void vtLevel::GetEdgePlane(uint i, FPlane &plane)
{
vtEdge *edge = m_Edges[i];
int islope = edge->m_iSlope;
float slope = (islope / 180.0f * PIf);
int index = i;
int ring = m_LocalFootprint.WhichRing(index);
FLine3 &loop = m_LocalFootprint[ring];
uint ring_edges = loop.GetSize();
int next = (index+1 == ring_edges) ? 0 : index+1;
// get edge vector
FPoint3 vec = loop[next] - loop[index];
vec.Normalize();
// get perpendicular (upward pointing) vector
FPoint3 perp;
perp.Set(0, 1, 0);
// create rotation matrix to rotate it upward
FMatrix4 mat;
mat.Identity();
mat.AxisAngle(vec, slope);
// create normal
FPoint3 norm;
mat.TransformVector(perp, norm);
plane.Set(loop[index], norm);
}
