From bd6da5699ee63a0d568c940328cdb82cbfaac94a Mon Sep 17 00:00:00 2001
From: wmayer <wmayer@users.sourceforge.net>
Date: Tue, 24 Sep 2019 17:19:15 +0200
Subject: [PATCH] extend texture mapping to meshes

---
 src/Mod/Mesh/App/MeshTexture.cpp | 71 ++++++++++++++++++++++++++++++++
 src/Mod/Mesh/App/MeshTexture.h   | 15 +++++--
 2 files changed, 82 insertions(+), 4 deletions(-)

diff --git a/src/Mod/Mesh/App/MeshTexture.cpp b/src/Mod/Mesh/App/MeshTexture.cpp
index 0018ef1a95..7f1b346991 100644
--- a/src/Mod/Mesh/App/MeshTexture.cpp
+++ b/src/Mod/Mesh/App/MeshTexture.cpp
@@ -46,6 +46,77 @@ MeshTexture::MeshTexture(const Mesh::MeshObject& mesh, const MeshCore::Material
     }
 }
 
+void MeshTexture::apply(const Mesh::MeshObject& mesh, const App::Color& defaultColor, MeshCore::Material &material)
+{
+    // copy the color values because the passed material could be the same instance as 'materialRefMesh'
+    std::vector<App::Color> textureColor = materialRefMesh.diffuseColor;
+    material.diffuseColor.clear();
+    material.binding = MeshCore::MeshIO::OVERALL;
+
+    if (kdTree.get()) {
+        // the points of the current mesh
+        std::vector<App::Color> diffuseColor;
+        const MeshCore::MeshPointArray& points = mesh.getKernel().GetPoints();
+        const MeshCore::MeshFacetArray& facets = mesh.getKernel().GetFacets();
+
+        if (binding == MeshCore::MeshIO::PER_VERTEX) {
+            diffuseColor.reserve(points.size());
+            for (size_t index=0; index<points.size(); index++) {
+                unsigned long pos = kdTree->FindExact(points[index]);
+                if (pos < countPointsRefMesh) {
+                    diffuseColor.push_back(textureColor[pos]);
+                }
+                else {
+                    diffuseColor.push_back(defaultColor);
+                }
+            }
+
+            if (diffuseColor.size() == points.size()) {
+                material.diffuseColor.swap(diffuseColor);
+                material.binding = MeshCore::MeshIO::PER_VERTEX;
+            }
+        }
+        else if (binding == MeshCore::MeshIO::PER_FACE) {
+            // the values of the map give the point indices of the original mesh
+            std::vector<unsigned long> pointMap;
+            pointMap.reserve(points.size());
+            for (size_t index=0; index<points.size(); index++) {
+                unsigned long pos = kdTree->FindExact(points[index]);
+                if (pos < countPointsRefMesh) {
+                    pointMap.push_back(pos);
+                }
+                else {
+                    pointMap.push_back(ULONG_MAX);
+                }
+            }
+
+            // now determine the facet indices of the original mesh
+            if (pointMap.size() == points.size()) {
+                diffuseColor.reserve(facets.size());
+                for (auto it : facets) {
+                    unsigned long index1 = pointMap[it._aulPoints[0]];
+                    unsigned long index2 = pointMap[it._aulPoints[1]];
+                    unsigned long index3 = pointMap[it._aulPoints[2]];
+                    if (index1 != ULONG_MAX && index2 != ULONG_MAX && index3 != ULONG_MAX) {
+                        std::vector<unsigned long> found = refPnt2Fac->GetIndices(index1, index2, index3);
+                        if (found.size() == 1) {
+                            diffuseColor.push_back(textureColor[found.front()]);
+                        }
+                    }
+                    else {
+                        diffuseColor.push_back(defaultColor);
+                    }
+                }
+            }
+
+            if (diffuseColor.size() == facets.size()) {
+                material.diffuseColor.swap(diffuseColor);
+                material.binding = MeshCore::MeshIO::PER_FACE;
+            }
+        }
+    }
+}
+
 void MeshTexture::apply(const Mesh::MeshObject& mesh, MeshCore::Material &material)
 {
     // copy the color values because the passed material could be the same instance as 'materialRefMesh'
diff --git a/src/Mod/Mesh/App/MeshTexture.h b/src/Mod/Mesh/App/MeshTexture.h
index c0eff198da..45c9bd740a 100644
--- a/src/Mod/Mesh/App/MeshTexture.h
+++ b/src/Mod/Mesh/App/MeshTexture.h
@@ -36,8 +36,8 @@ namespace Mesh
 
 /*! The MeshTexture class.
   This algorithm is useful to update the material after a mesh has been modified
-  by removing points or facets. It can't be used if the coordinates of points have
-  changed or if new points have been added.
+  by removing points or facets. If the coordinates of points have changed or if
+  new points have been added then a pre-defined color will be set.
   @author Werner Mayer
  */
 class MeshExport MeshTexture
@@ -48,8 +48,15 @@ public:
      */
     MeshTexture(const Mesh::MeshObject& mesh, const MeshCore::Material &material);
     /*!
-      The \a mesh must be a sub-set of the mesh passed to the constructor. This means
-      that points or facets can be removed but neither changed nor new points added.
+     Find common points or facets of this to the original mesh. For points or facets
+     that don't match \a defaultColor will be used instead, otherwise the color of the
+     original material is used.
+     */
+    void apply(const Mesh::MeshObject& mesh, const App::Color& defaultColor, MeshCore::Material &material);
+    /*!
+     Find common points or facets of this to the original mesh and use the color of the original material.
+     If for a point of \a mesh no matching point of the original mesh can be found the texture mapping will
+     fail.
      */
     void apply(const Mesh::MeshObject& mesh, MeshCore::Material &material);