FCL  0.6.0
Flexible Collision Library
sphere-inl.h
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35 
38 #ifndef FCL_SHAPE_SPHERE_INL_H
39 #define FCL_SHAPE_SPHERE_INL_H
40 
41 #include "fcl/geometry/shape/sphere.h"
42 
43 namespace fcl
44 {
45 
46 //==============================================================================
47 extern template
48 class Sphere<double>;
49 
50 //==============================================================================
51 template <typename S>
52 Sphere<S>::Sphere(S radius) : ShapeBase<S>(), radius(radius)
53 {
54 }
55 
56 //==============================================================================
57 template <typename S>
59 {
60  this->aabb_local.max_.setConstant(radius);
61  this->aabb_local.min_.setConstant(-radius);
62 
63  this->aabb_center = this->aabb_local.center();
64  this->aabb_radius = radius;
65 }
66 
67 //==============================================================================
68 template <typename S>
70 {
71  return GEOM_SPHERE; }
72 
73 //==============================================================================
74 template <typename S>
76 {
77  S I = (S)0.4 * radius * radius * computeVolume();
78 
79  return Vector3<S>::Constant(I).asDiagonal();
80 }
81 
82 //==============================================================================
83 template <typename S>
85 {
86  return (S)4.0 * constants<S>::pi() * radius * radius * radius / (S)3.0;
87 }
88 
89 //==============================================================================
90 template <typename S>
91 std::vector<Vector3<S>> Sphere<S>::getBoundVertices(
92  const Transform3<S>& tf) const
93 {
94  // we use icosahedron to bound the sphere
95 
96  std::vector<Vector3<S>> result(12);
97  const auto m = (1 + std::sqrt(5.0)) / 2.0;
98  auto edge_size = radius * 6 / (std::sqrt(27.0) + std::sqrt(15.0));
99 
100  auto a = edge_size;
101  auto b = m * edge_size;
102  result[0] = tf * Vector3<S>(0, a, b);
103  result[1] = tf * Vector3<S>(0, -a, b);
104  result[2] = tf * Vector3<S>(0, a, -b);
105  result[3] = tf * Vector3<S>(0, -a, -b);
106  result[4] = tf * Vector3<S>(a, b, 0);
107  result[5] = tf * Vector3<S>(-a, b, 0);
108  result[6] = tf * Vector3<S>(a, -b, 0);
109  result[7] = tf * Vector3<S>(-a, -b, 0);
110  result[8] = tf * Vector3<S>(b, 0, a);
111  result[9] = tf * Vector3<S>(b, 0, -a);
112  result[10] = tf * Vector3<S>(-b, 0, a);
113  result[11] = tf * Vector3<S>(-b, 0, -a);
114 
115  return result;
116 }
117 
118 } // namespace fcl
119 
120 #endif
Vector3< S_ > aabb_center
AABB center in local coordinate.
Definition: collision_geometry.h:91
NODE_TYPE
traversal node type: bounding volume (AABB, OBB, RSS, kIOS, OBBRSS, KDOP16, KDOP18, kDOP24), basic shape (box, sphere, ellipsoid, capsule, cone, cylinder, convex, plane, halfspace, triangle), and octree
Definition: collision_geometry.h:54
Main namespace.
Definition: broadphase_bruteforce-inl.h:45
S_ aabb_radius
AABB radius.
Definition: collision_geometry.h:94
Matrix3< S > computeMomentofInertia() const override
compute the inertia matrix, related to the origin
Definition: sphere-inl.h:75
std::vector< Vector3< S > > getBoundVertices(const Transform3< S > &tf) const
get the vertices of some convex shape which can bound this shape in a specific configuration ...
Definition: sphere-inl.h:91
static constexpr S pi()
The mathematical constant pi.
Definition: constants.h:49
AABB< S_ > aabb_local
AABB in local coordinate, used for tight AABB when only translation transform.
Definition: collision_geometry.h:97
void computeLocalAABB() override
Compute AABB<S>
Definition: sphere-inl.h:58
virtual S_ computeVolume() const
compute the volume
S computeVolume() const override
compute the volume
Definition: sphere-inl.h:84
NODE_TYPE getNodeType() const override
Get node type: a sphere.
Definition: sphere-inl.h:69