Add IO for NPZ files for Tensor-based TriangleMeshes (#6019)

* Add IO to/from NPZ files

* Add texture maps and generic attriubtes to IO

* Style fixes

* Read/write material name and fix read with metallic texture

* Add unit test for TriangleMesh NPZ IO

* Apply style fixes

* Rename uvmap to triangle_texture_uvs

* Style fixes

cpp/open3d/t/io/TriangleMeshIO.cpp

@@ -7,8 +7,10 @@
 
 #include "open3d/t/io/TriangleMeshIO.h"
 
+#include <set>
 #include <unordered_map>
 
+#include "open3d/t/io/NumpyIO.h"
 #include "open3d/utility/FileSystem.h"
 #include "open3d/utility/Logging.h"
 
@@ -22,6 +24,7 @@ static const std::unordered_map<
  geometry::TriangleMesh &,
  const open3d::io::ReadTriangleMeshOptions &)>>
  file_extension_to_trianglemesh_read_function{
+ {"npz", ReadTriangleMeshFromNPZ},
  {"stl", ReadTriangleMeshUsingASSIMP},
  {"obj", ReadTriangleMeshUsingASSIMP},
  {"off", ReadTriangleMeshUsingASSIMP},
@@ -40,7 +43,9 @@ static const std::unordered_map<
  const bool,
  const bool,
  const bool)>>
- file_extension_to_trianglemesh_write_function{};
+ file_extension_to_trianglemesh_write_function{
+ {"npz", WriteTriangleMeshToNPZ},
+ };
 
 std::shared_ptr<geometry::TriangleMesh> CreateMeshFromFile(
  const std::string &filename, bool print_progress) {
@@ -137,6 +142,160 @@ bool WriteTriangleMesh(const std::string &filename,
  return success;
 }
 
+bool ReadTriangleMeshFromNPZ(
+ const std::string &filename,
+ geometry::TriangleMesh &mesh,
+ const open3d::io::ReadTriangleMeshOptions &params) {
+ auto attribute_map = ReadNpz(filename);
+
+ // At a minimum there should be 'vertices' and 'triangles'
+ if (!(attribute_map.count("vertices") > 0) ||
+ !(attribute_map.count("triangles") > 0)) {
+ utility::LogWarning(
+ "Read geometry::TriangleMesh failed: Could not find 'vertices' "
+ "or 'triangles' attributes in {}",
+ filename);
+ return false;
+ }
+
+ // Fill mesh with attributes
+ for (auto &attr : attribute_map) {
+ if (attr.first == "vertices") {
+ mesh.SetVertexPositions(attr.second);
+ } else if (attr.first == "triangles") {
+ mesh.SetTriangleIndices(attr.second);
+ } else if (attr.first == "vertex_normals") {
+ mesh.SetVertexNormals(attr.second);
+ } else if (attr.first == "triangle_normals") {
+ mesh.SetTriangleNormals(attr.second);
+ } else if (attr.first == "vertex_colors") {
+ mesh.SetVertexColors(attr.second);
+ } else if (attr.first == "triangle_colors") {
+ mesh.SetTriangleColors(attr.second);
+ } else if (attr.first == "triangle_texture_uvs") {
+ mesh.SetTriangleAttr("texture_uvs", attr.second);
+ } else if (attr.first.find("tex_") != std::string::npos) {
+ // Get texture map
+ auto key = attr.first.substr(4);
+ if (!mesh.GetMaterial().IsValid()) {
+ mesh.GetMaterial().SetDefaultProperties();
+ }
+ mesh.GetMaterial().SetTextureMap(key, geometry::Image(attr.second));
+ // Note: due to quirk of Open3D shader implementation if we have a
+ // metallic texture we need to set the metallic scalar propert to
+ // 1.0
+ if (key == "metallic") {
+ mesh.GetMaterial().SetScalarProperty("metallic", 1.0);
+ }
+ } else if (attr.first.find("vertex_") != std::string::npos) {
+ // Generic vertex attribute
+ auto key = attr.first.substr(7);
+ mesh.SetVertexAttr(key, attr.second);
+ } else if (attr.first.find("triangle_") != std::string::npos) {
+ // Generic triangle attribute
+ auto key = attr.first.substr(9);
+ mesh.SetTriangleAttr(key, attr.second);
+ } else if (attr.first == "material_name") {
+ if (!mesh.GetMaterial().IsValid()) {
+ mesh.GetMaterial().SetDefaultProperties();
+ }
+ const uint8_t *str_ptr = attr.second.GetDataPtr<uint8_t>();
+ std::string mat_name(attr.second.GetShape().GetLength(), 'a');
+ std::memcpy((void *)mat_name.data(), str_ptr,
+ attr.second.GetShape().GetLength());
+ mesh.GetMaterial().SetMaterialName(mat_name);
+ }
+ }
+
+ return true;
+}
+
+bool WriteTriangleMeshToNPZ(const std::string &filename,
+ const geometry::TriangleMesh &mesh,
+ const bool write_ascii,
+ const bool compressed,
+ const bool write_vertex_normals,
+ const bool write_vertex_colors,
+ const bool write_triangle_uvs,
+ const bool print_progress) {
+ // Sanity checks...
+ if (write_ascii) {
+ utility::LogWarning(
+ "TriangleMesh can't be saved in ASCII fromat as .npz");
+ return false;
+ }
+ if (compressed) {
+ utility::LogWarning(
+ "TriangleMesh can't be saved in compressed format as .npz");
+ return false;
+ }
+
+ // Map attribute names to names already used by convention in other software
+ std::set<std::string> known_attributes(
+ {"positions", "normals", "texture_uvs", "indices", "colors"});
+
+ // Build map of known attributes
+ std::unordered_map<std::string, core::Tensor> mesh_attributes;
+ if (mesh.HasVertexPositions()) {
+ mesh_attributes["vertices"] = mesh.GetVertexPositions();
+ }
+ if (mesh.HasVertexNormals()) {
+ mesh_attributes["vertex_normals"] = mesh.GetVertexNormals();
+ }
+ if (mesh.HasVertexColors()) {
+ mesh_attributes["vertex_colors"] = mesh.GetVertexColors();
+ }
+ if (mesh.HasTriangleIndices()) {
+ mesh_attributes["triangles"] = mesh.GetTriangleIndices();
+ }
+ if (mesh.HasTriangleNormals()) {
+ mesh_attributes["triangle_normals"] = mesh.GetTriangleNormals();
+ }
+ if (mesh.HasTriangleColors()) {
+ mesh_attributes["triangle_colors"] = mesh.GetTriangleColors();
+ }
+ if (mesh.HasTriangleAttr("texture_uvs")) {
+ mesh_attributes["triangle_texture_uvs"] =
+ mesh.GetTriangleAttr("texture_uvs");
+ }
+
+ // Add "generic" attributes
+ for (auto attr : mesh.GetVertexAttr()) {
+ if (known_attributes.count(attr.first) > 0) {
+ continue;
+ }
+ std::string key_name("vertex_");
+ key_name += attr.first;
+ mesh_attributes[key_name] = attr.second;
+ }
+ for (auto attr : mesh.GetTriangleAttr()) {
+ if (known_attributes.count(attr.first) > 0) {
+ continue;
+ }
+ std::string key_name("triangle_");
+ key_name += attr.first;
+ mesh_attributes[key_name] = attr.second;
+ }
+
+ // Output texture maps
+ if (mesh.GetMaterial().IsValid()) {
+ auto &mat = mesh.GetMaterial();
+ // Get material name in Tensor form
+ std::vector<uint8_t> mat_name_vec(
+ {mat.GetMaterialName().begin(), mat.GetMaterialName().end()});
+ core::Tensor mat_name_tensor(std::move(mat_name_vec));
+ mesh_attributes["material_name"] = mat_name_tensor;
+ for (auto &tex : mat.GetTextureMaps()) {
+ std::string key = std::string("tex_") + tex.first;
+ mesh_attributes[key] = tex.second.AsTensor();
+ }
+ }
+
+ WriteNpz(filename, mesh_attributes);
+
+ return true;
+}
+
 } // namespace io
 } // namespace t
 } // namespace open3d

cpp/open3d/t/io/TriangleMeshIO.h

@@ -54,6 +54,19 @@ bool ReadTriangleMeshUsingASSIMP(
  geometry::TriangleMesh &mesh,
  const open3d::io::ReadTriangleMeshOptions &params);
 
+bool ReadTriangleMeshFromNPZ(const std::string &filename,
+ geometry::TriangleMesh &mesh,
+ const open3d::io::ReadTriangleMeshOptions &params);
+
+bool WriteTriangleMeshToNPZ(const std::string &filename,
+ const geometry::TriangleMesh &mesh,
+ const bool write_ascii,
+ const bool compressed,
+ const bool write_vertex_normals,
+ const bool write_vertex_colors,
+ const bool write_triangle_uvs,
+ const bool print_progress);
+
 } // namespace io
 } // namespace t
 } // namespace open3d

cpp/tests/t/io/TriangleMeshIO.cpp

@@ -71,6 +71,20 @@ TEST(TriangleMeshIO, ReadWriteTriangleMeshOBJ) {
  EXPECT_TRUE(mesh.GetTriangleIndices().AllClose(triangles));
 }
 
+TEST(TriangleMeshIO, ReadWriteTriangleMeshNPZ) {
+ auto cube_mesh = t::geometry::TriangleMesh::CreateBox();
+
+ const std::string filename =
+ utility::filesystem::GetTempDirectoryPath() + "/cube.npz";
+ EXPECT_TRUE(t::io::WriteTriangleMesh(filename, cube_mesh));
+ t::geometry::TriangleMesh mesh;
+ EXPECT_TRUE(t::io::ReadTriangleMesh(filename, mesh));
+ EXPECT_TRUE(
+ mesh.GetVertexPositions().AllClose(cube_mesh.GetVertexPositions()));
+ EXPECT_TRUE(
+ mesh.GetTriangleIndices().AllClose(cube_mesh.GetTriangleIndices()));
+}
+
 // TODO: Add tests for triangle_uvs, materials, triangle_material_ids and
 // textures once these are supported.
 TEST(TriangleMeshIO, TriangleMeshLegecyCompatibility) {