1 files changed, 122 insertions, 0 deletions
diff --git a/thirdparty/thekla_atlas/nvmesh/MeshTopology.cpp b/thirdparty/thekla_atlas/nvmesh/MeshTopology.cpp
new file mode 100644
index 0000000000..e7e1dce421
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/MeshTopology.cpp
@@ -0,0 +1,122 @@
+// This code is in the public domain -- castanyo@yahoo.es
+
+#include "nvmesh.h" // pch
+
+#include "nvcore/Array.h"
+#include "nvcore/BitArray.h"
+
+#include "nvmesh/MeshTopology.h"
+#include "nvmesh/halfedge/Mesh.h"
+#include "nvmesh/halfedge/Edge.h"
+#include "nvmesh/halfedge/Face.h"
+
+using namespace nv;
+
+void MeshTopology::buildTopologyInfo(const HalfEdge::Mesh * mesh)
+{
+    const uint vertexCount = mesh->colocalVertexCount();
+    const uint faceCount = mesh->faceCount();
+    const uint edgeCount = mesh->edgeCount();
+
+    nvDebug( "--- Building mesh topology:\n" );
+
+    Array<uint> stack(faceCount);
+
+    BitArray bitFlags(faceCount);
+    bitFlags.clearAll();
+
+    // Compute connectivity.
+    nvDebug( "---   Computing connectivity.\n" );
+
+    m_connectedCount = 0;
+
+    for(uint f = 0; f < faceCount; f++ ) {
+        if( bitFlags.bitAt(f) == false ) {
+            m_connectedCount++;
+
+            stack.pushBack( f );
+            while( !stack.isEmpty() ) {
+
+                const uint top = stack.back();
+                nvCheck(top != NIL);
+                stack.popBack();
+
+                if( bitFlags.bitAt(top) == false ) {
+                    bitFlags.setBitAt(top);
+
+                    const HalfEdge::Face * face = mesh->faceAt(top);
+                    const HalfEdge::Edge * firstEdge = face->edge;
+                    const HalfEdge::Edge * edge = firstEdge;
+
+                    do {
+                        const HalfEdge::Face * neighborFace = edge->pair->face;
+                        if (neighborFace != NULL) {
+                            stack.pushBack(neighborFace->id);
+                        }
+                        edge = edge->next;
+                    } while(edge != firstEdge);
+                }
+            }
+        }
+    }
+    nvCheck(stack.isEmpty());
+    nvDebug( "---   %d connected components.\n", m_connectedCount );
+
+
+    // Count boundary loops.
+    nvDebug( "---   Counting boundary loops.\n" );
+    m_boundaryCount = 0;
+
+    bitFlags.resize(edgeCount);
+    bitFlags.clearAll();
+
+    // Don't forget to link the boundary otherwise this won't work.
+    for (uint e = 0; e < edgeCount; e++)
+    {
+        const HalfEdge::Edge * startEdge = mesh->edgeAt(e);
+        if (startEdge != NULL && startEdge->isBoundary() && bitFlags.bitAt(e) == false)
+        {
+            nvDebugCheck(startEdge->face != NULL);
+            nvDebugCheck(startEdge->pair->face == NULL);
+
+            startEdge = startEdge->pair;
+
+            m_boundaryCount++;
+
+            const HalfEdge::Edge * edge = startEdge;
+            do {
+                bitFlags.setBitAt(edge->id / 2);
+                edge = edge->next;
+            } while(startEdge != edge);
+        }
+    }
+    nvDebug("---   %d boundary loops found.\n", m_boundaryCount );
+
+
+    // Compute euler number.
+    m_eulerNumber = vertexCount - edgeCount + faceCount;
+    nvDebug("---   Euler number: %d.\n", m_eulerNumber);
+
+
+    // Compute genus. (only valid on closed connected surfaces)
+    m_genus = -1;
+    if( isClosed() && isConnected() ) {
+        m_genus = (2 - m_eulerNumber) / 2;
+        nvDebug("---   Genus: %d.\n", m_genus);
+    }
+}
+
+
+/*static*/ bool MeshTopology::isQuadOnly(const HalfEdge::Mesh * mesh)
+{
+    const uint faceCount = mesh->faceCount();
+    for(uint f = 0; f < faceCount; f++)
+    {
+        const HalfEdge::Face * face = mesh->faceAt(f);
+        if (face->edgeCount() != 4) {
+            return false;
+        }
+    }
+
+    return true;
+}