sphere-inl.h

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#ifndef FCL_SHAPE_SPHERE_INL_H
#define FCL_SHAPE_SPHERE_INL_H

#include "fcl/geometry/shape/sphere.h"

namespace fcl
{

//==============================================================================
extern template
class Sphere<double>;

//==============================================================================
template <typename S>
Sphere<S>::Sphere(S radius) : ShapeBase<S>(), radius(radius)
{
}

//==============================================================================
template <typename S>
void Sphere<S>::computeLocalAABB()
{
  this->aabb_local.max_.setConstant(radius);
  this->aabb_local.min_.setConstant(-radius);

  this->aabb_center = this->aabb_local.center();
  this->aabb_radius = radius;
}

//==============================================================================
template <typename S>
NODE_TYPE Sphere<S>::getNodeType() const
{
  return GEOM_SPHERE; }

//==============================================================================
template <typename S>
Matrix3<S> Sphere<S>::computeMomentofInertia() const
{
  S I = (S)0.4 * radius * radius * computeVolume();

  return Vector3<S>::Constant(I).asDiagonal();
}

//==============================================================================
template <typename S>
S Sphere<S>::computeVolume() const
{
  return (S)4.0 * constants<S>::pi() * radius * radius * radius / (S)3.0;
}

//==============================================================================
template <typename S>
std::vector<Vector3<S>> Sphere<S>::getBoundVertices(
    const Transform3<S>& tf) const
{
  // we use icosahedron to bound the sphere

  std::vector<Vector3<S>> result(12);
  const auto m = (1 + std::sqrt(5.0)) / 2.0;
  auto edge_size = radius * 6 / (std::sqrt(27.0) + std::sqrt(15.0));

  auto a = edge_size;
  auto b = m * edge_size;
  result[0] = tf * Vector3<S>(0, a, b);
  result[1] = tf * Vector3<S>(0, -a, b);
  result[2] = tf * Vector3<S>(0, a, -b);
  result[3] = tf * Vector3<S>(0, -a, -b);
  result[4] = tf * Vector3<S>(a, b, 0);
  result[5] = tf * Vector3<S>(-a, b, 0);
  result[6] = tf * Vector3<S>(a, -b, 0);
  result[7] = tf * Vector3<S>(-a, -b, 0);
  result[8] = tf * Vector3<S>(b, 0, a);
  result[9] = tf * Vector3<S>(b, 0, -a);
  result[10] = tf * Vector3<S>(-b, 0, a);
  result[11] = tf * Vector3<S>(-b, 0, -a);

  return result;
}

} // namespace fcl

#endif