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306 lines
9.5 KiB
306 lines
9.5 KiB
/* -*-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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/** 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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