EgtGraphics 1.6v7 :

- migliorie varie per overload e const
- aggiunta GetPlaneSnapPoint.

SceneSnap.cpp

@@ -70,7 +70,7 @@ Scene::GetGraphicSnapPoint( int nSnap, const Point3d& ptWin, int nW, int nH, Poi
 
 //----------------------------------------------------------------------------
 bool
-Scene::GetGridSnapPointZ( bool bSketch, const Point3d& ptWin, const Point3d& ptGrid, Point3d& ptSel)
+Scene::GetGridSnapPointZ( bool bSketch, const Point3d& ptWin, const Point3d& ptGrid, Point3d& ptSel) const
 {
   // recupero il riferimento di griglia
    Frame3d frGrid = GetGridFrame() ;
@@ -468,7 +468,7 @@ Scene::FindCurveSnapPoint( int nSnap, const Point3d& ptWin, int nId, const Frame
 
 //----------------------------------------------------------------------------
 bool
-Scene::VerifySnapPoint( const Point3d& ptP, const Point3d& ptWin, double& dMinSqDist)
+Scene::VerifySnapPoint( const Point3d& ptP, const Point3d& ptWin, double& dMinSqDist) const
 {
   // il punto di riferimento deriva da XY su viewport e Z minima (più vicina a osservatore) da selezione 
    Point3d ptWinZ( ptWin.x, ptWin.y, GetSelectedObjMinWinZ()) ;
@@ -962,4 +962,23 @@ Scene::FindTextSnapPoint( int nSnap, const Point3d& ptWin, int nId, const Frame3
       break ;
    }
    return bFound ;
-}
+}
+
+//----------------------------------------------------------------------------
+bool
+Scene::GetPlaneSnapPoint( const Point3d& ptWin, const Plane3d& plPlane, Point3d& ptSel) const
+{
+  // calcolo un punto e la direzione della linea di mira
+   Point3d ptLine ;
+   if ( ! UnProject( ptWin, ptLine))
+      return false ;
+   Vector3d vtLine = - m_vtDirCamera ;
+
+  // determino l'intersezione di questa linea con il piano
+   double dDenom = vtLine * plPlane.vtN ;
+   if ( fabs( dDenom) < COS_ORTO_ANG_ZERO)
+      return false ;
+   double dU = ( plPlane.dDist - ( ptLine - ORIG) * plPlane.vtN) / dDenom ;
+   ptSel = ptLine + dU * vtLine ;
+   return true ;
+}