private TerrainPatch( TerrainPatch parent, TerrainPatchVertices vertices, Point3 origin, Vector3 uAxis, Vector3 vAxis, float patchError, Point2 uv, float uvRes )
 {
     m_Parent = parent;
     m_Vertices = vertices;
     m_LocalOrigin = origin;
     m_LocalUAxis = uAxis;
     m_LocalVAxis = vAxis;
     m_Radius = ( uAxis + vAxis ).Length;
     m_PatchError = patchError;
     m_IncreaseDetailDistance = float.MaxValue;
     m_UvRes = uvRes;
     m_Uv = uv;
 }
 //    TODO: AP: UV patch resolution should be a function of patch size, not ply
 public TerrainPatch( TerrainPatchVertices vertices, Point3 origin, Vector3 uAxis, Vector3 vAxis, Point2 uv, float uvRes )
     : this(null, vertices, origin, uAxis, vAxis, float.MaxValue, uv, uvRes)
 {
 }