anki-3d-engine/ThirdParty/Bullet/Extras/InverseDynamics/CoilCreator.hpp

#ifndef COILCREATOR_HPP_
#define COILCREATOR_HPP_

#include "MultiBodyTreeCreator.hpp"

namespace btInverseDynamics
{
/// Creator class for building a "coil" system as intruduced as benchmark example in
/// Featherstone (1999), "A Divide-and-Conquer Articulated-Body Algorithm for Parallel O(log(n))
/// Calculation of Rigid-Body Dynamics. Part 2: Trees, Loops, and Accuracy.",  The International
/// Journal of Robotics Research 18 (9): 876–892. doi : 10.1177 / 02783649922066628.
///
/// This is a serial chain, with an initial configuration resembling a coil.
class CoilCreator : public MultiBodyTreeCreator
{
public:
	/// ctor.
	/// @param n the number of bodies in the system
	CoilCreator(int n);
	/// dtor
	~CoilCreator();
	// \copydoc MultiBodyTreeCreator::getNumBodies
	int getNumBodies(int* num_bodies) const;
	// \copydoc MultiBodyTreeCreator::getBody
	int getBody(const int body_index, int* parent_index, JointType* joint_type,
				vec3* parent_r_parent_body_ref, mat33* body_T_parent_ref, vec3* body_axis_of_motion,
				idScalar* mass, vec3* body_r_body_com, mat33* body_I_body, int* user_int,
				void** user_ptr) const;

private:
	int m_num_bodies;
	std::vector<int> m_parent;
	vec3 m_parent_r_parent_body_ref;
	mat33 m_body_T_parent_ref;
	vec3 m_body_axis_of_motion;
	idScalar m_mass;
	vec3 m_body_r_body_com;
	mat33 m_body_I_body;
};
}  // namespace btInverseDynamics
#endif