diff options
| -rw-r--r-- | xs/src/libslic3r/TriangleMesh.cpp | 117 |
1 files changed, 68 insertions, 49 deletions
diff --git a/xs/src/libslic3r/TriangleMesh.cpp b/xs/src/libslic3r/TriangleMesh.cpp index be554aef3..65a31fada 100644 --- a/xs/src/libslic3r/TriangleMesh.cpp +++ b/xs/src/libslic3r/TriangleMesh.cpp @@ -469,7 +469,7 @@ size_t TriangleMesh::number_of_patches() const facet_visited[facet_idx] = true; for (int j = 0; j < 3; ++ j) { int neighbor_idx = this->stl.neighbors_start[facet_idx].neighbor[j]; - if (! facet_visited[neighbor_idx]) + if (neighbor_idx != -1 && ! facet_visited[neighbor_idx]) facet_queue[facet_queue_cnt ++] = neighbor_idx; } } @@ -787,7 +787,7 @@ void TriangleMeshSlicer::slice(const std::vector<float> &z, std::vector<Polygons svg.Close(); } #if 0 -//FIXME the slice_facet() creates zero length edges. +//FIXME slice_facet() may create zero length edges due to rounding of doubles into coord_t. for (Polygon &poly : polygons) { for (size_t i = 1; i < poly.points.size(); ++ i) assert(poly.points[i-1] != poly.points[i]); @@ -888,15 +888,14 @@ TriangleMeshSlicer::FacetSliceType TriangleMeshSlicer::slice_facet( { IntersectionPoint points[3]; size_t num_points = 0; - size_t points_on_layer[3]; - size_t num_points_on_layer = 0; + size_t point_on_layer = size_t(-1); // Reorder vertices so that the first one is the one with lowest Z. // This is needed to get all intersection lines in a consistent order // (external on the right of the line) const int *vertices = this->mesh->stl.v_indices[facet_idx].vertex; - int i = (facet.vertex[1].z == min_z) ? 1 : ((facet.vertex[2].z == min_z) ? 2 : 0); - for (int j = i; j - i < 3; ++j) { // loop through facet edges + int i = (facet.vertex[1].z == min_z) ? 1 : ((facet.vertex[2].z == min_z) ? 2 : 0); + for (int j = i; j - i < 3; ++j) { // loop through facet edges int edge_id = this->facets_edges[facet_idx * 3 + (j % 3)]; int a_id = vertices[j % 3]; int b_id = vertices[(j+1) % 3]; @@ -1026,46 +1025,57 @@ TriangleMeshSlicer::FacetSliceType TriangleMeshSlicer::slice_facet( if (a->z == slice_z) { // Only point a alings with the cutting plane. - points_on_layer[num_points_on_layer ++] = num_points; - IntersectionPoint &point = points[num_points ++]; - point.x = a->x; - point.y = a->y; - point.point_id = a_id; + if (point_on_layer == size_t(-1) || points[point_on_layer].point_id != a_id) { + point_on_layer = num_points; + IntersectionPoint &point = points[num_points ++]; + point.x = a->x; + point.y = a->y; + point.point_id = a_id; + } } else if (b->z == slice_z) { // Only point b alings with the cutting plane. - points_on_layer[num_points_on_layer ++] = num_points; - IntersectionPoint &point = points[num_points ++]; - point.x = b->x; - point.y = b->y; - point.point_id = b_id; + if (point_on_layer == size_t(-1) || points[point_on_layer].point_id != b_id) { + point_on_layer = num_points; + IntersectionPoint &point = points[num_points ++]; + point.x = b->x; + point.y = b->y; + point.point_id = b_id; + } } else if ((a->z < slice_z && b->z > slice_z) || (b->z < slice_z && a->z > slice_z)) { // A general case. The face edge intersects the cutting plane. Calculate the intersection point. - IntersectionPoint &point = points[num_points ++]; - double t = (double(slice_z) - double(b->z)) / (double(a->z) - double(b->z)); - point.x = float(double(b->x) + (double(a->x) - double(b->x)) * t); - point.y = float(double(b->y) + (double(a->y) - double(b->y)) * t); - point.edge_id = edge_id; + assert(a_id != b_id); + // Sort the edge to give a consistent answer. + if (a_id > b_id) { + std::swap(a_id, b_id); + std::swap(a, b); + } + IntersectionPoint &point = points[num_points]; + double t = (double(slice_z) - double(b->z)) / (double(a->z) - double(b->z)); + if (t <= 0.) { + if (point_on_layer == size_t(-1) || points[point_on_layer].point_id != a_id) { + point.x = a->x; + point.y = a->y; + point_on_layer = num_points ++; + point.point_id = a_id; + } + } else if (t >= 1.) { + if (point_on_layer == size_t(-1) || points[point_on_layer].point_id != b_id) { + point.x = b->x; + point.y = b->y; + point_on_layer = num_points ++; + point.point_id = b_id; + } + } else { + point.x = coord_t(floor(double(b->x) + (double(a->x) - double(b->x)) * t + 0.5)); + point.y = coord_t(floor(double(b->y) + (double(a->y) - double(b->y)) * t + 0.5)); + point.edge_id = edge_id; + ++ num_points; + } } } - // We can't have only one point on layer because each vertex gets detected - // twice (once for each edge), and we can't have three points on layer, - // because we assume this code is not getting called for horizontal facets. - assert(num_points_on_layer == 0 || num_points_on_layer == 2); - if (num_points_on_layer > 0) { - assert(points[points_on_layer[0]].point_id == points[points_on_layer[1]].point_id); - assert(num_points == 2 || num_points == 3); - if (num_points < 3) - // This triangle touches the cutting plane with a single vertex. Ignore it. - return NoSlice; - // Erase one of the duplicate points. - -- num_points; - for (int i = points_on_layer[1]; i < num_points; ++ i) - points[i] = points[i + 1]; - } - - // Facets must intersect each plane 0 or 2 times. - assert(num_points == 0 || num_points == 2); + // Facets must intersect each plane 0 or 2 times, or it may touch the plane at a single vertex only. + assert(num_points < 3); if (num_points == 2) { line_out->edge_type = feGeneral; line_out->a = (Point)points[1]; @@ -1074,18 +1084,27 @@ TriangleMeshSlicer::FacetSliceType TriangleMeshSlicer::slice_facet( line_out->b_id = points[0].point_id; line_out->edge_a_id = points[1].edge_id; line_out->edge_b_id = points[0].edge_id; + // Not a zero lenght edge. + //FIXME slice_facet() may create zero length edges due to rounding of doubles into coord_t. + //assert(line_out->a != line_out->b); + // The plane cuts at least one edge in a general position. + assert(line_out->a_id == -1 || line_out->b_id == -1); + assert(line_out->edge_a_id != -1 || line_out->edge_b_id != -1); // General slicing position, use the segment for both slicing and object cutting. #if 0 - // In a degenerate case where a plane cuts the triangle very close to its vertex, it is possible, that - // a zero length edge is created. In that case the zero length edge could be safely ignored - // as the polyline will still be connected, because both the sliced edges of the triangle will be - // sliced the same way at the neighbor triangles. - return (line_out->a == line_out->b) ? NoSlice : Slicing; -#else - // The chaining code primarily relies on the IDs of the edges. - // Even though there may be a zero length edge generated, it is still important, - return Slicing; + if (line_out->a_id != -1 && line_out->b_id != -1) { + // Solving a degenerate case, where both the intersections snapped to an edge. + // Correctly classify the face as below or above based on the position of the 3rd point. + int i = vertices[0]; + if (i == line_out->a_id || i == line_out->b_id) + i = vertices[1]; + if (i == line_out->a_id || i == line_out->b_id) + i = vertices[2]; + assert(i != line_out->a_id && i != line_out->b_id); + line_out->edge_type = (this->v_scaled_shared[i].z < slice_z) ? feTop : feBottom; + } #endif + return Slicing; } return NoSlice; } @@ -1157,7 +1176,7 @@ static inline void remove_tangent_edges(std::vector<IntersectionLine> &lines) void TriangleMeshSlicer::make_loops(std::vector<IntersectionLine> &lines, Polygons* loops) const { #if 0 -//FIXME the slice_facet() creates zero length edges. +//FIXME slice_facet() may create zero length edges due to rounding of doubles into coord_t. //#ifdef _DEBUG for (const Line &l : lines) assert(l.a != l.b); |