Changeset 9268 for OpenSceneGraph/trunk/include/osg/BoundingSphere

Timestamp:

11/26/08 17:39:52 (3 years ago)

Author:

robert

Message:

From Tim Moore, "Double precision versions of BoundingBox? and BoundingSphere? are useful for doing computations in world coordinates, especially when working with a geocentric scene. By default, these classes are built using floats, so templated versions fill a need. I've used the double precision templates to fix some problems with ViewDependentShadow?, which will follow shortly.
"

Files:

• OpenSceneGraph/trunk/include/osg/BoundingSphere (modified) (4 diffs)

OpenSceneGraph/trunk/include/osg/BoundingSphere

@@ -22 +22 @@
 namespace osg {
 
-class BoundingBox;
+template<typename VT>
+class BoundingBoxImpl;
 
 /** General purpose bounding sphere class for enclosing nodes/objects/vertices.
@@ -30 +31 @@
   * greater volume.
 */
-class OSG_EXPORT BoundingSphere
+template<typename VT>
+class BoundingSphereImpl
 {
     public:
-
-#ifdef OSG_USE_FLOAT_BOUNDINGSPHERE
-        typedef Vec3f vec_type;
-        typedef float value_type;
-#else
-        typedef Vec3d vec_type;
-        typedef double value_type;
-#endif
-        
+        typedef VT vec_type;
+        typedef typename vec_type::value_type value_type;        
+
         vec_type    _center;
         value_type  _radius;
 
         /** Construct a default bounding sphere with radius to -1.0f, representing an invalid/unset bounding sphere.*/ 
-        BoundingSphere() : _center(0.0,0.0,0.0),_radius(-1.0) {}
+        BoundingSphereImpl() : _center(0.0,0.0,0.0),_radius(-1.0) {}
     
         /** Creates a bounding sphere initialized to the given extents. */
-        BoundingSphere(const vec_type& center,value_type radius) : _center(center),_radius(radius) {}
+        BoundingSphereImpl(const vec_type& center,value_type radius) : _center(center),_radius(radius) {}
 
         /** Creates a bounding sphere initialized to the given extents. */
-        BoundingSphere(const BoundingSphere& bs) : _center(bs._center),_radius(bs._radius) {}
+        BoundingSphereImpl(const BoundingSphereImpl& bs) : _center(bs._center),_radius(bs._radius) {}
 
         /** Creates a bounding sphere initialized to the given extents. */
-        BoundingSphere(const BoundingBox& bb) : _center(0.0,0.0,0.0),_radius(-1.0) { expandBy(bb); }
+        BoundingSphereImpl(const BoundingBoxImpl<VT>& bb) : _center(0.0,0.0,0.0),_radius(-1.0) { expandBy(bb); }
 
         /** Clear the bounding sphere. Reset to default values. */
@@ -94 +90 @@
           * sphere center to minimize the radius increase. If the sphere is
           * uninitialized, set its center to v and radius to zero. */
-        void expandBy(const Vec3f& v);
+        template<typename vector_type>
+        void expandBy(const vector_type& v);
 
         /** Expands the sphere to encompass the given point. Does not
           * reposition the sphere center. If the sphere is
           * uninitialized, set its center to v and radius to zero. */
-        void expandRadiusBy(const Vec3f& v);
-
-        /** Expands the sphere to encompass the given point. Repositions the
-          * sphere center to minimize the radius increase. If the sphere is
-          * uninitialized, set its center to v and radius to zero. */
-        void expandBy(const Vec3d& v);
-
-        /** Expands the sphere to encompass the given point. Does not
-          * reposition the sphere center. If the sphere is
-          * uninitialized, set its center to v and radius to zero. */
-        void expandRadiusBy(const Vec3d& v);
+        template<typename vector_type>
+        void expandRadiusBy(const vector_type& v);
 
         /** Expands the sphere to encompass the given sphere. Repositions the
           * sphere center to minimize the radius increase. If the sphere is
           * uninitialized, set its center and radius to match sh. */
-        void expandBy(const BoundingSphere& sh);
+        void expandBy(const BoundingSphereImpl& sh);
 
         /** Expands the sphere to encompass the given sphere. Does not
           * repositions the sphere center. If the sphere is
           * uninitialized, set its center and radius to match sh. */
-        void expandRadiusBy(const BoundingSphere& sh);
+        void expandRadiusBy(const BoundingSphereImpl& sh);
 
         /** Expands the sphere to encompass the given box. Repositions the
           * sphere center to minimize the radius increase. */
-        void expandBy(const BoundingBox& bb);
+        void expandBy(const BoundingBoxImpl<VT>& bb);
 
         /** Expands the sphere to encompass the given box. Does not
           * repositions the sphere center. */
-        void expandRadiusBy(const BoundingBox& bb);
+        void expandRadiusBy(const BoundingBoxImpl<VT>& bb);
 
         /** Returns true if v is within the sphere. */
@@ -138 +126 @@
         /** Returns true if there is a non-empty intersection with the given
           * bounding sphere. */
-        inline bool intersects( const BoundingSphere& bs ) const
+        inline bool intersects( const BoundingSphereImpl& bs ) const
         {
             return valid() && bs.valid() &&
                    ((_center - bs._center).length2() <= (_radius + bs._radius)*(_radius + bs._radius));
         }
-
+        
 };
 
-}
-
+
+template<typename VT>
+ template<typename vector_type>
+void BoundingSphereImpl<VT>::expandBy(const vector_type& v)
+{
+    if (valid())
+    {
+        vec_type dv = v-_center;
+        value_type r = dv.length();
+        if (r>_radius)
+        {
+            value_type dr = (r-_radius)*0.5;
+            _center += dv*(dr/r);
+            _radius += dr;
+        } // else do nothing as vertex is within sphere.
+    }
+    else
+    {
+        _center = v;
+        _radius = 0.0;
+    }
+}
+
+template<typename VT>
+ template<typename vector_type>
+void BoundingSphereImpl<VT>::expandRadiusBy(const vector_type& v)
+{
+    if (valid())
+    {
+        value_type r = (v-_center).length();
+        if (r>_radius) _radius = r;
+        // else do nothing as vertex is within sphere.
+    }
+    else
+    {
+        _center = v;
+        _radius = 0.0;
+    }
+}
+
+template<typename VT>
+void BoundingSphereImpl<VT>::expandBy(const BoundingSphereImpl& sh)
+{
+    // ignore operation if incomming BoundingSphere is invalid.
+    if (!sh.valid()) return;
+
+    // This sphere is not set so use the inbound sphere
+    if (!valid())
+    {
+        _center = sh._center;
+        _radius = sh._radius;
+
+        return;
+    }
+    
+    
+    // Calculate d == The distance between the sphere centers   
+    double d = ( _center - sh.center() ).length();
+
+    // New sphere is already inside this one
+    if ( d + sh.radius() <= _radius )  
+    {
+        return;
+    }
+
+    //  New sphere completely contains this one 
+    if ( d + _radius <= sh.radius() )  
+    {
+        _center = sh._center;
+        _radius = sh._radius;
+        return;
+    }
+
+    
+    // Build a new sphere that completely contains the other two:
+    //
+    // The center point lies halfway along the line between the furthest
+    // points on the edges of the two spheres.
+    //
+    // Computing those two points is ugly - so we'll use similar triangles
+    double new_radius = (_radius + d + sh.radius() ) * 0.5;
+    double ratio = ( new_radius - _radius ) / d ;
+
+    _center[0] += ( sh.center()[0] - _center[0] ) * ratio;
+    _center[1] += ( sh.center()[1] - _center[1] ) * ratio;
+    _center[2] += ( sh.center()[2] - _center[2] ) * ratio;
+
+    _radius = new_radius;
+
+}
+
+template<typename VT>
+void BoundingSphereImpl<VT>::expandRadiusBy(const BoundingSphereImpl& sh)
+{
+    if (sh.valid())
+    {
+        if (valid())
+        {
+            value_type r = (sh._center-_center).length()+sh._radius;
+            if (r>_radius) _radius = r;
+            // else do nothing as vertex is within sphere.
+        }
+        else
+        {
+            _center = sh._center;
+            _radius = sh._radius;
+        }
+    }
+}
+
+template<typename VT>        
+void BoundingSphereImpl<VT>::expandBy(const BoundingBoxImpl<VT>& bb)
+{
+    if (bb.valid())
+    {
+        if (valid())
+        {
+            BoundingBoxImpl<vec_type> newbb(bb);
+
+            for(unsigned int c=0;c<8;++c)
+            {
+                vec_type v = bb.corner(c)-_center; // get the direction vector from corner
+                v.normalize(); // normalise it.
+                v *= -_radius; // move the vector in the opposite direction distance radius.
+                v += _center; // move to absolute position.
+                newbb.expandBy(v); // add it into the new bounding box.
+            }
+            
+            _center = newbb.center();
+            _radius = newbb.radius();
+            
+        }
+        else
+        {
+            _center = bb.center();
+            _radius = bb.radius();
+        }
+    }
+}
+
+template<typename VT>
+void BoundingSphereImpl<VT>::expandRadiusBy(const BoundingBoxImpl<VT>& bb)
+{
+    if (bb.valid())
+    {
+        if (valid())
+        {
+            for(unsigned int c=0;c<8;++c)
+            {
+                expandRadiusBy(bb.corner(c));
+            }
+        }
+        else
+        {
+            _center = bb.center();
+            _radius = bb.radius();
+        }
+    }
+}
+
+typedef BoundingSphereImpl<Vec3f> BoundingSpheref;
+typedef BoundingSphereImpl<Vec3d> BoundingSphered;
+
+#ifdef OSG_USE_FLOAT_BOUNDINGSPHERE
+        typedef BoundingSpheref BoundingSphere;
+#else
+        typedef BoundingSphered BoundingSphere;        
 #endif
+}
+
+#endif