Exemplo n.º 1
0
    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;
    }
Exemplo n.º 2
0
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;
}