From 45357d3771fa80163f7cd893e0f9215f7edee319 Mon Sep 17 00:00:00 2001
From: papush! <contact@ccolin.fr>
Date: Fri, 1 Oct 2021 10:07:54 +0200
Subject: [PATCH] refactor border finding code

---
 src/main_window.cpp     |  4 +++-
 src/mesh_processing.cpp | 29 ++++++++++++++++++++++++-----
 src/mesh_processing.h   |  8 +++++++-
 3 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/src/main_window.cpp b/src/main_window.cpp
index f3d3632..cbce79a 100644
--- a/src/main_window.cpp
+++ b/src/main_window.cpp
@@ -44,7 +44,9 @@ void MainWindow::open(const QString &path) {
 		mesh.set_color(vh, MyMesh::Color(0, 0, 0));
 	}
 	if (glm != nullptr) mesh_viewer.removeOpenGLMesh(glm);
- 	findHoles(mesh);
+ 	for (HalfedgeStrip border : findBorders(mesh)) {
+		setBorderColor(mesh, border, {1, 0, 0});
+	}
 	glm = mesh_viewer.addOpenGLMeshFromOpenMesh(&mesh);
 	for (QAction *a : toolbar_actions) {
 		a->setEnabled(true);
diff --git a/src/mesh_processing.cpp b/src/mesh_processing.cpp
index 6908aca..16261e5 100644
--- a/src/mesh_processing.cpp
+++ b/src/mesh_processing.cpp
@@ -1,11 +1,30 @@
 #include "mesh_processing.h"
+#include <list>
 
 
-void findHoles(MyMesh &mesh) {
-	for (const MyMesh::HalfedgeHandle &eh : mesh.halfedges()) {
-		if (mesh.is_boundary(eh)) {
-			MyMesh::VertexHandle vh = mesh.to_vertex_handle(eh);
-			mesh.set_color(vh, {.8, .2, .7});
+std::vector<HalfedgeStrip> findBorders(MyMesh &mesh) {
+	std::vector<HalfedgeStrip> borders(1);
+	size_t current = 0;
+	for (auto it = mesh.halfedges_begin(); it != mesh.halfedges_end(); ++it) {
+		while (mesh.is_boundary(*it)) {
+			borders[current].push_back(*it);
+			++it;
+		}
+		if (borders[current].size() > 0) {
+			borders.emplace_back();
+			current++;
 		}
 	}
+	if (borders.back().size() == 0) {
+		borders.pop_back();
+	}
+	return borders;
+}
+
+
+void setBorderColor(MyMesh &mesh, const HalfedgeStrip &border,
+					MyMesh::Color color) {
+	for (MyMesh::HalfedgeHandle it : border) {
+		mesh.set_color(mesh.to_vertex_handle(it), color);
+	}
 }
diff --git a/src/mesh_processing.h b/src/mesh_processing.h
index bc84b3f..aa7e786 100644
--- a/src/mesh_processing.h
+++ b/src/mesh_processing.h
@@ -3,8 +3,14 @@
 
 #include "my_mesh.h"
 
+#include <vector>
 
-void findHoles(MyMesh &mesh);
 
+typedef std::vector<MyMesh::HalfedgeHandle> HalfedgeStrip;
+
+std::vector<HalfedgeStrip> findBorders(MyMesh &mesh);
+
+void setBorderColor(MyMesh &mesh, const HalfedgeStrip &border,
+					MyMesh::Color color);
 
 #endif
\ No newline at end of file