVal vCenter As m3dVector3D, ByVal Radius As Single) As Boolean

           Dim Distance As Single
           Dim tCenter As Vector3

           tCenter = vCenter.ToVector3
           tCenter.TransformCoordinate(ccCore.Device.Transform.World)

           For I As Integer = 0 To 5
               Distance = Plane.DotNormal(ccFrustum(I), tCenter)
               Debug.WriteLine(Distance)
               If Distance < -Radius Then
                   Return False
               End If
           Next

           Return True

       End Function

[PlausiblyDamp]

Could you give a hint as to what the problem is (or at least where it seems to be happening).