Add local average base normals

The base normal of each node will be averaged by sum of all the neighbors' base normal.

thirdparty/nodemesh/nodemesh/builder.cpp

@@ -304,6 +304,7 @@ bool Builder::build()
     }
     
     unifyBaseNormals();
+    localAverageBaseNormals();
     
     for (const auto &nodeIndex: m_sortedNodeIndices) {
         if (!generateCutsForNode(nodeIndex))
@@ -318,6 +319,25 @@ bool Builder::build()
     return succeed;
 }
 
+void Builder::localAverageBaseNormals()
+{
+    std::vector<QVector3D> localAverageNormals;
+    for (size_t nodeIndex = 0; nodeIndex < m_nodes.size(); ++nodeIndex) {
+        const auto &node = m_nodes[nodeIndex];
+        QVector3D sumOfNormals = node.baseNormal;
+        for (const auto &edgeIndex: node.edges) {
+            const auto &edge = m_edges[edgeIndex];
+            size_t neighborIndex = edge.neiborOf(nodeIndex);
+            const auto &neighbor = m_nodes[neighborIndex];
+            sumOfNormals += neighbor.baseNormal;
+        }
+        localAverageNormals.push_back(sumOfNormals.normalized());
+    }
+    for (size_t nodeIndex = 0; nodeIndex < m_nodes.size(); ++nodeIndex) {
+        m_nodes[nodeIndex].baseNormal = localAverageNormals[nodeIndex];
+    }
+}
+
 bool Builder::validateNormal(const QVector3D &normal)
 {
     if (normal.isNull()) {

thirdparty/nodemesh/nodemesh/builder.h

@@ -83,7 +83,7 @@ private:
         std::vector<size_t> nodes;
         std::vector<std::pair<std::vector<size_t>, QVector3D>> cuts;
         
-        size_t neiborOf(size_t nodeIndex)
+        size_t neiborOf(size_t nodeIndex) const
         {
             const auto &otherIndex = nodes[0];
             if (otherIndex == nodeIndex)
@@ -131,6 +131,7 @@ private:
     QVector3D revisedBaseNormalAcordingToCutNormal(const QVector3D &baseNormal, const QVector3D &cutNormal);
     void resolveInitialTraverseDirectionRecursively(size_t nodeIndex, const QVector3D *from, std::set<size_t> *visited);
     void unifyBaseNormals();
+    void localAverageBaseNormals();
     void resolveTraverseDirection(size_t nodeIndex);
     bool generateCutsForNode(size_t nodeIndex);
     bool tryWrapMultipleBranchesForNode(size_t nodeIndex, std::vector<float> &offsets, bool &offsetsChanged);