bool ConvexHull2<Real>::Update ( Edge*& hull, int i )
{
// Locate an edge visible to the input point (if possible).
Edge* visible = 0;
Edge* current = hull;
do
{
if ( current->GetSign( i, mQuery ) > 0 )
{
visible = current;
break;
}
current = current->E[1];
}
while ( current != hull );
if ( !visible )
{
// The point is inside the current hull; nothing to do.
return true;
}
// Remove the visible edges.
Edge* adj0 = visible->E[0];
assertion( adj0 != 0, "Expecting nonnull adjacent\n" );
if ( !adj0 )
{
return false;
}
Edge* adj1 = visible->E[1];
assertion( adj1 != 0, "Expecting nonnull adjacent\n" );
if ( !adj1 )
{
return false;
}
visible->DeleteSelf();
while ( adj0->GetSign( i, mQuery ) > 0 )
{
hull = adj0;
adj0 = adj0->E[0];
assertion( adj0 != 0, "Expecting nonnull adjacent\n" );
if ( !adj0 )
{
return false;
}
adj0->E[1]->DeleteSelf();
}
while ( adj1->GetSign( i, mQuery ) > 0 )
{
hull = adj1;
adj1 = adj1->E[1];
assertion( adj1 != 0, "Expecting nonnull adjacent\n" );
if ( !adj1 )
{
return false;
}
adj1->E[0]->DeleteSelf();
}
// Insert the new edges formed by the input point and the end points of
// the polyline of invisible edges.
Edge* edge0 = new0 Edge( adj0->V[1], i );
Edge* edge1 = new0 Edge( i, adj1->V[0] );
edge0->Insert( adj0, edge1 );
edge1->Insert( edge0, adj1 );
hull = edge0;
return true;
}
bool ConvexHull2<Real>::Update (Edge*& rpkHull, int i)
{
// Locate an edge visible to the input point (if possible).
Edge* pkVisible = 0;
Edge* pkCurrent = rpkHull;
do
{
if (pkCurrent->GetSign(i,m_pkQuery) > 0)
{
pkVisible = pkCurrent;
break;
}
pkCurrent = pkCurrent->A[1];
}
while (pkCurrent != rpkHull);
if (!pkVisible)
{
// The point is inside the current hull; nothing to do.
return true;
}
// Remove the visible edges.
Edge* pkAdj0 = pkVisible->A[0];
assert(pkAdj0);
if (!pkAdj0)
{
return false;
}
Edge* pkAdj1 = pkVisible->A[1];
assert(pkAdj1);
if (!pkAdj1)
{
return false;
}
pkVisible->DeleteSelf();
while (pkAdj0->GetSign(i,m_pkQuery) > 0)
{
rpkHull = pkAdj0;
pkAdj0 = pkAdj0->A[0];
assert(pkAdj0);
if (!pkAdj0)
{
return false;
}
pkAdj0->A[1]->DeleteSelf();
}
while (pkAdj1->GetSign(i,m_pkQuery) > 0)
{
rpkHull = pkAdj1;
pkAdj1 = pkAdj1->A[1];
assert(pkAdj1);
if (!pkAdj1)
{
return false;
}
pkAdj1->A[0]->DeleteSelf();
}
// Insert the new edges formed by the input point and the end points of
// the polyline of invisible edges.
Edge* pkEdge0 = WM4_NEW Edge(pkAdj0->V[1],i);
Edge* pkEdge1 = WM4_NEW Edge(i,pkAdj1->V[0]);
pkEdge0->Insert(pkAdj0,pkEdge1);
pkEdge1->Insert(pkEdge0,pkAdj1);
rpkHull = pkEdge0;
return true;
}
