From 9c1d0adc7775ec2352a0bf8b8d75ae9bc671e77c Mon Sep 17 00:00:00 2001
From: Philip Trettner <Philip.Trettner@rwth-aachen.de>
Date: Tue, 17 Jul 2018 15:51:18 +0200
Subject: [PATCH] working on optimization
---
src/polymesh/algorithms/optimization.hh | 12 +++++
src/polymesh/algorithms/topology.hh | 37 +++++++++++++++
src/polymesh/cursors.hh | 4 ++
src/polymesh/detail/union_find.hh | 60 +++++++++++++++++++++++++
4 files changed, 113 insertions(+)
create mode 100644 src/polymesh/algorithms/topology.hh
create mode 100644 src/polymesh/detail/union_find.hh
diff --git a/src/polymesh/algorithms/optimization.hh b/src/polymesh/algorithms/optimization.hh
index 05edc01..4e10659 100644
--- a/src/polymesh/algorithms/optimization.hh
+++ b/src/polymesh/algorithms/optimization.hh
@@ -4,6 +4,7 @@
#include "../detail/permutation.hh"
#include "../detail/random.hh"
+#include "../detail/union_find.hh"
namespace polymesh
{
@@ -62,6 +63,17 @@ inline void optimize_for_rendering(Mesh& m)
inline std::vector<int> cache_coherent_face_layout(Mesh const& m)
{
+ // build binary tree
+ // - approx min cut
+ // - refine approx
+ // - split
+
+ std::vector<std::pair<int, int>> edges;
+ for (auto e : m.edges())
+ edges.emplace_back((int)e.faceA(), (int)e.faceB());
+
+ // TODO
+
std::vector<int> id;
for (auto i = 0u; i < m.faces().size(); ++i)
id.push_back(i);
diff --git a/src/polymesh/algorithms/topology.hh b/src/polymesh/algorithms/topology.hh
new file mode 100644
index 0000000..88d434c
--- /dev/null
+++ b/src/polymesh/algorithms/topology.hh
@@ -0,0 +1,37 @@
+#pragma once
+
+#include <vector>
+
+#include "../Mesh.hh"
+
+namespace polymesh {
+
+/// Given a face handle, returns the topologically farthest (but finite) face
+/// (i.e. the last face that would be visited in a BFS)
+face_handle farthest_face(face_handle f);
+
+/// ======== IMPLEMENTATION ========
+
+/*inline face_handle farthest_face(face_handle f)
+{
+ std::vector<face_index> q_curr;
+ std::vector<face_index> q_next;
+
+ q_curr.push_back(f.idx);
+
+ face_handle last_f = f;
+
+ while (!q_curr.empty())
+ {
+ for (auto f : q_curr)
+ {
+ // TODO
+ }
+
+ std::swap(q_curr, q_next);
+ }
+
+ return last_f;
+}*/
+
+}
diff --git a/src/polymesh/cursors.hh b/src/polymesh/cursors.hh
index 635d166..7f93c51 100644
--- a/src/polymesh/cursors.hh
+++ b/src/polymesh/cursors.hh
@@ -31,6 +31,8 @@ struct primitive_index
bool operator==(handle_t const& rhs) const { return value == rhs.idx.value; }
bool operator!=(handle_t const& rhs) const { return value != rhs.idx.value; }
+ explicit operator int() const { return value; }
+
/// indexes this primitive by a functor
/// also works for attributes
/// - e.g. v[position] or f[area]
@@ -57,6 +59,8 @@ struct primitive_handle
bool operator==(handle_t const& rhs) const { return mesh == rhs.mesh && idx == rhs.idx; }
bool operator!=(handle_t const& rhs) const { return mesh != rhs.mesh || idx != rhs.idx; }
+ explicit operator int() const { return (int)idx; }
+
/// indexes this primitive by a functor
/// also works for attributes
/// - e.g. v[position] or f[area]
diff --git a/src/polymesh/detail/union_find.hh b/src/polymesh/detail/union_find.hh
new file mode 100644
index 0000000..c294bc8
--- /dev/null
+++ b/src/polymesh/detail/union_find.hh
@@ -0,0 +1,60 @@
+#pragma once
+
+#include <vector>
+
+namespace polymesh
+{
+namespace detail
+{
+struct disjoint_set
+{
+public:
+ disjoint_set(int size) : entries(size)
+ {
+ for (auto i = 0; i < size; ++i)
+ {
+ auto& e = entries[i];
+ e.parent = i;
+ e.size = 1;
+ }
+ }
+
+ int find(int idx)
+ {
+ auto& e = entries[idx];
+ if (e.parent != idx)
+ e.parent = find(e.parent);
+ return e.parent;
+ }
+
+ bool do_union(int x, int y)
+ {
+ // union by size
+ auto x_root = find(x);
+ auto y_root = find(y);
+
+ if (x_root == y_root)
+ return false;
+
+ if (entries[x_root].size < entries[y_root].size)
+ std::swap(x_root, y_root);
+ // |X| > |Y|
+
+ entries[y_root].parent = x_root;
+ entries[x_root].size += entries[y_root].size;
+
+ return true;
+ }
+
+private:
+ struct entry
+ {
+ int parent;
+ int size;
+ };
+
+private:
+ std::vector<entry> entries;
+};
+}
+}
--
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