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BoundingBoxOriented.h
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1 /* Copyright (C) 2011 Wildfire Games.
2  * This file is part of 0 A.D.
3  *
4  * 0 A.D. is free software: you can redistribute it and/or modify
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8  *
9  * 0 A.D. is distributed in the hope that it will be useful,
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11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
16  */
17 
18 #ifndef INCLUDED_BOX
19 #define INCLUDED_BOX
20 
21 #include "maths/Vector3D.h"
22 
24 
25 /*
26  * Generic oriented box. Originally intended to be used an Oriented Bounding Box (OBB),
27  * as opposed to CBoundingBoxAligned which is always aligned to the world-space axes (AABB).
28  * However, it could also be used to represent more generic shapes, such as parallelepipeds.
29  */
31 {
32 public:
33 
34  /// Empty constructor; creates an empty box
36 
37  /**
38  * Constructs a new oriented box centered at @p center and with normalized side vectors @p u,
39  * @p v and @p w. These vectors should be mutually orthonormal for a proper rectangular box.
40  * The half-widths of the box in each dimension are given by the corresponding components of
41  * @p halfSizes.
42  */
43  CBoundingBoxOriented(const CVector3D& center, const CVector3D& u, const CVector3D& v, const CVector3D& w, const CVector3D& halfSizes)
44  : m_Center(center), m_HalfSizes(halfSizes)
45  {
46  m_Basis[0] = u;
47  m_Basis[1] = v;
48  m_Basis[2] = w;
49  }
50 
51  /// Constructs a new box from an axis-aligned bounding box (AABB).
52  explicit CBoundingBoxOriented(const CBoundingBoxAligned& bound);
53 
54  /**
55  * Check if a given ray intersects this box. Must not be used if IsEmpty() is true.
56  * See Real-Time Rendering, Third Edition by T. Akenine-Moller, p. 741--744.
57  *
58  * @param[in] origin Origin of the ray.
59  * @param[in] dir Direction vector of the ray, defining the positive direction of the ray.
60  * Must be of unit length.
61  * @param[out] tMin,tMax Distance in the positive direction from the origin of the ray to the
62  * entry and exit points in the box, provided that the ray intersects the box. if
63  * the ray does not intersect the box, no values are written to these variables.
64  * If the origin is inside the box, then this is counted as an intersection and one
65  * of @p tMin and @p tMax may be negative.
66  *
67  * @return true If the ray originating in @p origin and with unit direction vector @p dir intersects
68  * this box, false otherwise.
69  */
70  bool RayIntersect(const CVector3D& origin, const CVector3D& dir, float& tMin, float& tMax) const;
71 
72  /**
73  * Returns the corner at coordinate (@p u, @p v, @p w). Each of @p u, @p v and @p w must be exactly 1 or -1.
74  * Must not be used if IsEmpty() is true.
75  */
76  void GetCorner(int u, int v, int w, CVector3D& out) const
77  {
78  out = m_Center + m_Basis[0]*(u*m_HalfSizes[0]) + m_Basis[1]*(v*m_HalfSizes[1]) + m_Basis[2]*(w*m_HalfSizes[2]);
79  }
80 
81  void SetEmpty()
82  {
83  // everything is zero
84  m_Center = CVector3D();
85  m_Basis[0] = CVector3D();
86  m_Basis[1] = CVector3D();
87  m_Basis[2] = CVector3D();
89  }
90 
91  bool IsEmpty() const
92  {
93  CVector3D empty;
94  return (m_Center == empty &&
95  m_Basis[0] == empty &&
96  m_Basis[1] == empty &&
97  m_Basis[2] == empty &&
98  m_HalfSizes == empty);
99  }
100 
101 public:
102  CVector3D m_Center; ///< Centroid location of the box
103  CVector3D m_HalfSizes; ///< Half the sizes of the box in each dimension (u,v,w). Positive values are expected.
104  /// Basis vectors (u,v,w) of the sides. Must always be normalized, and should be
105  /// orthogonal for a proper rectangular cuboid.
107 
109 };
110 
111 #endif // INCLUDED_BOX
static void out(const wchar_t *fmt,...)
Definition: wdbg_sym.cpp:421
Definition: Vector3D.h:30
CVector3D m_Center
Centroid location of the box.
Definition: BoundingBoxOriented.h:102
bool RayIntersect(const CVector3D &origin, const CVector3D &dir, float &tMin, float &tMax) const
Check if a given ray intersects this box.
Definition: BoundingBoxOriented.cpp:47
CVector3D m_Basis[3]
Basis vectors (u,v,w) of the sides.
Definition: BoundingBoxOriented.h:106
static const CBoundingBoxOriented EMPTY
Definition: BoundingBoxOriented.h:108
void GetCorner(int u, int v, int w, CVector3D &out) const
Returns the corner at coordinate (u, v, w).
Definition: BoundingBoxOriented.h:76
CVector3D m_HalfSizes
Half the sizes of the box in each dimension (u,v,w).
Definition: BoundingBoxOriented.h:103
CBoundingBoxOriented()
Empty constructor; creates an empty box.
Definition: BoundingBoxOriented.h:35
Definition: BoundingBoxAligned.h:33
bool IsEmpty() const
Definition: BoundingBoxOriented.h:91
Definition: BoundingBoxOriented.h:30
void SetEmpty()
Definition: BoundingBoxOriented.h:81
CBoundingBoxOriented(const CVector3D &center, const CVector3D &u, const CVector3D &v, const CVector3D &w, const CVector3D &halfSizes)
Constructs a new oriented box centered at center and with normalized side vectors u...
Definition: BoundingBoxOriented.h:43