245 lines
8.9 KiB
C++
245 lines
8.9 KiB
C++
/*
|
|
Bullet Continuous Collision Detection and Physics Library
|
|
Copyright (c) 2013 Erwin Coumans http://bulletphysics.org
|
|
|
|
This software is provided 'as-is', without any express or implied warranty.
|
|
In no event will the authors be held liable for any damages arising from the use of this software.
|
|
Permission is granted to anyone to use this software for any purpose,
|
|
including commercial applications, and to alter it and redistribute it freely,
|
|
subject to the following restrictions:
|
|
|
|
1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
|
|
2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
|
|
3. This notice may not be removed or altered from any source distribution.
|
|
*/
|
|
|
|
#ifndef BT_MULTIBODY_LINK_H
|
|
#define BT_MULTIBODY_LINK_H
|
|
|
|
#include "LinearMath/btQuaternion.h"
|
|
#include "LinearMath/btVector3.h"
|
|
#include "BulletCollision/CollisionDispatch/btCollisionObject.h"
|
|
|
|
enum btMultiBodyLinkFlags
|
|
{
|
|
BT_MULTIBODYLINKFLAGS_DISABLE_PARENT_COLLISION = 1,
|
|
BT_MULTIBODYLINKFLAGS_DISABLE_ALL_PARENT_COLLISION = 2,
|
|
};
|
|
|
|
//both defines are now permanently enabled
|
|
#define BT_MULTIBODYLINK_INCLUDE_PLANAR_JOINTS
|
|
#define TEST_SPATIAL_ALGEBRA_LAYER
|
|
|
|
//
|
|
// Various spatial helper functions
|
|
//
|
|
|
|
//namespace {
|
|
|
|
|
|
#include "LinearMath/btSpatialAlgebra.h"
|
|
|
|
//}
|
|
|
|
//
|
|
// Link struct
|
|
//
|
|
|
|
struct btMultibodyLink
|
|
{
|
|
|
|
BT_DECLARE_ALIGNED_ALLOCATOR();
|
|
|
|
btScalar m_mass; // mass of link
|
|
btVector3 m_inertiaLocal; // inertia of link (local frame; diagonal)
|
|
|
|
int m_parent; // index of the parent link (assumed to be < index of this link), or -1 if parent is the base link.
|
|
|
|
btQuaternion m_zeroRotParentToThis; // rotates vectors in parent-frame to vectors in local-frame (when q=0). constant.
|
|
|
|
btVector3 m_dVector; // vector from the inboard joint pos to this link's COM. (local frame.) constant.
|
|
//this is set to zero for planar joint (see also m_eVector comment)
|
|
|
|
// m_eVector is constant, but depends on the joint type:
|
|
// revolute, fixed, prismatic, spherical: vector from parent's COM to the pivot point, in PARENT's frame.
|
|
// planar: vector from COM of parent to COM of this link, WHEN Q = 0. (local frame.)
|
|
// todo: fix the planar so it is consistent with the other joints
|
|
|
|
btVector3 m_eVector;
|
|
|
|
btSpatialMotionVector m_absFrameTotVelocity, m_absFrameLocVelocity;
|
|
|
|
enum eFeatherstoneJointType
|
|
{
|
|
eRevolute = 0,
|
|
ePrismatic = 1,
|
|
eSpherical = 2,
|
|
ePlanar = 3,
|
|
eFixed = 4,
|
|
eInvalid
|
|
};
|
|
|
|
|
|
|
|
// "axis" = spatial joint axis (Mirtich Defn 9 p104). (expressed in local frame.) constant.
|
|
// for prismatic: m_axesTop[0] = zero;
|
|
// m_axesBottom[0] = unit vector along the joint axis.
|
|
// for revolute: m_axesTop[0] = unit vector along the rotation axis (u);
|
|
// m_axesBottom[0] = u cross m_dVector (i.e. COM linear motion due to the rotation at the joint)
|
|
//
|
|
// for spherical: m_axesTop[0][1][2] (u1,u2,u3) form a 3x3 identity matrix (3 rotation axes)
|
|
// m_axesBottom[0][1][2] cross u1,u2,u3 (i.e. COM linear motion due to the rotation at the joint)
|
|
//
|
|
// for planar: m_axesTop[0] = unit vector along the rotation axis (u); defines the plane of motion
|
|
// m_axesTop[1][2] = zero
|
|
// m_axesBottom[0] = zero
|
|
// m_axesBottom[1][2] = unit vectors along the translational axes on that plane
|
|
btSpatialMotionVector m_axes[6];
|
|
void setAxisTop(int dof, const btVector3 &axis) { m_axes[dof].m_topVec = axis; }
|
|
void setAxisBottom(int dof, const btVector3 &axis)
|
|
{
|
|
m_axes[dof].m_bottomVec = axis;
|
|
}
|
|
void setAxisTop(int dof, const btScalar &x, const btScalar &y, const btScalar &z)
|
|
{
|
|
m_axes[dof].m_topVec.setValue(x, y, z);
|
|
}
|
|
void setAxisBottom(int dof, const btScalar &x, const btScalar &y, const btScalar &z)
|
|
{
|
|
m_axes[dof].m_bottomVec.setValue(x, y, z);
|
|
}
|
|
const btVector3 & getAxisTop(int dof) const { return m_axes[dof].m_topVec; }
|
|
const btVector3 & getAxisBottom(int dof) const { return m_axes[dof].m_bottomVec; }
|
|
|
|
int m_dofOffset, m_cfgOffset;
|
|
|
|
btQuaternion m_cachedRotParentToThis; // rotates vectors in parent frame to vectors in local frame
|
|
btVector3 m_cachedRVector; // vector from COM of parent to COM of this link, in local frame.
|
|
|
|
btVector3 m_appliedForce; // In WORLD frame
|
|
btVector3 m_appliedTorque; // In WORLD frame
|
|
|
|
btVector3 m_appliedConstraintForce; // In WORLD frame
|
|
btVector3 m_appliedConstraintTorque; // In WORLD frame
|
|
|
|
btScalar m_jointPos[7];
|
|
|
|
//m_jointTorque is the joint torque applied by the user using 'addJointTorque'.
|
|
//It gets set to zero after each internal stepSimulation call
|
|
btScalar m_jointTorque[6];
|
|
|
|
class btMultiBodyLinkCollider* m_collider;
|
|
int m_flags;
|
|
|
|
|
|
int m_dofCount, m_posVarCount; //redundant but handy
|
|
|
|
eFeatherstoneJointType m_jointType;
|
|
|
|
struct btMultiBodyJointFeedback* m_jointFeedback;
|
|
|
|
btTransform m_cachedWorldTransform;//this cache is updated when calling btMultiBody::forwardKinematics
|
|
|
|
const char* m_linkName;//m_linkName memory needs to be managed by the developer/user!
|
|
const char* m_jointName;//m_jointName memory needs to be managed by the developer/user!
|
|
const void* m_userPtr;//m_userPtr ptr needs to be managed by the developer/user!
|
|
|
|
btScalar m_jointDamping; //todo: implement this internally. It is unused for now, it is set by a URDF loader. User can apply manual damping.
|
|
btScalar m_jointFriction; //todo: implement this internally. It is unused for now, it is set by a URDF loader. User can apply manual friction using a velocity motor.
|
|
btScalar m_jointLowerLimit; //todo: implement this internally. It is unused for now, it is set by a URDF loader.
|
|
btScalar m_jointUpperLimit; //todo: implement this internally. It is unused for now, it is set by a URDF loader.
|
|
btScalar m_jointMaxForce; //todo: implement this internally. It is unused for now, it is set by a URDF loader.
|
|
btScalar m_jointMaxVelocity;//todo: implement this internally. It is unused for now, it is set by a URDF loader.
|
|
|
|
// ctor: set some sensible defaults
|
|
btMultibodyLink()
|
|
: m_mass(1),
|
|
m_parent(-1),
|
|
m_zeroRotParentToThis(0, 0, 0, 1),
|
|
m_cachedRotParentToThis(0, 0, 0, 1),
|
|
m_collider(0),
|
|
m_flags(0),
|
|
m_dofCount(0),
|
|
m_posVarCount(0),
|
|
m_jointType(btMultibodyLink::eInvalid),
|
|
m_jointFeedback(0),
|
|
m_linkName(0),
|
|
m_jointName(0),
|
|
m_userPtr(0),
|
|
m_jointDamping(0),
|
|
m_jointFriction(0),
|
|
m_jointLowerLimit(0),
|
|
m_jointUpperLimit(0),
|
|
m_jointMaxForce(0),
|
|
m_jointMaxVelocity(0)
|
|
{
|
|
|
|
m_inertiaLocal.setValue(1, 1, 1);
|
|
setAxisTop(0, 0., 0., 0.);
|
|
setAxisBottom(0, 1., 0., 0.);
|
|
m_dVector.setValue(0, 0, 0);
|
|
m_eVector.setValue(0, 0, 0);
|
|
m_cachedRVector.setValue(0, 0, 0);
|
|
m_appliedForce.setValue( 0, 0, 0);
|
|
m_appliedTorque.setValue(0, 0, 0);
|
|
//
|
|
m_jointPos[0] = m_jointPos[1] = m_jointPos[2] = m_jointPos[4] = m_jointPos[5] = m_jointPos[6] = 0.f;
|
|
m_jointPos[3] = 1.f; //"quat.w"
|
|
m_jointTorque[0] = m_jointTorque[1] = m_jointTorque[2] = m_jointTorque[3] = m_jointTorque[4] = m_jointTorque[5] = 0.f;
|
|
m_cachedWorldTransform.setIdentity();
|
|
}
|
|
|
|
// routine to update m_cachedRotParentToThis and m_cachedRVector
|
|
void updateCacheMultiDof(btScalar *pq = 0)
|
|
{
|
|
btScalar *pJointPos = (pq ? pq : &m_jointPos[0]);
|
|
|
|
switch(m_jointType)
|
|
{
|
|
case eRevolute:
|
|
{
|
|
m_cachedRotParentToThis = btQuaternion(getAxisTop(0),-pJointPos[0]) * m_zeroRotParentToThis;
|
|
m_cachedRVector = m_dVector + quatRotate(m_cachedRotParentToThis,m_eVector);
|
|
|
|
break;
|
|
}
|
|
case ePrismatic:
|
|
{
|
|
// m_cachedRotParentToThis never changes, so no need to update
|
|
m_cachedRVector = m_dVector + quatRotate(m_cachedRotParentToThis,m_eVector) + pJointPos[0] * getAxisBottom(0);
|
|
|
|
break;
|
|
}
|
|
case eSpherical:
|
|
{
|
|
m_cachedRotParentToThis = btQuaternion(pJointPos[0], pJointPos[1], pJointPos[2], -pJointPos[3]) * m_zeroRotParentToThis;
|
|
m_cachedRVector = m_dVector + quatRotate(m_cachedRotParentToThis,m_eVector);
|
|
|
|
break;
|
|
}
|
|
case ePlanar:
|
|
{
|
|
m_cachedRotParentToThis = btQuaternion(getAxisTop(0),-pJointPos[0]) * m_zeroRotParentToThis;
|
|
m_cachedRVector = quatRotate(btQuaternion(getAxisTop(0),-pJointPos[0]), pJointPos[1] * getAxisBottom(1) + pJointPos[2] * getAxisBottom(2)) + quatRotate(m_cachedRotParentToThis,m_eVector);
|
|
|
|
break;
|
|
}
|
|
case eFixed:
|
|
{
|
|
m_cachedRotParentToThis = m_zeroRotParentToThis;
|
|
m_cachedRVector = m_dVector + quatRotate(m_cachedRotParentToThis,m_eVector);
|
|
|
|
break;
|
|
}
|
|
default:
|
|
{
|
|
//invalid type
|
|
btAssert(0);
|
|
}
|
|
}
|
|
}
|
|
};
|
|
|
|
|
|
#endif //BT_MULTIBODY_LINK_H
|