From 3e8f2ab4402fcc78e6a7284288b48bbc51b6cc40 Mon Sep 17 00:00:00 2001
From: Philippose Rajan <philippose>
Date: Wed, 15 Sep 2010 20:52:20 +0000
Subject: [PATCH] * Added support for extracting 8 node Quad elements *
 Modified the Ng_GetElement_2D function to return also the element type giving
 it the same base functionality as Ng_GetSurfaceElement, but with the
 capability of returning the region index too (called matnum)

---
 nglib/nglib.cpp | 38 +++++++++++++++++++++++++++++++++++---
 nglib/nglib.h   |  9 +++++----
 2 files changed, 40 insertions(+), 7 deletions(-)

diff --git a/nglib/nglib.cpp b/nglib/nglib.cpp
index 0c9cffef..cecdb299 100644
--- a/nglib/nglib.cpp
+++ b/nglib/nglib.cpp
@@ -228,7 +228,16 @@ namespace nglib
       {
       case 3: et = NG_TRIG; break;
       case 4: et = NG_QUAD; break;
-      case 6: et = NG_TRIG6; break;
+      case 6: 
+         switch (el.GetNV())
+         {
+         case 3: et = NG_TRIG6; break;
+         case 4: et = NG_QUAD6; break;
+         default:
+            et = NG_TRIG6; break;
+         }
+         break;
+      case 8: et = NG_QUAD8; break;
       default:
          et = NG_TRIG; break; // for the compiler
       }
@@ -377,13 +386,36 @@ namespace nglib
 
 
 
-   DLL_HEADER void Ng_GetElement_2D (Ng_Mesh * mesh, int num, int * pi, int * matnum)
+   DLL_HEADER Ng_Surface_Element_Type
+      Ng_GetElement_2D (Ng_Mesh * mesh, int num, int * pi, int * matnum)
    {
       const Element2d & el = ((Mesh*)mesh)->SurfaceElement(num);
-      for (int i = 1; i <= 3; i++)
+      for (int i = 1; i <= el.GetNP(); i++)
          pi[i-1] = el.PNum(i);
+
+      Ng_Surface_Element_Type et;
+      switch (el.GetNP())
+      {
+      case 3: et = NG_TRIG; break;
+      case 4: et = NG_QUAD; break;
+      case 6: 
+         switch (el.GetNV())
+         {
+         case 3: et = NG_TRIG6; break;
+         case 4: et = NG_QUAD6; break;
+         default:
+            et = NG_TRIG6; break;
+         }
+         break;
+      case 8: et = NG_QUAD8; break;
+      default:
+         et = NG_TRIG; break; // for the compiler
+      }
+
       if (matnum)
          *matnum = el.GetIndex();
+
+      return et;
    }
 
 
diff --git a/nglib/nglib.h b/nglib/nglib.h
index d571a868..5bb75e67 100644
--- a/nglib/nglib.h
+++ b/nglib/nglib.h
@@ -40,7 +40,7 @@
 #define NG_VOLUME_ELEMENT_MAXPOINTS 10
 
 /// Maximum allowed number of nodes per surface element
-#define NG_SURFACE_ELEMENT_MAXPOINTS 6
+#define NG_SURFACE_ELEMENT_MAXPOINTS 8
 
 
 
@@ -67,7 +67,7 @@ typedef void * Ng_OCC_TopTools_IndexedMapOfShape;
 // *** Special Enum types used within Netgen ***********
 /// Currently implemented surface element types
 enum Ng_Surface_Element_Type 
-   { NG_TRIG = 1, NG_QUAD = 2, NG_TRIG6 = 3 };
+   { NG_TRIG = 1, NG_QUAD = 2, NG_TRIG6 = 3, NG_QUAD6 = 4, NG_QUAD8 = 5 };
 
 /// Currently implemented volume element types
 enum Ng_Volume_Element_Type 
@@ -532,8 +532,9 @@ DLL_HEADER int Ng_GetNSeg_2D (Ng_Mesh * mesh);
 //  return point coordinates
 DLL_HEADER void Ng_GetPoint_2D (Ng_Mesh * mesh, int num, double * x);
 
-// return 2d triangles
-DLL_HEADER void Ng_GetElement_2D (Ng_Mesh * mesh, int num, int * pi, int * matnum = NULL);
+// return 2d elements
+DLL_HEADER Ng_Surface_Element_Type 
+Ng_GetElement_2D (Ng_Mesh * mesh, int num, int * pi, int * matnum = NULL);
 
 // return 2d boundary segment
 DLL_HEADER void Ng_GetSegment_2D (Ng_Mesh * mesh, int num, int * pi, int * matnum = NULL);