From 05e2a831f44d56ab2a7cd5d36ff92f58a185929f Mon Sep 17 00:00:00 2001
From: Lukas Matena <lukasmatena@seznam.cz>
Date: Fri, 3 Jun 2022 12:53:34 +0200
Subject: [PATCH] Added some unit tests (SurfaceMesh)

---
 tests/libslic3r/CMakeLists.txt        |   1 +
 tests/libslic3r/test_surface_mesh.cpp | 122 ++++++++++++++++++++++++++
 2 files changed, 123 insertions(+)
 create mode 100644 tests/libslic3r/test_surface_mesh.cpp

diff --git a/tests/libslic3r/CMakeLists.txt b/tests/libslic3r/CMakeLists.txt
index a78720807..ed7d8a92b 100644
--- a/tests/libslic3r/CMakeLists.txt
+++ b/tests/libslic3r/CMakeLists.txt
@@ -26,6 +26,7 @@ add_executable(${_TEST_NAME}_tests
 	test_voronoi.cpp
     test_optimizers.cpp
     test_png_io.cpp
+    test_surface_mesh.cpp
     test_timeutils.cpp
     test_indexed_triangle_set.cpp
     test_astar.cpp
diff --git a/tests/libslic3r/test_surface_mesh.cpp b/tests/libslic3r/test_surface_mesh.cpp
new file mode 100644
index 000000000..34ff35667
--- /dev/null
+++ b/tests/libslic3r/test_surface_mesh.cpp
@@ -0,0 +1,122 @@
+#include <catch2/catch.hpp>
+#include <test_utils.hpp>
+
+
+#include <libslic3r/SurfaceMesh.hpp>
+
+using namespace Slic3r;
+
+
+// Generate a broken cube mesh. Face 8 is inverted, face 11 is missing.
+indexed_triangle_set its_make_cube_broken(double xd, double yd, double zd)
+{
+    auto x = float(xd), y = float(yd), z = float(zd);
+    return {
+        { {0, 1, 2}, {0, 2, 3}, {4, 5, 6}, {4, 6, 7},
+          {0, 4, 7}, {0, 7, 1}, {1, 7, 6}, {1, 6, 2},
+          {2, 5, 6}, {2, 5, 3}, {4, 0, 3}  /*missing face*/ },
+        { {x, y, 0}, {x, 0, 0}, {0, 0, 0}, {0, y, 0},
+          {x, y, z}, {0, y, z}, {0, 0, z}, {x, 0, z} }
+    };
+}
+
+
+
+TEST_CASE("SurfaceMesh on a cube", "[SurfaceMesh]") {
+    indexed_triangle_set cube = its_make_cube(1., 1., 1.);
+    SurfaceMesh sm(cube);
+    const Halfedge_index hi_first = sm.halfedge(Face_index(0));
+    Halfedge_index hi = hi_first;
+
+    REQUIRE(! hi_first.is_invalid());
+    
+    SECTION("next / prev halfedge") {
+        hi = sm.next(hi);
+        REQUIRE(hi != hi_first);
+        hi = sm.next(hi);
+        hi = sm.next(hi);
+        REQUIRE(hi == hi_first);
+        hi = sm.prev(hi);
+        REQUIRE(hi != hi_first);
+        hi = sm.prev(hi);
+        hi = sm.prev(hi);
+        REQUIRE(hi == hi_first);
+    }
+
+    SECTION("next_around_target") {
+        // Check that we get to the same halfedge after applying next_around_target
+        // four times.
+        const Vertex_index target_vert = sm.target(hi_first);
+        for (int i=0; i<4;++i) {
+            hi = sm.next_around_target(hi);
+            REQUIRE((hi == hi_first) == (i == 3));
+            REQUIRE(sm.is_same_vertex(sm.target(hi), target_vert));
+            REQUIRE(! sm.is_border(hi));
+        }
+    }
+
+    SECTION("iterate around target and source") {
+        hi = sm.next_around_target(hi);
+        hi = sm.prev_around_target(hi);
+        hi = sm.prev_around_source(hi);
+        hi = sm.next_around_source(hi);
+        REQUIRE(hi == hi_first);
+    }
+
+    SECTION("opposite") {
+        const Vertex_index target = sm.target(hi);
+        const Vertex_index source = sm.source(hi);
+        hi = sm.opposite(hi);
+        REQUIRE(sm.is_same_vertex(target, sm.source(hi)));
+        REQUIRE(sm.is_same_vertex(source, sm.target(hi)));
+        hi = sm.opposite(hi);
+        REQUIRE(hi == hi_first);
+    }
+
+    SECTION("halfedges walk") {
+        for (int i=0; i<4; ++i) {
+            hi = sm.next(hi);
+            hi = sm.opposite(hi);
+        }
+        REQUIRE(hi == hi_first);
+    }
+
+    SECTION("point accessor") {
+        Halfedge_index hi = sm.halfedge(Face_index(0));
+        hi = sm.opposite(hi);
+        hi = sm.prev(hi);
+        hi = sm.opposite(hi);
+        REQUIRE(hi.face() == Face_index(6));
+        REQUIRE(sm.point(sm.target(hi)).isApprox(cube.vertices[7])); 
+    }
+}
+
+
+
+
+TEST_CASE("SurfaceMesh on a broken cube", "[SurfaceMesh]") {
+    indexed_triangle_set cube = its_make_cube_broken(1., 1., 1.);
+    SurfaceMesh sm(cube);
+    
+    SECTION("Check inverted face") {
+        Halfedge_index hi = sm.halfedge(Face_index(8));
+        for (int i=0; i<3; ++i) {
+            REQUIRE(! hi.is_invalid());
+            REQUIRE(sm.is_border(hi));
+        }
+        REQUIRE(hi == sm.halfedge(Face_index(8)));
+        hi = sm.opposite(hi);
+        REQUIRE(hi.is_invalid());
+    }
+
+    SECTION("missing face") {
+        Halfedge_index hi = sm.halfedge(Face_index(0));
+        for (int i=0; i<3; ++i)
+            hi = sm.next_around_source(hi);
+        hi = sm.next(hi);
+        REQUIRE(sm.is_border(hi));
+        REQUIRE(! hi.is_invalid());
+        hi = sm.opposite(hi);
+        REQUIRE(hi.is_invalid());
+    }
+}