Esempio n. 1
0
void TriContourGenerator::find_boundary_lines(Contour& contour,
                                              const double& level)
{
    // Traverse boundaries to find starting points for all contour lines that
    // intersect the boundaries.  For each starting point found, follow the
    // line to its end before continuing.
    const Triangulation& triang = get_triangulation();
    const Boundaries& boundaries = get_boundaries();
    for (Boundaries::const_iterator it = boundaries.begin();
            it != boundaries.end(); ++it) {
        const Boundary& boundary = *it;
        bool startAbove, endAbove = false;
        for (Boundary::const_iterator itb = boundary.begin();
                itb != boundary.end(); ++itb) {
            if (itb == boundary.begin())
                startAbove = get_z(triang.get_triangle_point(*itb)) >= level;
            else
                startAbove = endAbove;
            endAbove = get_z(triang.get_triangle_point(itb->tri,
                                                       (itb->edge+1)%3)) >= level;
            if (startAbove && !endAbove) {
                // This boundary edge is the start point for a contour line,
                // so follow the line.
                contour.push_back(ContourLine());
                ContourLine& contour_line = contour.back();
                TriEdge tri_edge = *itb;
                follow_interior(contour_line, tri_edge, true, level, false);
            }
        }
    }
}
Esempio n. 2
0
void TriContourGenerator::find_interior_lines(Contour& contour,
                                              const double& level,
                                              bool on_upper,
                                              bool filled)
{
    const Triangulation& triang = get_triangulation();
    int ntri = triang.get_ntri();
    for (int tri = 0; tri < ntri; ++tri) {
        int visited_index = (on_upper ? tri+ntri : tri);

        if (_interior_visited[visited_index] || triang.is_masked(tri))
            continue;  // Triangle has already been visited or is masked.

        _interior_visited[visited_index] = true;

        // Determine edge via which to leave this triangle.
        int edge = get_exit_edge(tri, level, on_upper);
        assert(edge >= -1 && edge < 3 && "Invalid exit edge");
        if (edge == -1)
            continue;  // Contour does not pass through this triangle.

        // Found start of new contour line loop.
        contour.push_back(ContourLine());
        ContourLine& contour_line = contour.back();
        TriEdge tri_edge = triang.get_neighbor_edge(tri, edge);
        follow_interior(contour_line, tri_edge, false, level, on_upper);

        if (!filled)
            // Non-filled contour lines must be closed.
            contour_line.push_back(contour_line.front());
        else if (contour_line.size() > 1 &&
                 contour_line.front() == contour_line.back())
            // Filled contour lines must not have same first and last points.
            contour_line.pop_back();
    }
}
Esempio n. 3
0
void TriContourGenerator::find_boundary_lines_filled(Contour& contour,
                                                     const double& lower_level,
                                                     const double& upper_level)
{
    // Traverse boundaries to find starting points for all contour lines that
    // intersect the boundaries.  For each starting point found, follow the
    // line to its end before continuing.
    const Triangulation& triang = get_triangulation();
    const Boundaries& boundaries = get_boundaries();
    for (Boundaries::size_type i = 0; i < boundaries.size(); ++i) {
        const Boundary& boundary = boundaries[i];
        for (Boundary::size_type j = 0; j < boundary.size(); ++j) {
            if (!_boundaries_visited[i][j]) {
                // z values of start and end of this boundary edge.
                double z_start = get_z(triang.get_triangle_point(boundary[j]));
                double z_end = get_z(triang.get_triangle_point(
                                   boundary[j].tri, (boundary[j].edge+1)%3));

                // Does this boundary edge's z increase through upper level
                // and/or decrease through lower level?
                bool incr_upper = (z_start < upper_level && z_end >= upper_level);
                bool decr_lower = (z_start >= lower_level && z_end < lower_level);

                if (decr_lower || incr_upper) {
                    // Start point for contour line, so follow it.
                    contour.push_back(ContourLine());
                    ContourLine& contour_line = contour.back();
                    TriEdge start_tri_edge = boundary[j];
                    TriEdge tri_edge = start_tri_edge;

                    // Traverse interior and boundaries until return to start.
                    bool on_upper = incr_upper;
                    do {
                        follow_interior(contour_line, tri_edge, true,
                            on_upper ? upper_level : lower_level, on_upper);
                        on_upper = follow_boundary(contour_line, tri_edge,
                                       lower_level, upper_level, on_upper);
                    } while (tri_edge != start_tri_edge);

                    // Filled contour lines must not have same first and last
                    // points.
                    if (contour_line.size() > 1 &&
                            contour_line.front() == contour_line.back())
                        contour_line.pop_back();
                }
            }
        }
    }

    // Add full boundaries that lie between the lower and upper levels.  These
    // are boundaries that have not been touched by an internal contour line
    // which are stored in _boundaries_used.
    for (Boundaries::size_type i = 0; i < boundaries.size(); ++i) {
        if (!_boundaries_used[i]) {
            const Boundary& boundary = boundaries[i];
            double z = get_z(triang.get_triangle_point(boundary[0]));
            if (z >= lower_level && z < upper_level) {
                contour.push_back(ContourLine());
                ContourLine& contour_line = contour.back();
                for (Boundary::size_type j = 0; j < boundary.size(); ++j)
                    contour_line.push_back(triang.get_point_coords(
                                      triang.get_triangle_point(boundary[j])));
            }
        }
    }
}