diff options
Diffstat (limited to 'thirdparty/bullet/BulletDynamics/Featherstone/btMultiBodyLink.h')
| -rw-r--r-- | thirdparty/bullet/BulletDynamics/Featherstone/btMultiBodyLink.h | 244 |
1 files changed, 244 insertions, 0 deletions
diff --git a/thirdparty/bullet/BulletDynamics/Featherstone/btMultiBodyLink.h b/thirdparty/bullet/BulletDynamics/Featherstone/btMultiBodyLink.h new file mode 100644 index 0000000000..01828e5843 --- /dev/null +++ b/thirdparty/bullet/BulletDynamics/Featherstone/btMultiBodyLink.h @@ -0,0 +1,244 @@ +/* +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 |