From 70470bc84a518a70a6447f0d9fb2f0de379571ad Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Mon, 28 Aug 2006 19:01:03 +0000
Subject: [PATCH] From Roger James, "I have been going through my modified osg
 files and came across this fix to the Tesselator. From memory it handles a
 problem with per primitive normal binding. I must have forgotten to submit
 it."

---
 include/osgUtil/Tesselator |  5 ++++-
 src/osgUtil/Tesselator.cpp | 28 ++++++++++++++++++++++------
 2 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/include/osgUtil/Tesselator b/include/osgUtil/Tesselator
index 9c72bc2b9..d766d3317 100644
--- a/include/osgUtil/Tesselator
+++ b/include/osgUtil/Tesselator
@@ -120,7 +120,7 @@ class OSGUTIL_EXPORT Tesselator : public osg::Referenced
          * these will leak memory if not removed when retesselating. */
         void reduceArray(osg::Array * cold, const unsigned int nnu);
 
-        void collectTesselation(osg::Geometry &cxgeom);
+        void collectTesselation(osg::Geometry &cxgeom, unsigned int originalIndex);
         
         typedef std::map<osg::Vec3*,unsigned int> VertexPtrToIndexMap;
         void addContour(GLenum  mode, unsigned int first, unsigned int last, osg::Vec3Array* vertices);
@@ -236,6 +236,9 @@ class OSGUTIL_EXPORT Tesselator : public osg::Referenced
 
         /** the gluTessNormal for tesselation hint */
         osg::Vec3 tessNormal;
+
+        /** count of number of extra primitives added */
+        unsigned int _extraPrimitives;
 };
 
 }
diff --git a/src/osgUtil/Tesselator.cpp b/src/osgUtil/Tesselator.cpp
index 87b3ee7c4..06e29750f 100644
--- a/src/osgUtil/Tesselator.cpp
+++ b/src/osgUtil/Tesselator.cpp
@@ -177,6 +177,7 @@ void Tesselator::retesselatePolygons(osg::Geometry &geom)
     // the reset is needed by the flt loader which reuses a tesselator for triangulating polygons.
     // as such it might be reset by other loaders/developers in future.
     _index=0; // reset the counter for indexed vertices
+    _extraPrimitives = 0;
     if (!_numberVerts) {
         _numberVerts=geom.getVertexArray()->getNumElements();
         // save the contours for complex (winding rule) tesselations
@@ -206,6 +207,7 @@ void Tesselator::retesselatePolygons(osg::Geometry &geom)
     }
     // process all the contours into the tesselator
     int noContours = _Contours.size();
+    int currentPrimitive = 0;
     for(int primNo=0;primNo<noContours;++primNo)
     {
         osg::ref_ptr<osg::PrimitiveSet> primitive = _Contours[primNo].get();
@@ -227,7 +229,8 @@ void Tesselator::retesselatePolygons(osg::Geometry &geom)
                             addContour(primitive->getMode(),first,last,vertices);
                             first = last;
                         endTesselation();
-                        collectTesselation(geom);
+                        collectTesselation(geom, currentPrimitive);
+                        currentPrimitive++;
                     }
                 }
                 else
@@ -236,7 +239,8 @@ void Tesselator::retesselatePolygons(osg::Geometry &geom)
                         beginTesselation();
                         addContour(primitive.get(), vertices);
                         endTesselation();
-                        collectTesselation(geom);
+                        collectTesselation(geom, currentPrimitive);
+                        currentPrimitive++;
                     } else { // April 2005 gwm triangles don't need to be retesselated
                         geom.addPrimitiveSet(primitive.get());
                     }
@@ -266,7 +270,7 @@ void Tesselator::retesselatePolygons(osg::Geometry &geom)
     if (_ttype==TESS_TYPE_GEOMETRY) {
         endTesselation();
     
-        collectTesselation(geom);    
+        collectTesselation(geom, 0);    
     }
 }
 
@@ -646,7 +650,7 @@ unsigned int _computeNumberOfPrimitives(const osg::Geometry& geom)
     return totalNumberOfPrimitives;
 }
 //
-void Tesselator::collectTesselation(osg::Geometry &geom)
+void Tesselator::collectTesselation(osg::Geometry &geom, unsigned int originalIndex)
 {
     osg::Vec3Array* vertices = dynamic_cast<osg::Vec3Array*>(geom.getVertexArray());
     VertexPtrToIndexMap vertexPtrToIndexMap;
@@ -713,7 +717,10 @@ void Tesselator::collectTesselation(osg::Geometry &geom)
               if (primItr==_primList.begin()) 
               {   // first primitive so collect primitive normal & colour.
                   if (normals) {
-                      norm=(*normals)[iprim]; // GWM Sep 2002 the flat shaded normal
+                     if (geom.getNormalBinding()==osg::Geometry::BIND_PER_PRIMITIVE)
+                        norm=(*normals)[originalIndex + _extraPrimitives];
+                     else
+                        norm=(*normals)[iprim]; // GWM Sep 2002 the flat shaded normal
                   }
                   if (cols4) {
                       primCol4=(*cols4)[iprim]; // GWM Dec 2003 the flat shaded rgba colour
@@ -730,7 +737,16 @@ void Tesselator::collectTesselation(osg::Geometry &geom)
               }
               else
               { // later primitives use same colour
-                  if (normals) normals->push_back(norm); // GWM Sep 2002 add flat shaded normal for new facet
+                  if (normals)
+                  {
+                      if (geom.getNormalBinding()==osg::Geometry::BIND_PER_PRIMITIVE)
+                      {
+                          _extraPrimitives++;
+                          normals->insert(normals->begin() + originalIndex + _extraPrimitives, norm);
+                      }
+                      else
+                        normals->push_back(norm); // GWM Sep 2002 add flat shaded normal for new facet
+                  }
                   if (cols4 && _index>=cols4->size()) {
                     cols4->push_back(primCol4); // GWM Dec 2003 add flat shaded colour for new facet
                   }