public ShapeCache Cache(ConvexShape shape)
{
ShapeCache sc = (ShapeCache)shape.GetUserPointer();
if (sc == null)
{
sc = new ShapeCache(shape);
sc.m_shapehull.BuildHull(shape.GetMargin());
m_shapecaches.Add(sc);
shape.SetUserPointer(sc);
/* Build edges */
int ni = sc.m_shapehull.NumIndices();
int nv = sc.m_shapehull.NumVertices();
IList <int> pi = sc.m_shapehull.m_indices;
IList <IndexedVector3> pv = sc.m_shapehull.m_vertices;
IList <Edge> edges = new ObjectArray <Edge>(ni);
for (int i = 0; i < ni; i += 3)
{
IndexedVector3 nrm = IndexedVector3.Normalize(IndexedVector3.Cross(pv[pi[i + 1]] - pv[pi[i]], pv[pi[i + 2]] - pv[pi[i]]));
for (int j = 2, k = 0; k < 3; j = k++)
{
int a = pi[i + j];
int b = pi[i + k];
Edge e = edges[Math.Min(a, b) * nv + Math.Max(a, b)];
if (e != null)
{
sc.m_edges.Add(new Edge());
e = sc.m_edges[sc.m_edges.Count - 1];
e.n[0] = nrm; e.n[1] = -nrm;
e.v[0] = a; e.v[1] = b;
}
else
{
e.n[1] = nrm;
}
}
}
}
return(sc);
}
