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Fix filtration after triangulation

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This commit is contained in:
Filip Sykala 2021-10-06 13:15:16 +02:00
parent ffba045734
commit 5aadd690be
1 changed files with 43 additions and 23 deletions
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66
src/libslic3r/Triangulation.cpp
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@ -24,7 +24,7 @@ inline void insert_edge(Slic3r::Triangulation::HalfEdges &edges, uint32_t &offse
offset += size;
}
}
} // namespace Private
Triangulation::Indices Triangulation::triangulate(const Points &points, const HalfEdges &half_edges)
{
@ -134,23 +134,37 @@ Triangulation::Indices Triangulation::triangulate(const ExPolygons &expolygons)
void Triangulation::remove_outer(Indices &indices, const HalfEdges &half_edges)
{
uint32_t no_triangle = indices.size();
// convert half edge to triangle index
std::map<HalfEdge, uint32_t> edge2triangle;
// triangles with all edges out of half_edge, candidate to remove
std::vector<uint32_t> triangles_to_check;
triangles_to_check.reserve(indices.size() / 3);
// triangle half edge
auto create_half_edge = [](const Vec3i& triangle, size_t index) {
size_t next_index = (index == 2) ? 0 : (index + 1);
return HalfEdge(triangle[index], triangle[next_index]);
};
// neighbor triangle half edge
auto create_opposit_half_edge = [](const Vec3i &triangle, size_t index) {
size_t prev_index = (index == 0) ? 2 : (index - 1);
return HalfEdge(triangle[index], triangle[prev_index]);
};
for (const auto &t : indices) {
uint32_t index = &t - &indices.front();
bool is_border = false;
for (size_t j = 0; j < 3; ++j) {
size_t j2 = (j == 0) ? 2 : (j - 1);
HalfEdge he(t[j2], t[j]);
HalfEdge he = create_half_edge(t, j);
if (half_edges.find(he) != half_edges.end())
is_border = true;
else
else {
assert(edge2triangle.find(he) == edge2triangle.end());
edge2triangle[he] = index;
}
}
if (!is_border) { triangles_to_check.push_back(index); }
if (!is_border) triangles_to_check.push_back(index);
}
std::set<uint32_t> remove;
@ -159,33 +173,39 @@ void Triangulation::remove_outer(Indices &indices, const HalfEdges &half_edges)
auto it = remove.find(index);
if (it != remove.end()) continue; // already removed
bool is_edge = false;
const Vec3i &t = indices[index];
bool is_edge = false;
const Vec3i &t = indices[index];
// check if exist opposit triangle
for (size_t j = 0; j < 3; ++j) {
size_t j2 = (j == 0) ? 2 : (j - 1);
// opposit
HalfEdge he(t[j], t[j2]);
if (edge2triangle.find(he) == edge2triangle.end()) is_edge = true;
HalfEdge he = create_opposit_half_edge(t, j);
auto it = edge2triangle.find(he);
if (it == edge2triangle.end()) {
is_edge = true;
break;
}
assert(it->second != index);
}
if (!is_edge) continue; // correct
// when there is no opposit edge, remove triangle and all neighbors recursive
insert.push(index);
while (!insert.empty()) {
uint32_t i = insert.front();
do {
uint32_t triangle_index = insert.front();
insert.pop();
if (remove.find(i) != remove.end()) continue;
remove.insert(i);
if (remove.find(triangle_index) != remove.end()) continue; // already removed
remove.insert(triangle_index);
for (size_t j = 0; j < 3; ++j) {
size_t j2 = (j == 0) ? 2 : (j - 1);
// opposit
HalfEdge he(t[j], t[j2]);
const Vec3i &t = indices[triangle_index];
HalfEdge he = create_opposit_half_edge(t, j);
auto it = edge2triangle.find(he);
if (it == edge2triangle.end()) continue; // edge
insert.push(it->second);
if (it == edge2triangle.end()) continue; // edge triangle without neighbor
// process neighbor
uint32_t neighbor_index = it->second;
assert(neighbor_index != triangle_index);
insert.push(neighbor_index);
}
}
} while (!insert.empty());
}
// remove indices