Output normals with a consistent orientation for convex meshes (#48)

Co-authored-by: Seth Parker <csparker247@gmail.com>

apps/src/GeneratePPM.cpp

@@ -5,14 +5,17 @@
 #include "vc/core/io/MeshIO.hpp"
 #include "vc/core/types/PerPixelMap.hpp"
 #include "vc/core/util/Logging.hpp"
+#include "vc/meshing/OrientNormals.hpp"
 #include "vc/texturing/AngleBasedFlattening.hpp"
 #include "vc/texturing/PPMGenerator.hpp"
 
 namespace vc = volcart;
+namespace vcm = volcart::meshing;
+namespace vct = volcart::texturing;
 namespace fs = volcart::filesystem;
 namespace po = boost::program_options;
 
-int main(int argc, char* argv[])
+auto main(int argc, char* argv[]) -> int
 {
     // clang-format off
     po::options_description all("Usage");
@@ -23,7 +26,8 @@ int main(int argc, char* argv[])
         ("output-ppm,o", po::value<std::string>()->required(),
             "Path for the output ppm")
         ("uv-reuse", "If input-mesh is specified, attempt to use its existing "
-            "UV map instead of generating a new one.");
+            "UV map instead of generating a new one.")
+        ("orient-normals", "Auto-orient surface normals towards the mesh centroid");
     // clang-format on
 
     // parsed will hold the values of all parsed options as a Map
@@ -54,11 +58,19 @@ int main(int argc, char* argv[])
     auto mesh = meshFile.mesh;
     auto uvMap = meshFile.uv;
 
+    // Reorient the surface normals
+    if (parsed.count("orient-normals") > 0) {
+        vcm::OrientNormals orient;
+        orient.setReferenceMode(vcm::OrientNormals::ReferenceMode::Centroid);
+        orient.setMesh(mesh);
+        mesh = orient.compute();
+    }
+
     // Generate UV map
     auto genUV = parsed.count("uv-reuse") == 0;
     if (genUV or not uvMap) {
         // ABF
-        vc::texturing::AngleBasedFlattening abf;
+        vct::AngleBasedFlattening abf;
         abf.setMesh(mesh);
         abf.compute();
 
@@ -71,7 +83,7 @@ int main(int argc, char* argv[])
 
     // PPM
     vc::Logger()->info("Generating per-pixel map");
-    vc::texturing::PPMGenerator p;
+    vct::PPMGenerator p;
     p.setDimensions(height, width);
     p.setMesh(mesh);
     p.setUVMap(uvMap);

apps/src/Mesher.cpp

@@ -6,20 +6,21 @@
 #include "vc/core/filesystem.hpp"
 #include "vc/core/io/MeshIO.hpp"
 #include "vc/core/io/PointSetIO.hpp"
-#include "vc/core/types/OrderedPointSet.hpp"
 #include "vc/core/util/Logging.hpp"
 #include "vc/meshing/OrderedPointSetMesher.hpp"
+#include "vc/meshing/OrientNormals.hpp"
 
 namespace fs = volcart::filesystem;
 namespace po = boost::program_options;
 namespace vc = volcart;
+namespace vcm = volcart::meshing;
 
 using psio = vc::PointSetIO<cv::Vec3d>;
 
 auto main(int argc, char* argv[]) -> int
 {
     ///// Parse the command line options /////
-    // All command line options
+    // clang-format off
     po::options_description all("Usage");
     all.add_options()
         ("help,h", "Show this message")
@@ -29,7 +30,9 @@ auto main(int argc, char* argv[]) -> int
             "Path for the output mesh")
         ("mode,m", po::value<int>()->default_value(1),
             "Reading mode: 0 = ASCII, 1 = Binary")
-        ("disable-triangulation", "Disable vertex triangulation");
+        ("disable-triangulation", "Disable vertex triangulation")
+        ("orient-normals", "Auto-orient surface normals towards the mesh centroid");
+    // clang-format on
 
     // parsed will hold the values of all parsed options as a Map
     po::variables_map parsed;
@@ -59,10 +62,18 @@ auto main(int argc, char* argv[]) -> int
 
     // Convert to a mesh
     vc::Logger()->info("Generating mesh...");
-    vc::meshing::OrderedPointSetMesher mesher(inputCloud);
+    vcm::OrderedPointSetMesher mesher(inputCloud);
     mesher.setComputeTriangulation(parsed.count("disable-triangulation") == 0);
     auto output = mesher.compute();
 
+    // Reorient the surface normals
+    if (parsed.count("orient-normals") > 0) {
+        vcm::OrientNormals orient;
+        orient.setReferenceMode(vcm::OrientNormals::ReferenceMode::Centroid);
+        orient.setMesh(output);
+        output = orient.compute();
+    }
+
     // Write the mesh
     vc::Logger()->info("Writing mesh...");
     vc::WriteMesh(outputPath, output);

apps/src/Render.cpp

@@ -103,7 +103,8 @@ static auto GetMeshingOpts() -> po::options_description
             "  3 = Both before and after mesh resampling")
         ("intermediate-mesh", po::value<std::string>(),"Output file path for the "
             "intermediate (i.e. scale + resampled) mesh. File is saved prior "
-            "to flattening. Useful for testing meshing parameters.");
+            "to flattening. Useful for testing meshing parameters.")
+        ("orient-normals", "Auto-orient surface normals towards the mesh centroid");
     // clang-format on
 
     return opts;
@@ -331,7 +332,7 @@ auto main(int argc, char* argv[]) -> int
     };
     // clang-format on
     graph->setProjectMetadata(projectInfo);
-    // Setup a map to keep a reference to important output ports
+    // Set up a map to keep a reference to important output ports
     std::unordered_map<std::string, smgl::Output*> results;
 
     //// Load the segmentation/mesh ////
@@ -479,14 +480,22 @@ auto main(int argc, char* argv[]) -> int
             smooth->input = *results["mesh"];
             results["mesh"] = &smooth->output;
         }
+    }
 
-        // Save the intermediate mesh
-        if (parsed.count("intermediate-mesh") > 0) {
-            fs::path meshPath = parsed["intermediate-mesh"].as<std::string>();
-            auto writer = graph->insertNode<WriteMeshNode>();
-            writer->path = meshPath;
-            writer->mesh = *results["mesh"];
-        }
+    ///// Reorient the mesh normals /////
+    if (parsed.count("orient-normals") > 0) {
+        auto orient = graph->insertNode<OrientNormalsNode>();
+        orient->input = *results["mesh"];
+        orient->referenceMode = OrientNormalsNode::ReferenceMode::Centroid;
+        results["mesh"] = &orient->output;
+    }
+
+    ///// Save the intermediate mesh /////
+    if (parsed.count("intermediate-mesh") > 0) {
+        fs::path meshPath = parsed["intermediate-mesh"].as<std::string>();
+        auto writer = graph->insertNode<WriteMeshNode>();
+        writer->path = meshPath;
+        writer->mesh = *results["mesh"];
     }
 
     ///// Flattening /////

core/include/vc/core/shapes/Cube.hpp

@@ -41,18 +41,17 @@ class Cube : public ShapePrimitive
 
         // generate the 12 cells for faces
         addCell_(0, 1, 2);
-        addCell_(0, 1, 5);
         addCell_(0, 2, 3);
-        addCell_(0, 3, 4);
-        addCell_(0, 4, 5);
-        addCell_(1, 2, 6);
-        addCell_(1, 5, 6);
-        addCell_(2, 3, 7);
-        addCell_(2, 6, 7);
-        addCell_(3, 4, 7);
-        addCell_(4, 5, 7);
-        addCell_(5, 6, 7);
-
+        addCell_(3, 2, 6);
+        addCell_(3, 6, 7);
+        addCell_(7, 6, 5);
+        addCell_(7, 5, 4);
+        addCell_(4, 5, 1);
+        addCell_(4, 1, 0);
+        addCell_(0, 3, 7);
+        addCell_(0, 7, 4);
+        addCell_(5, 6, 2);
+        addCell_(5, 2, 1);
     }  // Constructor
 
 };  // Cube

core/include/vc/core/types/Metadata.hpp

@@ -9,6 +9,7 @@
 #include <opencv2/core.hpp>
 
 #include "vc/core/filesystem.hpp"
+#include "vc/core/util/Json.hpp"
 
 namespace volcart
 {
@@ -104,26 +105,3 @@ class Metadata
     volcart::filesystem::path path_;
 };
 }  // namespace volcart
-
-/** JSON Serializer for cv::Vec */
-namespace nlohmann
-{
-template <typename T, int Cn>
-struct adl_serializer<cv::Vec<T, Cn>> {
-    // NOLINTNEXTLINE(readability-identifier-naming): Must be exact signature
-    static void to_json(nlohmann::json& j, const cv::Vec<T, Cn>& v)
-    {
-        for (int i = 0; i < Cn; i++) {
-            j.push_back(v[i]);
-        }
-    }
-
-    // NOLINTNEXTLINE(readability-identifier-naming): Must be exact signature
-    static void from_json(const nlohmann::json& j, cv::Vec<T, Cn>& v)
-    {
-        for (int i = 0; i < Cn; i++) {
-            v[i] = j.at(i).get<T>();
-        }
-    }
-};
-}  // namespace nlohmann