BUG: Changes the Face Label value to -1 for boundary triangles in SurfaceNets

Also updated documentation with a short section about the face labels.

Signed-off-by: Michael Jackson <[email protected]>

Author: imikejackson

src/Plugins/SimplnxCore/docs/QuickSurfaceMeshFilter.md

@@ -63,13 +63,20 @@ One of the arrays to come out of the algorithm is the "Node Type" vertex array.
 | 13 | Node that is on the exterior of the mesh and is a triple line  |
 | 14 | Node that is on the exterior of the mesh and is a quadruple point   |
 
+### Exterior or Boundary Triangles
+
+Each triangle that is created will have an 2 component attribute called `Face Labels` that represent the Feature ID on either
+side of the triangle. If one of the triangles represents the border of the virtual box then one of the FaceLables will
+have a value of -1.
+
 ## Notes
 
-The Quickmesh algorithm is very crude and naive in its implementation. This filter 
+The Quick Mesh algorithm is very crude and naive in its implementation. This filter
 along with the Laplacian Smoothing filter can give you reasonable results. The
-newer filter that should replace both the quick mesh and the Laplacian Smoothing
-filter is the "SurfaceNets" surface meshing algorithm. This will create the surface
-mesh and smooth in a single filter and give subjectively better results.
+newer filter that should replace both the Quick Mesh and the Laplacian Smoothing
+filter is the "Surface Nets" surface meshing algorithm. This will create the surface
+mesh and smooth in a single filter and give subjectively better results and perform
+much faster at both.
 
 % Auto generated parameter table will be inserted here
 

src/Plugins/SimplnxCore/docs/SurfaceNetsFilter.md

@@ -58,6 +58,12 @@ Nodes that appear on the exterior of a volume have Node Type values starting at
 
 ![Exterior Node Types](Images/SurfaceNets_NodeType_Exterior.png)
 
+### Exterior or Boundary Triangles
+
+Each triangle that is created will have an 2 component attribute called `Face Labels` that represent the Feature ID on either
+side of the triangle. If one of the triangles represents the border of the virtual box then one of the FaceLables will
+have a value of -1.
+
 ## Notes
 
 This filter should be used in place of the "QuickMesh Surface Filter".

src/Plugins/SimplnxCore/src/SimplnxCore/Filters/Algorithms/SurfaceNets.cpp

@@ -242,7 +242,6 @@ Result<> SurfaceNets::operator()()
   std::array<VertexData, 4> vData{};
   for(int idxVtx = 0; idxVtx < nodeCount; idxVtx++)
   {
-
     // Back-bottom edge
     if(cellMapPtr->getEdgeQuad(idxVtx, MMCellFlag::Edge::BackBottomEdge, vertexIndices.data(), quadLabels.data()))
     {
@@ -420,5 +419,14 @@ Result<> SurfaceNets::operator()()
     }
   }
 
+  // Now run through the FaceLabels to make them consistent with Quick Surface Mesh
+  for(usize tIdx = 0; tIdx < triangleCount * 2; tIdx++)
+  {
+    if(faceLabels[tIdx] == 0)
+    {
+      faceLabels[tIdx] = -1;
+    }
+  }
+
   return {};
 }