[ADD] Perform transformation before triangulate the head surface to get a better looking mesh.

src/graphicsEngine/WGEGeometryUtils.cpp

@@ -95,7 +95,7 @@ osg::ref_ptr< osg::Vec3Array > wge::generateCuboidQuadNormals( const std::vector
     return vertices;
 }
 
-WTriangleMesh wge::triangulate( const std::vector< wmath::WPosition >& points )
+WTriangleMesh wge::triangulate( const std::vector< wmath::WPosition >& points, double transformationFactor )
 {
     WTriangleMesh mesh;
     mesh.setVertices( points );
@@ -104,6 +104,25 @@ WTriangleMesh wge::triangulate( const std::vector< wmath::WPosition >& points )
     {
         osg::ref_ptr< osg::Vec3Array > osgPoints = wge::osgVec3Array( points );
 
+        if( transformationFactor != 0.0 )
+        {
+            // Transform the points as described in the Doxygen description of
+            // this function.
+            osg::Vec3 centroid;
+            for( std::size_t pointID = 0; pointID < osgPoints->size(); ++pointID )
+            {
+                centroid += (*osgPoints)[pointID];
+            }
+            centroid /= osgPoints->size();
+
+            for( std::size_t pointID = 0; pointID < osgPoints->size(); ++pointID )
+            {
+                const double factor = ( (*osgPoints)[pointID].z() - centroid.z() ) * transformationFactor + 1.0;
+                (*osgPoints)[pointID].x() = ( (*osgPoints)[pointID].x() - centroid.x() ) * factor + centroid.x();
+                (*osgPoints)[pointID].y() = ( (*osgPoints)[pointID].y() - centroid.y() ) * factor + centroid.y();
+            }
+        }
+
         // The osg triangulator sorts the points and returns the triangles with
         // the indizes of the sorted points. Since we don't want to change the
         // sequence of the points, we have to save the original index of each

src/graphicsEngine/WGEGeometryUtils.h

@@ -105,12 +105,25 @@ namespace wge
     osg::ref_ptr< osg::Vec3Array > generateCuboidQuadNormals( const std::vector< wmath::WPosition >& corners );
 
     /**
-     * Calculate the Delaunay Triangulatation of the given points.
+     * Calculate the Delaunay Triangulation of the given points.
      *
-     * \param points vector of the points to triangulate
+     * If the parameter transformationFactor is not zero, the points will be
+     * transformed to calcule the triangles to get a better triangulation, but
+     * the returned mesh will consist of the original points.
+     * Every point which lies above the centroid of all points will be put away
+     * from this centroid by transformationFactor * height above the centroid.
+     * Any point below the centroid will be drawn to the centroid because its
+     * height is negative. This effect is inverted with a negative
+     * transformationFactor.
+     * This transformation is used to calculate the head surface between several
+     * electrodes, were a transformationFactor of -0.005 is reasonable.
+     *
+     * \param points               vector of the points to triangulate
+     * \param transformationFactor magnitude of the transformation before the
+     *                                 triangulation
      * \return triangulation as WTriangleMesh
      */
-    WTriangleMesh triangulate( const std::vector< wmath::WPosition >& points );
+    WTriangleMesh triangulate( const std::vector< wmath::WPosition >& points, double transformationFactor = 0.0 );
 }
 
 #endif  // WGEGEOMETRYUTILS_H

src/modules/eegView/WMEEGView.cpp

@@ -608,7 +608,7 @@ osg::ref_ptr< osg::Node > WMEEGView::drawHeadSurface()
 
     const std::size_t nbPositions = positions.size();
 
-    WTriangleMesh mesh = wge::triangulate( positions );
+    WTriangleMesh mesh = wge::triangulate( positions, -0.005 );
     osg::ref_ptr< osg::Geometry > geometry = wge::convertToOsgGeometry( &mesh, true );
 
     osg::Vec4Array* colors = new osg::Vec4Array;