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Fix edge source not propagating distances to its extremities 

The fix is to change the way windows are created for edge sources : if it's
a border edge, then treat it as a face source; if it's a non border edge,
then do a 2-split of the face (each halfedge reaches 2 vertices, for a total
of 4 targets: 2 opposite, 2 incident)
This commit is contained in:
Mael Rouxel-Labbé 2022-07-05 15:39:29 +02:00
parent 64b9bbd9c6
commit 89b7bb125d
2 changed files with 119 additions and 68 deletions
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143
Surface_mesh_shortest_path/include/CGAL/Surface_mesh_shortest_path/Surface_mesh_shortest_path.h
View File

@ -830,42 +830,111 @@ private:
std::cout << "\t\tBoundary: " << is_border_edge(baseEdge, m_graph) << std::endl;
}
halfedge_descriptor baseEdges[2];
baseEdges[0] = baseEdge;
baseEdges[1] = opposite(baseEdge, m_graph);
Triangle_3 faces3d[2];
Triangle_2 layoutFaces[2];
for (std::size_t i = 0; i < 2; ++i)
{
faces3d[i] = triangle_from_halfedge(baseEdges[i]);
layoutFaces[i] = pt3t2(faces3d[i]);
}
Point_2 sourcePoints[2];
sourcePoints[0] = cb2(cv2(layoutFaces[0], 0), t0, cv2(layoutFaces[0], 1), t1);
sourcePoints[1] = cb2(cv2(layoutFaces[1], 0), t1, cv2(layoutFaces[1], 1), t0);
Cone_tree_node* edgeRoot = new Cone_tree_node(m_traits, m_graph, m_rootNodes.size());
node_created();
m_rootNodes.emplace_back(edgeRoot, sourcePointIt);
// If v0v1 is not a border edge:
//
// v2
// / \
// / \
// / \
// v0 - S - v1
// \ /
// \ /
// \ /
// v3
// The source S must reach all Vi, so for each side of the edge, there are two windwows being spawned:
// - v0v1 targetting v2 propagating only on the left (v0v2)
// - v2v0 targetting v1 propagating only on the left (v2v1)
// - v1v0 targetting v3 propagating only on the left (v1v3)
// - v3v1 targetting v0 propagating only on the left (v3v0)
//
// If v0v1 is a border edge, spawn 3 children in the face, and none on the other side
if(is_border_edge(baseEdge, m_graph))
{
const Face_location edgeSourceLocation = face_location(baseEdge, t0);
return expand_face_root(face(baseEdge, m_graph), edgeSourceLocation.second, sourcePointIt);
}
// From here on, it is not a border edge --> spawn 2 children on each side
halfedge_descriptor baseEdges[2];
baseEdges[0] = baseEdge;
baseEdges[1] = opposite(baseEdge, m_graph);
// shift is because the entry halfedge is not necessarily equal to halfedge(face(entry_h, g), g)
Barycentric_coordinates edgeSourceLocations[2];
edgeSourceLocations[0] = shifted_coordinates(face_location(baseEdges[0], t0).second,
Surface_mesh_shortest_paths_3::internal::edge_index(baseEdges[0], m_graph));
edgeSourceLocations[1] = shifted_coordinates(face_location(baseEdges[1], t1).second,
Surface_mesh_shortest_paths_3::internal::edge_index(baseEdges[1], m_graph));
for (std::size_t side = 0; side < 2; ++side)
{
Triangle_3 face3d(triangle_from_halfedge(baseEdges[side]));
Triangle_2 layoutFace(pt3t2(face3d));
Point_2 sourcePoint(construct_barycenter_in_triangle_2(layoutFace, edgeSourceLocations[side]));
// v0v1 targetting v2
if (m_debugOutput)
{
std::cout << "\tExpanding edge root #" << side << " : " << std::endl;;
std::cout << "\t\tFace = " << layoutFaces[side] << std::endl;
std::cout << "\t\tLocation = " << sourcePoints[side] << std::endl;
std::cout << std::endl << " ~~~~~~~~~~~~~~~~~~~~~~~~~~~" << std::endl;
std::cout << "\tExpanding edge root, side #" << side << ", targetting LOCAL 'v2'" << std::endl;
std::cout << "\t\t3D Face = " << face3d << std::endl;
std::cout << "\t\t2D Face = " << layoutFace << std::endl;
std::cout << "\t\tBarycentric coordinates: " << edgeSourceLocations[side][0]
<< " " << edgeSourceLocations[side][1]
<< " " << edgeSourceLocations[side][2] << std::endl;
std::cout << "\t\tLocation = " << sourcePoint << std::endl;
}
Cone_tree_node* mainChild = new Cone_tree_node(m_traits, m_graph, baseEdges[side], layoutFaces[side],
sourcePoints[side], FT(0), cv2(layoutFaces[side], 0),
cv2(layoutFaces[side], 1), Cone_tree_node::EDGE_SOURCE);
Cone_tree_node* v2_Child = new Cone_tree_node(m_traits, m_graph,
baseEdges[side] /*entryEdge*/,
layoutFace,
sourcePoint /*sourceImage*/,
FT(0) /*pseudoSourceDistance*/,
cv2(layoutFace, 0) /*windowLeft*/,
cv2(layoutFace, 2) /*windowRight*/,
Cone_tree_node::EDGE_SOURCE);
node_created();
edgeRoot->push_middle_child(mainChild);
process_node(mainChild);
edgeRoot->push_middle_child(v2_Child);
process_node(v2_Child);
// v2v0 targetting v1
face3d = triangle_from_halfedge(prev(baseEdges[side], m_graph));
layoutFace = pt3t2(face3d);
// shift the barycentric coordinates to correspond to the new layout
std::swap(edgeSourceLocations[side][1], edgeSourceLocations[side][2]);
std::swap(edgeSourceLocations[side][0], edgeSourceLocations[side][1]);
sourcePoint = Point_2(construct_barycenter_in_triangle_2(layoutFace, edgeSourceLocations[side]));
if (m_debugOutput)
{
std::cout << std::endl << " ~~~~~~~~~~~~~~~~~~~~~~~~~~~" << std::endl;
std::cout << "\tExpanding edge root, side #" << side << ", targetting LOCAL 'v1'" << std::endl;
std::cout << "\t\t3D Face = " << face3d << std::endl;
std::cout << "\t\t2D Face = " << layoutFace << std::endl;
std::cout << "\t\tBarycentric coordinates: " << edgeSourceLocations[side][0]
<< " " << edgeSourceLocations[side][1]
<< " " << edgeSourceLocations[side][2] << std::endl;
std::cout << "\t\tLocation = " << sourcePoint << std::endl;
}
Cone_tree_node* v1_Child = new Cone_tree_node(m_traits, m_graph,
prev(baseEdges[side], m_graph) /*entryEdge*/,
layoutFace,
sourcePoint /*sourceImage*/,
FT(0) /*pseudoSourceDistance*/,
cv2(layoutFace, 0) /*windowLeft*/,
cv2(layoutFace, 2) /*windowRight*/,
Cone_tree_node::EDGE_SOURCE);
node_created();
edgeRoot->push_middle_child(v1_Child);
process_node(v1_Child);
}
}
@ -1165,18 +1234,10 @@ private:
leftSide = node->has_left_side();
rightSide = node->has_right_side();
}
else // node corresponds to a source
else // source nodes only have left sides
{
if (node->node_type() == Cone_tree_node::EDGE_SOURCE)
{
leftSide = true;
rightSide = true;
}
else
{
leftSide = true;
rightSide = false;
}
leftSide = true;
rightSide = false;
}
if (m_debugOutput)
@ -1280,7 +1341,7 @@ private:
// This is a consequence of using the same basic node type for source and interval nodes
// If this is a source node, it is only pointing to one of the two opposite edges (the left one by convention)
if (node->node_type() != Cone_tree_node::INTERVAL && node->node_type() != Cone_tree_node::EDGE_SOURCE)
if (node->is_source_node())
{
propagateRight = false;
@ -1413,7 +1474,7 @@ private:
push_left_child(node);
}
if (propagateRight && (!node->is_source_node() || node->node_type() == Cone_tree_node::EDGE_SOURCE))
if (propagateRight)
{
CGAL_assertion(!node->is_source_node());
push_right_child(node);
@ -1706,7 +1767,6 @@ private:
switch (current->node_type())
{
case Cone_tree_node::INTERVAL:
case Cone_tree_node::EDGE_SOURCE:
{
const Segment_2& entrySegment = current->entry_segment();
const Point_2& currentSourceImage = current->source_image();
@ -1758,13 +1818,16 @@ private:
}
break;
case Cone_tree_node::VERTEX_SOURCE:
// This might be a pseudo source
visitor(target(current->entry_edge(), m_graph));
currentLocation = current->parent()->target_point();
current = current->parent();
break;
case Cone_tree_node::EDGE_SOURCE:
case Cone_tree_node::FACE_SOURCE:
// This is guaranteed to be the final node in any sequence
visitor(m_rootNodes[current->tree_id()].second->first, m_rootNodes[current->tree_id()].second->second);
visitor(m_rootNodes[current->tree_id()].second->first,
m_rootNodes[current->tree_id()].second->second);
current = current->parent();
break;
default:

44
Surface_mesh_shortest_path/include/CGAL/Surface_mesh_shortest_path/internal/Cone_tree.h
View File

@ -95,15 +95,22 @@ private:
public:
Cone_tree_node(const Traits& traits,
const Triangle_mesh& g,
const std::size_t treeId)
const halfedge_descriptor entryEdge,
const Triangle_2& layoutFace,
const Point_2& sourceImage,
const FT& pseudoSourceDistance,
const Point_2& windowLeft,
const Point_2& windowRight,
const Node_type nodeType = INTERVAL)
: m_traits(traits)
, m_graph(g)
, m_sourceImage(Point_2(CGAL::ORIGIN))
, m_layoutFace(Point_2(CGAL::ORIGIN),Point_2(CGAL::ORIGIN),Point_2(CGAL::ORIGIN))
, m_pseudoSourceDistance(0.0)
, m_level(0)
, m_treeId(treeId)
, m_nodeType(ROOT)
, m_entryEdge(entryEdge)
, m_sourceImage(sourceImage)
, m_layoutFace(layoutFace)
, m_pseudoSourceDistance(pseudoSourceDistance)
, m_windowLeft(windowLeft)
, m_windowRight(windowRight)
, m_nodeType(nodeType)
, m_leftChild(nullptr)
, m_rightChild(nullptr)
, m_pendingLeftSubtree(nullptr)
@ -135,27 +142,8 @@ public:
Cone_tree_node(const Traits& traits,
const Triangle_mesh& g,
const halfedge_descriptor entryEdge,
const Triangle_2& layoutFace,
const Point_2& sourceImage,
const FT& pseudoSourceDistance,
const Point_2& windowLeft,
const Point_2& windowRight,
const Node_type nodeType = INTERVAL)
: m_traits(traits)
, m_graph(g)
, m_entryEdge(entryEdge)
, m_sourceImage(sourceImage)
, m_layoutFace(layoutFace)
, m_pseudoSourceDistance(pseudoSourceDistance)
, m_windowLeft(windowLeft)
, m_windowRight(windowRight)
, m_nodeType(nodeType)
, m_leftChild(nullptr)
, m_rightChild(nullptr)
, m_pendingLeftSubtree(nullptr)
, m_pendingRightSubtree(nullptr)
, m_pendingMiddleSubtree(nullptr)
const std::size_t treeId)
: Cone_tree_node(traits, g, treeId, Graph_traits::null_halfedge())
{
}