[Bf-blender-cvs] [04ca6418f98] soc-2021-adaptive-cloth: adaptive_cloth: Mesh: support loose edges (read only)

[ishbosamiya]

Commit: 04ca6418f9852364bbe9afb9af7d9c7783fb3b5f
Author: ishbosamiya
Date:   Sat Jul 3 15:02:41 2021 +0530
Branches: soc-2021-adaptive-cloth
https://developer.blender.org/rB04ca6418f9852364bbe9afb9af7d9c7783fb3b5f

adaptive_cloth: Mesh: support loose edges (read only)

===================================================================

M	source/blender/blenkernel/BKE_cloth_remesh.hh
M	source/blender/blenkernel/tests/BKE_cloth_remesh_test.cc

===================================================================

diff --git a/source/blender/blenkernel/BKE_cloth_remesh.hh b/source/blender/blenkernel/BKE_cloth_remesh.hh
index 113ef7df497..017aa55b80e 100644
--- a/source/blender/blenkernel/BKE_cloth_remesh.hh
+++ b/source/blender/blenkernel/BKE_cloth_remesh.hh
@@ -893,11 +893,11 @@ template<typename END, typename EVD, typename EED, typename EFD> class Mesh {
 
   void read(const MeshIO &reader)
   {
-    const auto positions = reader.get_positions();
-    const auto uvs = reader.get_uvs();
-    const auto normals = reader.get_normals();
-    const auto face_indices = reader.get_face_indices();
-    const auto line_indices = reader.get_line_indices();
+    const auto &positions = reader.get_positions();
+    const auto &uvs = reader.get_uvs();
+    const auto &normals = reader.get_normals();
+    const auto &face_indices = reader.get_face_indices();
+    const auto &line_indices = reader.get_line_indices();
 
     /* TODO(ish): add support for when uvs doesn't exist */
     BLI_assert(uvs.size() != 0);
@@ -995,7 +995,66 @@ template<typename END, typename EVD, typename EED, typename EFD> class Mesh {
       }
     }
 
-    /* TODO(ish): add support for lines */
+    /* Add loose edges
+     *
+     * Need to create "empty" `Vert`(s) since `Edge`(s) store
+     * `Vert`(s) which has UV coords but since these are loose edges,
+     * they don't have any UV coords. Ideally we would store `Node`(s)
+     * directly but this might lead to problems else where with
+     * respect to speed (the link between edges and faces would be
+     * slower to access).
+     **/
+    {
+      /* For each loose edge, add the correct connectivity */
+      for (const auto &line : line_indices) {
+        blender::Vector<std::tuple<usize, usize>> line_pairs;
+        for (auto i = 0; i < line.size() - 1; i++) {
+          line_pairs.append(std::make_tuple(line[i], line[i + 1]));
+        }
+
+        for (const auto &[node_1_i, node_2_i] : line_pairs) {
+          auto &edge = this->add_empty_edge();
+
+          auto op_node_1 = this->nodes.get_no_gen(node_1_i);
+          BLI_assert(op_node_1);
+          auto &node_1 = op_node_1.value().get();
+
+          auto op_node_2 = this->nodes.get_no_gen(node_2_i);
+          BLI_assert(op_node_2);
+          auto &node_2 = op_node_2.value().get();
+
+          /* For `Node`(s) without `Vert`(s) create an empty vert */
+          {
+            auto connect_node_to_empty_vert = [this](auto &node) {
+              if (node.verts.size() == 0) {
+                auto &vert = this->add_empty_vert(float2_unknown());
+                vert.node = node.self_index;
+                node.verts.append(vert.self_index);
+              }
+            };
+
+            connect_node_to_empty_vert(node_1);
+            connect_node_to_empty_vert(node_2);
+          }
+
+          /* TODO(ish): in case `node_1` or `node_2` are part of a
+           * face, then it might make sense to pick the "best"
+           * `Vert`, maybe via distance?  */
+          /* Pick the first `Vert` of the `Node` to connect to loose edge */
+          auto op_vert_1 = this->verts.get(node_1.verts[0]);
+          BLI_assert(op_vert_1);
+          auto &vert_1 = op_vert_1.value().get();
+          auto op_vert_2 = this->verts.get(node_2.verts[0]);
+          BLI_assert(op_vert_2);
+          auto &vert_2 = op_vert_2.value().get();
+
+          /* Connect up the edge with the verts */
+          vert_1.edges.append(edge.self_index);
+          vert_2.edges.append(edge.self_index);
+          edge.verts = std::make_tuple(vert_1.self_index, vert_2.self_index);
+        }
+      }
+    }
 
     /* TODO(ish): ensure normal information properly, right now need
      * to just assume it is not dirty for faster development */
diff --git a/source/blender/blenkernel/tests/BKE_cloth_remesh_test.cc b/source/blender/blenkernel/tests/BKE_cloth_remesh_test.cc
index fa551c1f2fa..d634edc203b 100644
--- a/source/blender/blenkernel/tests/BKE_cloth_remesh_test.cc
+++ b/source/blender/blenkernel/tests/BKE_cloth_remesh_test.cc
@@ -842,6 +842,48 @@ TEST(cloth_remesh, Mesh_Read)
   }
 }
 
+TEST(cloth_remesh, Mesh_LooseEdges)
+{
+  MeshIO reader;
+  std::istringstream stream(plane_extra_loose_edges);
+  auto res = reader.read(std::move(stream), MeshIO::IOTYPE_OBJ);
+
+  EXPECT_TRUE(res);
+
+  Mesh<bool, bool, bool, bool> mesh;
+  mesh.read(reader);
+
+  const auto &nodes = mesh.get_nodes();
+  const auto &verts = mesh.get_verts();
+  const auto &edges = mesh.get_edges();
+  const auto &faces = mesh.get_faces();
+
+  EXPECT_EQ(nodes.size(), 14);
+  EXPECT_EQ(verts.size(), 14);
+  EXPECT_EQ(edges.size(), 17);
+  EXPECT_EQ(faces.size(), 1);
+
+  for (const auto &face : faces) {
+    EXPECT_EQ(face.get_verts().size(), 4);
+  }
+
+  for (const auto &edge : edges) {
+    auto num_faces = edge.get_faces().size();
+    EXPECT_TRUE(num_faces == 0 || num_faces == 1);
+  }
+
+  for (const auto &vert : verts) {
+    auto num_edges = vert.get_edges().size();
+    EXPECT_TRUE(num_edges >= 1 && num_edges <= 4);
+    EXPECT_NE(vert.get_node(), std::nullopt);
+  }
+
+  for (const auto &node : nodes) {
+    auto num_verts = node.get_verts().size();
+    EXPECT_EQ(num_verts, 1);
+  }
+}
+
 TEST(cloth_remesh, Mesh_Write)
 {
   MeshIO reader;