From 86a05d1bfb281a9aa36888e11725ff7f021c0554 Mon Sep 17 00:00:00 2001
From: Jeremy HU <huxingyi@msn.com>
Date: Sun, 16 Oct 2022 19:56:10 +1100
Subject: [PATCH] Fix node forward direction

---
 dust3d/mesh/tube_mesh_builder.cc | 12 +++++++++---
 dust3d/mesh/tube_mesh_builder.h  |  1 +
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/dust3d/mesh/tube_mesh_builder.cc b/dust3d/mesh/tube_mesh_builder.cc
index f49ebdb4..f9ae4efa 100644
--- a/dust3d/mesh/tube_mesh_builder.cc
+++ b/dust3d/mesh/tube_mesh_builder.cc
@@ -62,12 +62,15 @@ void TubeMeshBuilder::buildNodePositionAndDirections()
 
     std::vector<Vector3> rawDirections;
     rawDirections.resize(m_nodePositions.size());
+    m_nodeForwardDistances.resize(m_nodePositions.size());
     m_nodeForwardDirections.resize(m_nodePositions.size());
     if (m_nodePositions.size() >= 2) {
         if (m_isCircle) {
             for (size_t i = 0; i < m_nodePositions.size(); ++i) {
                 size_t j = (i + 1) % m_nodePositions.size();
-                rawDirections[i] = (m_nodePositions[j] - m_nodePositions[i]).normalized();
+                rawDirections[i] = (m_nodePositions[j] - m_nodePositions[i]);
+                m_nodeForwardDistances[i] = rawDirections[i].length();
+                rawDirections[i].normalize();
             }
             for (size_t i = 0; i < m_nodePositions.size(); ++i) {
                 size_t j = (i + 1) % m_nodePositions.size();
@@ -76,13 +79,16 @@ void TubeMeshBuilder::buildNodePositionAndDirections()
         } else {
             for (size_t j = 1; j < m_nodePositions.size(); ++j) {
                 size_t i = j - 1;
-                rawDirections[i] = (m_nodePositions[j] - m_nodePositions[i]).normalized();
+                rawDirections[i] = (m_nodePositions[j] - m_nodePositions[i]);
+                m_nodeForwardDistances[i] = rawDirections[i].length();
+                rawDirections[i].normalize();
             }
             rawDirections[m_nodeForwardDirections.size() - 1] = rawDirections[m_nodeForwardDirections.size() - 2];
             m_nodeForwardDirections.front() = rawDirections.front();
             for (size_t j = 1; j + 1 < m_nodePositions.size(); ++j) {
                 size_t i = j - 1;
-                m_nodeForwardDirections[j] = (rawDirections[i] + rawDirections[j]).normalized();
+                m_nodeForwardDirections[j] = (rawDirections[i] * m_nodeForwardDistances[j] + 
+                    rawDirections[j] * m_nodeForwardDistances[i]).normalized();
             }
             m_nodeForwardDirections.back() = rawDirections.back();
         }
diff --git a/dust3d/mesh/tube_mesh_builder.h b/dust3d/mesh/tube_mesh_builder.h
index c5dc61ff..fd0ec653 100644
--- a/dust3d/mesh/tube_mesh_builder.h
+++ b/dust3d/mesh/tube_mesh_builder.h
@@ -53,6 +53,7 @@ private:
     std::vector<MeshNode> m_nodes;
     std::vector<Vector3> m_nodePositions;
     std::vector<Vector3> m_nodeForwardDirections;
+    std::vector<double> m_nodeForwardDistances;
     std::vector<Vector3> m_generatedVertices;
     std::vector<std::vector<size_t>> m_generatedFaces;
     Vector3 m_generatedBaseNormal;