310 lines
9.6 KiB
C++
310 lines
9.6 KiB
C++
/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield
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*
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* This library is open source and may be redistributed and/or modified under
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* the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
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* (at your option) any later version. The full license is in LICENSE file
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* included with this distribution, and on the openscenegraph.org website.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* OpenSceneGraph Public License for more details.
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*/
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#ifndef OSG_BOUNDINGSPHERE
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#define OSG_BOUNDINGSPHERE 1
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#include <osg/Config>
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#include <osg/Export>
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#include <osg/Vec3f>
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#include <osg/Vec3d>
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namespace osg {
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template<typename VT>
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class BoundingBoxImpl;
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/** General purpose bounding sphere class for enclosing nodes/objects/vertices.
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* Bounds internal osg::Nodes in the scene, assists in view frustum culling,
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* etc. Similar in function to BoundingBox, it's quicker for evaluating
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* culling but generally will not cull as aggressively because it encloses a
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* greater volume.
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*/
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template<typename VT>
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class BoundingSphereImpl
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{
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public:
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typedef VT vec_type;
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typedef typename VT::value_type value_type;
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vec_type _center;
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value_type _radius;
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/** Construct a default bounding sphere with radius to -1.0f, representing an invalid/unset bounding sphere.*/
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BoundingSphereImpl() : _center(0.0,0.0,0.0),_radius(-1.0) {}
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/** Creates a bounding sphere initialized to the given extents. */
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BoundingSphereImpl(const vec_type& center, value_type radius) : _center(center),_radius(radius) {}
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/** Creates a bounding sphere initialized to the given extents. */
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BoundingSphereImpl(const BoundingSphereImpl& bs) : _center(bs._center),_radius(bs._radius) {}
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/** Creates a bounding sphere initialized to the given extents. */
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BoundingSphereImpl(const BoundingBoxImpl<VT>& bb) : _center(0.0,0.0,0.0),_radius(-1.0) { expandBy(bb); }
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/** Clear the bounding sphere. Reset to default values. */
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inline void init()
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{
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_center.set(0.0,0.0,0.0);
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_radius = -1.0;
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}
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/** Returns true of the bounding sphere extents are valid, false
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* otherwise. */
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inline bool valid() const { return _radius>=0.0; }
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inline bool operator == (const BoundingSphereImpl& rhs) const { return _center==rhs._center && _radius==rhs._radius; }
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inline bool operator != (const BoundingSphereImpl& rhs) const { return _center!=rhs._center || _radius==rhs._radius; }
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/** Set the bounding sphere to the given center/radius using floats. */
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inline void set(const vec_type& center,value_type radius)
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{
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_center = center;
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_radius = radius;
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}
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/** Returns the center of the bounding sphere. */
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inline vec_type& center() { return _center; }
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/** Returns the const center of the bounding sphere. */
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inline const vec_type& center() const { return _center; }
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/** Returns the radius of the bounding sphere. */
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inline value_type& radius() { return _radius; }
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/** Returns the const radius of the bounding sphere. */
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inline value_type radius() const { return _radius; }
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/** Returns the squared length of the radius. Note, For performance
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* reasons, the calling method is responsible for checking to make
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* sure the sphere is valid. */
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inline value_type radius2() const { return _radius*_radius; }
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/** Expands the sphere to encompass the given point. Repositions the
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* sphere center to minimize the radius increase. If the sphere is
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* uninitialized, set its center to v and radius to zero. */
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template<typename vector_type>
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void expandBy(const vector_type& v);
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/** Expands the sphere to encompass the given point. Does not
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* reposition the sphere center. If the sphere is
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* uninitialized, set its center to v and radius to zero. */
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template<typename vector_type>
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void expandRadiusBy(const vector_type& v);
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/** Expands the sphere to encompass the given sphere. Repositions the
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* sphere center to minimize the radius increase. If the sphere is
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* uninitialized, set its center and radius to match sh. */
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void expandBy(const BoundingSphereImpl& sh);
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/** Expands the sphere to encompass the given sphere. Does not
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* repositions the sphere center. If the sphere is
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* uninitialized, set its center and radius to match sh. */
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void expandRadiusBy(const BoundingSphereImpl& sh);
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/** Expands the sphere to encompass the given box. Repositions the
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* sphere center to minimize the radius increase. */
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void expandBy(const BoundingBoxImpl<VT>& bb);
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/** Expands the sphere to encompass the given box. Does not
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* repositions the sphere center. */
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void expandRadiusBy(const BoundingBoxImpl<VT>& bb);
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/** Returns true if v is within the sphere. */
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inline bool contains(const vec_type& v) const
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{
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return valid() && ((v-_center).length2()<=radius2());
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}
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/** Returns true if there is a non-empty intersection with the given
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* bounding sphere. */
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inline bool intersects( const BoundingSphereImpl& bs ) const
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{
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return valid() && bs.valid() &&
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((_center - bs._center).length2() <= (_radius + bs._radius)*(_radius + bs._radius));
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}
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};
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template<typename VT>
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template<typename vector_type>
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void BoundingSphereImpl<VT>::expandBy(const vector_type& v)
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{
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if (valid())
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{
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vec_type dv = v-_center;
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value_type r = dv.length();
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if (r>_radius)
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{
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value_type dr = (r-_radius)*0.5;
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_center += dv*(dr/r);
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_radius += dr;
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} // else do nothing as vertex is within sphere.
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}
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else
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{
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_center = v;
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_radius = 0.0;
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}
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}
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template<typename VT>
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template<typename vector_type>
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void BoundingSphereImpl<VT>::expandRadiusBy(const vector_type& v)
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{
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if (valid())
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{
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value_type r = (v-_center).length();
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if (r>_radius) _radius = r;
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// else do nothing as vertex is within sphere.
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}
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else
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{
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_center = v;
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_radius = 0.0;
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}
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}
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template<typename VT>
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void BoundingSphereImpl<VT>::expandBy(const BoundingSphereImpl& sh)
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{
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// ignore operation if incomming BoundingSphere is invalid.
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if (!sh.valid()) return;
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// This sphere is not set so use the inbound sphere
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if (!valid())
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{
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_center = sh._center;
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_radius = sh._radius;
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return;
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}
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// Calculate d == The distance between the sphere centers
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double d = ( _center - sh.center() ).length();
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// New sphere is already inside this one
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if ( d + sh.radius() <= _radius )
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{
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return;
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}
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// New sphere completely contains this one
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if ( d + _radius <= sh.radius() )
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{
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_center = sh._center;
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_radius = sh._radius;
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return;
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}
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// Build a new sphere that completely contains the other two:
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//
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// The center point lies halfway along the line between the furthest
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// points on the edges of the two spheres.
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//
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// Computing those two points is ugly - so we'll use similar triangles
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double new_radius = (_radius + d + sh.radius() ) * 0.5;
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double ratio = ( new_radius - _radius ) / d ;
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_center[0] += ( sh.center()[0] - _center[0] ) * ratio;
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_center[1] += ( sh.center()[1] - _center[1] ) * ratio;
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_center[2] += ( sh.center()[2] - _center[2] ) * ratio;
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_radius = new_radius;
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}
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template<typename VT>
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void BoundingSphereImpl<VT>::expandRadiusBy(const BoundingSphereImpl& sh)
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{
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if (sh.valid())
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{
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if (valid())
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{
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value_type r = (sh._center-_center).length()+sh._radius;
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if (r>_radius) _radius = r;
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// else do nothing as vertex is within sphere.
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}
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else
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{
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_center = sh._center;
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_radius = sh._radius;
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}
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}
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}
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template<typename VT>
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void BoundingSphereImpl<VT>::expandBy(const BoundingBoxImpl<VT>& bb)
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{
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if (bb.valid())
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{
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if (valid())
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{
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BoundingBoxImpl<vec_type> newbb(bb);
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for(unsigned int c=0;c<8;++c)
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{
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vec_type v = bb.corner(c)-_center; // get the direction vector from corner
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v.normalize(); // normalise it.
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v *= -_radius; // move the vector in the opposite direction distance radius.
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v += _center; // move to absolute position.
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newbb.expandBy(v); // add it into the new bounding box.
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}
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_center = newbb.center();
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_radius = newbb.radius();
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}
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else
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{
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_center = bb.center();
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_radius = bb.radius();
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}
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}
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}
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template<typename VT>
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void BoundingSphereImpl<VT>::expandRadiusBy(const BoundingBoxImpl<VT>& bb)
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{
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if (bb.valid())
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{
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if (valid())
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{
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for(unsigned int c=0;c<8;++c)
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{
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expandRadiusBy(bb.corner(c));
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}
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}
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else
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{
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_center = bb.center();
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_radius = bb.radius();
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}
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}
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}
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typedef BoundingSphereImpl<Vec3f> BoundingSpheref;
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typedef BoundingSphereImpl<Vec3d> BoundingSphered;
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#ifdef OSG_USE_FLOAT_BOUNDINGSPHERE
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typedef BoundingSpheref BoundingSphere;
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#else
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typedef BoundingSphered BoundingSphere;
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#endif
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}
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#endif
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