1 // ball.h (A n-dimensional ball)
2 //
3 // The WorldForge Project
4 // Copyright (C) 2000, 2001 The WorldForge Project
5 //
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22 //
23
24 // Author: Ron Steinke
25
26 #ifndef WFMATH_BALL_H
27 #define WFMATH_BALL_H
28
29 #include <wfmath/point.h>
30 #include <wfmath/intersect_decls.h>
31
32 namespace WFMath {
33
34 template<int dim> class Ball;
35
36 /// get the minimal bounding sphere for a set of points
37 template<int dim, template<class, class> class container>
38 Ball<dim> BoundingSphere(const container<Point<dim>, std::allocator<Point<dim> > >& c);
39 /// get a bounding sphere for a set of points
40 template<int dim, template<class, class> class container>
41 Ball<dim> BoundingSphereSloppy(const container<Point<dim>, std::allocator<Point<dim> > >& c);
42
43 template<int dim>
44 std::ostream& operator<<(std::ostream& os, const Ball<dim>& m);
45 template<int dim>
46 std::istream& operator>>(std::istream& is, Ball<dim>& m);
47
48 /// A dim dimensional ball
49 /**
50 * This class implements the full shape interface, as described in
51 * the fake class Shape.
52 *
53 * This class is called Ball<> instead of Sphere to be more in tune
54 * with the usual mathematical naming conventions, where a ball is
55 * a filled object, while a sphere is just the outer shell. It also
56 * helps that a Ball<n> corresponds to an n-ball, while a Sphere<n>
57 * would correspond to an (n-1)-sphere.
58 **/
59 template<int dim = 3>
60 class Ball
61 {
62 public:
63 /// construct an uninitialized ball
Ball()64 Ball() : m_center(), m_radius(0.f) {}
65 /// construct a ball with the given center and radius
Ball(const Point<dim> & center,CoordType radius)66 Ball(const Point<dim>& center, CoordType radius)
67 : m_center(center), m_radius(radius) { if (radius < 0) m_center.setValid(false); }
68 /// construct a copy of a ball
Ball(const Ball & b)69 Ball(const Ball& b) : m_center(b.m_center), m_radius(b.m_radius) {}
70 /// Construct a ball from an object passed by Atlas
71 explicit Ball(const AtlasInType& a);
72
~Ball()73 ~Ball() {}
74
75 friend std::ostream& operator<< <dim>(std::ostream& os, const Ball& b);
76 friend std::istream& operator>> <dim>(std::istream& is, Ball& b);
77
78 /// Create an Atlas object from the box
79 AtlasOutType toAtlas() const;
80 /// Set the box's value to that given by an Atlas object
81 void fromAtlas(const AtlasInType& a);
82
83 Ball& operator=(const Ball& b)
84 {m_radius = b.m_radius; m_center = b.m_center; return *this;}
85
86 bool isEqualTo(const Ball& b, CoordType epsilon = numeric_constants<CoordType>::epsilon()) const;
87
88 bool operator==(const Ball& b) const {return isEqualTo(b);}
89 bool operator!=(const Ball& b) const {return !isEqualTo(b);}
90
isValid()91 bool isValid() const {return m_center.isValid();}
92
93 // Descriptive characteristics
94
numCorners()95 size_t numCorners() const {return 0;}
96 // This next function exists so that Ball can be used by code
97 // that finds the number of corners with numCorners(), and does something
98 // with each corner with getCorner(). No idea how useful that is, but
99 // it's not a particularly complicated function to write.
getCorner(size_t)100 Point<dim> getCorner(size_t) const {return m_center;}
getCenter()101 Point<dim> getCenter() const {return m_center;}
102
103 /// get the center of the ball
center()104 const Point<dim>& center() const {return m_center;}
105 /// get the center of the ball
center()106 Point<dim>& center() {return m_center;}
107 /// get the radius of the ball
radius()108 CoordType radius() const {return m_radius;}
109 /// get the radius of the ball
radius()110 CoordType& radius() {return m_radius;}
111
112 // Movement functions
113
shift(const Vector<dim> & v)114 Ball& shift(const Vector<dim>& v) {m_center += v; return *this;}
moveCornerTo(const Point<dim> &,size_t)115 Ball& moveCornerTo(const Point<dim>&, size_t) {return *this;}
moveCenterTo(const Point<dim> & p)116 Ball& moveCenterTo(const Point<dim>& p) {m_center = p; return *this;}
117
rotateCorner(const RotMatrix<dim> &,size_t)118 Ball& rotateCorner(const RotMatrix<dim>&, size_t) {return *this;}
rotateCenter(const RotMatrix<dim> &)119 Ball& rotateCenter(const RotMatrix<dim>&) {return *this;}
rotatePoint(const RotMatrix<dim> & m,const Point<dim> & p)120 Ball& rotatePoint(const RotMatrix<dim>& m, const Point<dim>& p)
121 {m_center.rotate(m, p); return *this;}
122
123 // 3D rotation function
124 Ball& rotateCorner(const Quaternion&, size_t corner);
125 Ball& rotateCenter(const Quaternion&);
126 Ball& rotatePoint(const Quaternion& q, const Point<dim>& p);
127
128 // Intersection functions
129
130 AxisBox<dim> boundingBox() const;
boundingSphere()131 Ball boundingSphere() const {return *this;}
boundingSphereSloppy()132 Ball boundingSphereSloppy() const {return *this;}
133
134 Ball toParentCoords(const Point<dim>& origin,
135 const RotMatrix<dim>& rotation = RotMatrix<dim>().identity()) const
136 {return Ball(m_center.toParentCoords(origin, rotation), m_radius);}
toParentCoords(const AxisBox<dim> & coords)137 Ball toParentCoords(const AxisBox<dim>& coords) const
138 {return Ball(m_center.toParentCoords(coords), m_radius);}
toParentCoords(const RotBox<dim> & coords)139 Ball toParentCoords(const RotBox<dim>& coords) const
140 {return Ball(m_center.toParentCoords(coords), m_radius);}
141
142 // toLocal is just like toParent, expect we reverse the order of
143 // translation and rotation and use the opposite sense of the rotation
144 // matrix
145
146 Ball toLocalCoords(const Point<dim>& origin,
147 const RotMatrix<dim>& rotation = RotMatrix<dim>().identity()) const
148 {return Ball(m_center.toLocalCoords(origin, rotation), m_radius);}
toLocalCoords(const AxisBox<dim> & coords)149 Ball toLocalCoords(const AxisBox<dim>& coords) const
150 {return Ball(m_center.toLocalCoords(coords), m_radius);}
toLocalCoords(const RotBox<dim> & coords)151 Ball toLocalCoords(const RotBox<dim>& coords) const
152 {return Ball(m_center.toLocalCoords(coords), m_radius);}
153
154 // 3D only
155 Ball toParentCoords(const Point<dim>& origin, const Quaternion& rotation) const;
156 Ball toLocalCoords(const Point<dim>& origin, const Quaternion& rotation) const;
157
158 friend bool Intersect<dim>(const Ball& b, const Point<dim>& p, bool proper);
159 friend bool Contains<dim>(const Point<dim>& p, const Ball& b, bool proper);
160
161 friend bool Intersect<dim>(const Ball& b, const AxisBox<dim>& a, bool proper);
162 friend bool Contains<dim>(const Ball& b, const AxisBox<dim>& a, bool proper);
163 friend bool Contains<dim>(const AxisBox<dim>& a, const Ball& b, bool proper);
164
165 friend bool Intersect<dim>(const Ball& b1, const Ball& b2, bool proper);
166 friend bool Contains<dim>(const Ball& outer, const Ball& inner, bool proper);
167
168 friend bool Intersect<dim>(const Segment<dim>& s, const Ball& b, bool proper);
169 friend bool Contains<dim>(const Segment<dim>& s, const Ball& b, bool proper);
170
171 friend bool Intersect<dim>(const RotBox<dim>& r, const Ball& b, bool proper);
172 friend bool Contains<dim>(const RotBox<dim>& r, const Ball& b, bool proper);
173 friend bool Contains<dim>(const Ball& b, const RotBox<dim>& r, bool proper);
174
175 friend bool Intersect<dim>(const Polygon<dim>& p, const Ball& b, bool proper);
176 friend bool Contains<dim>(const Polygon<dim>& p, const Ball& b, bool proper);
177 friend bool Contains<dim>(const Ball& b, const Polygon<dim>& p, bool proper);
178
179 private:
180
181 Point<dim> m_center;
182 CoordType m_radius;
183 };
184
185 template<int dim>
isEqualTo(const Ball<dim> & b,CoordType epsilon)186 inline bool Ball<dim>::isEqualTo(const Ball<dim>& b, CoordType epsilon) const
187 {
188 return Equal(m_center, b.m_center, epsilon)
189 && Equal(m_radius, b.m_radius, epsilon);
190 }
191
192 } // namespace WFMath
193
194 #endif // WFMATH_BALL_H
195