Added beginning of new osgUtil::Simplifier

src/osgUtil/Simplifier.cpp

@@ -0,0 +1,161 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2003 Robert Osfield 
+ *
+ * This library is open source and may be redistributed and/or modified under  
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or 
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
+ * OpenSceneGraph Public License for more details.
+*/
+
+#include <osg/TriangleIndexFunctor>
+
+#include <osgUtil/Simplifier>
+
+#include <set>
+#include <iostream>
+
+using namespace osgUtil;
+
+
+class EdgeCollapse
+{
+public:
+
+    EdgeCollapse():
+        _targetNumTriangles(0) {}
+    ~EdgeCollapse() {}
+
+    void setGeometry(osg::Geometry* geometry);
+    osg::Geometry* getGeometry() { return _geometry; }
+
+    void setTargetNumOfTriangles(unsigned int num) { _targetNumTriangles = num; }
+
+    unsigned int getNumOfTriangles() { return 0; }
+
+    bool collapseMinimumErrorEdge() { return false; }
+
+    void copyBackToGeometry() {}
+
+    class Triangle;
+    class Edge;
+
+
+    struct Point : public osg::Referenced
+    {
+        Point() {}
+        
+        unsigned int _index;
+    };
+
+    struct Edge : public osg::Referenced
+    {
+        Edge() {}
+        
+        osg::ref_ptr<Point> _p1;
+        osg::ref_ptr<Point> _p2;
+        
+        osg::ref_ptr<Triangle> _t1;
+        osg::ref_ptr<Triangle> _t2;
+        
+        void setErrorMetric(float errorMetric) { _errorMetric = errorMetric; }
+        float getErrorMetric() const { return _errorMetric; }
+        
+        float _errorMetric;
+    };
+
+    struct Triangle : public osg::Referenced
+    {
+        Triangle() {}
+        
+        osg::ref_ptr<Point> _p1;
+        osg::ref_ptr<Point> _p2;
+        osg::ref_ptr<Point> _p3;
+        
+        osg::ref_ptr<Edge> _e1;
+        osg::ref_ptr<Edge> _e2;
+        osg::ref_ptr<Edge> _e3;
+    };
+
+
+    struct LessPtr
+    {
+        inline bool operator() (const osg::ref_ptr<Edge>& lhs,const osg::ref_ptr<Edge>& rhs) const
+        {
+            return lhs->getErrorMetric()<rhs->getErrorMetric();
+        }
+    };
+
+    typedef std::set<osg::ref_ptr<Edge>,LessPtr> EdgeSet;
+
+
+    void addTriangle(unsigned int p1, unsigned int p2, unsigned int p3)
+    {
+        std::cout<<"addTriangle("<<p1<<","<<p2<<","<<p3<<")"<<std::endl;
+    }
+
+protected:
+
+    osg::Geometry*                  _geometry;
+    unsigned int                    _targetNumTriangles;
+    EdgeSet                         _edgeSet;
+    
+};
+
+struct MyTriangleOperator
+{
+
+    MyTriangleOperator():_ec(0) {}
+
+    void setEdgeCollapse(EdgeCollapse* ec) { _ec = ec; }
+    
+    EdgeCollapse* _ec;    
+
+    // for use  in the triangle functor.
+    inline void operator()(unsigned int p1, unsigned int p2, unsigned int p3)
+    {
+        _ec->addTriangle(p1,p2,p3);
+    }
+
+};
+
+typedef osg::TriangleIndexFunctor<MyTriangleOperator> MyTriangleIndexFunctor;
+
+void EdgeCollapse::setGeometry(osg::Geometry* geometry)
+{
+    _geometry = geometry;
+
+    MyTriangleIndexFunctor collectTriangles;
+    collectTriangles.setEdgeCollapse(this);
+}
+ 
+Simplifier::Simplifier()
+{
+}
+
+void Simplifier::simplify(osg::Geometry& geometry, float sampleRatio)
+{
+    EdgeCollapse ec;
+    ec.setGeometry(&geometry);
+
+    ec.setTargetNumOfTriangles((unsigned int)(sampleRatio*(float)ec.getNumOfTriangles()));
+
+    while (ec.collapseMinimumErrorEdge()) {}
+
+    ec.copyBackToGeometry();
+}
+
+void Simplifier::simplify(osg::Geometry& geometry, unsigned int targetNumberOfTriangles)
+{
+    EdgeCollapse ec;
+    ec.setGeometry(&geometry);
+
+    ec.setTargetNumOfTriangles(targetNumberOfTriangles);
+
+    while (ec.collapseMinimumErrorEdge()) {}
+
+    ec.copyBackToGeometry();
+}