7e4b1c1c8a
minor prettify of BasicDemo,RagdollDemo. require 'multiDof' argument in btMultiBody.h (not default=false)
585 lines
20 KiB
C++
585 lines
20 KiB
C++
/*
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* PURPOSE:
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* Class representing an articulated rigid body. Stores the body's
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* current state, allows forces and torques to be set, handles
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* timestepping and implements Featherstone's algorithm.
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*
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* COPYRIGHT:
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* Copyright (C) Stephen Thompson, <stephen@solarflare.org.uk>, 2011-2013
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* Portions written By Erwin Coumans: replacing Eigen math library by Bullet LinearMath and a dedicated 6x6 matrix inverse (solveImatrix)
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This software is provided 'as-is', without any express or implied warranty.
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In no event will the authors be held liable for any damages arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it freely,
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subject to the following restrictions:
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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.
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2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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*/
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#ifndef BT_MULTIBODY_H
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#define BT_MULTIBODY_H
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#include "LinearMath/btScalar.h"
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#include "LinearMath/btVector3.h"
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#include "LinearMath/btQuaternion.h"
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#include "LinearMath/btMatrix3x3.h"
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#include "LinearMath/btAlignedObjectArray.h"
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#include "btMultiBodyLink.h"
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class btMultiBodyLinkCollider;
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class btMultiBody
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{
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public:
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BT_DECLARE_ALIGNED_ALLOCATOR();
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//
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// initialization
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//
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btMultiBody(int n_links, // NOT including the base
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btScalar mass, // mass of base
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const btVector3 &inertia, // inertia of base, in base frame; assumed diagonal
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bool fixedBase, // whether the base is fixed (true) or can move (false)
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bool canSleep,
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bool multiDof
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);
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~btMultiBody();
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void setupPrismatic(int i, // 0 to num_links-1
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btScalar mass,
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const btVector3 &inertia, // in my frame; assumed diagonal
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int parent,
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const btQuaternion &rotParentToThis, // rotate points in parent frame to my frame.
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const btVector3 &jointAxis, // in my frame
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const btVector3 &parentComToThisComOffset, // vector from parent COM to my COM, in my frame, when q = 0.
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bool disableParentCollision=false
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);
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void setupRevolute(int i, // 0 to num_links-1
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btScalar mass,
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const btVector3 &inertia,
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int parent,
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const btQuaternion &rotParentToThis, // rotate points in parent frame to this frame, when q = 0
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const btVector3 &jointAxis, // in my frame
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const btVector3 &parentComToThisPivotOffset, // vector from parent COM to joint axis, in PARENT frame
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const btVector3 &thisPivotToThisComOffset, // vector from joint axis to my COM, in MY frame
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bool disableParentCollision=false);
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void setupSpherical(int i, // 0 to num_links-1
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btScalar mass,
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const btVector3 &inertia,
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int parent,
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const btQuaternion &rotParentToThis, // rotate points in parent frame to this frame, when q = 0
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const btVector3 &parentComToThisPivotOffset, // vector from parent COM to joint axis, in PARENT frame
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const btVector3 &thisPivotToThisComOffset, // vector from joint axis to my COM, in MY frame
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bool disableParentCollision=false);
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#ifdef BT_MULTIBODYLINK_INCLUDE_PLANAR_JOINTS
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void setupPlanar(int i, // 0 to num_links-1
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btScalar mass,
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const btVector3 &inertia,
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int parent,
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const btQuaternion &rotParentToThis, // rotate points in parent frame to this frame, when q = 0
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const btVector3 &rotationAxis,
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const btVector3 &parentComToThisComOffset, // vector from parent COM to this COM, in PARENT frame
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bool disableParentCollision=false);
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#endif
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const btMultibodyLink& getLink(int index) const
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{
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return m_links[index];
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}
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btMultibodyLink& getLink(int index)
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{
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return m_links[index];
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}
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void setBaseCollider(btMultiBodyLinkCollider* collider)//collider can be NULL to disable collision for the base
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{
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m_baseCollider = collider;
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}
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const btMultiBodyLinkCollider* getBaseCollider() const
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{
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return m_baseCollider;
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}
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btMultiBodyLinkCollider* getBaseCollider()
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{
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return m_baseCollider;
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}
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//
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// get parent
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// input: link num from 0 to num_links-1
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// output: link num from 0 to num_links-1, OR -1 to mean the base.
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//
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int getParent(int link_num) const;
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//
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// get number of m_links, masses, moments of inertia
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//
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int getNumLinks() const { return m_links.size(); }
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int getNumDofs() const { return m_dofCount; }
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int getNumPosVars() const { return m_posVarCnt; }
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btScalar getBaseMass() const { return m_baseMass; }
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const btVector3 & getBaseInertia() const { return m_baseInertia; }
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btScalar getLinkMass(int i) const;
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const btVector3 & getLinkInertia(int i) const;
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//
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// change mass (incomplete: can only change base mass and inertia at present)
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//
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void setBaseMass(btScalar mass) { m_baseMass = mass; }
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void setBaseInertia(const btVector3 &inertia) { m_baseInertia = inertia; }
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//
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// get/set pos/vel/rot/omega for the base link
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//
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const btVector3 & getBasePos() const { return m_basePos; } // in world frame
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const btVector3 getBaseVel() const
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{
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return btVector3(m_realBuf[3],m_realBuf[4],m_realBuf[5]);
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} // in world frame
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const btQuaternion & getWorldToBaseRot() const
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{
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return m_baseQuat;
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} // rotates world vectors into base frame
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btVector3 getBaseOmega() const { return btVector3(m_realBuf[0],m_realBuf[1],m_realBuf[2]); } // in world frame
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void setBasePos(const btVector3 &pos)
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{
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m_basePos = pos;
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}
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void setBaseVel(const btVector3 &vel)
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{
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m_realBuf[3]=vel[0]; m_realBuf[4]=vel[1]; m_realBuf[5]=vel[2];
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}
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void setWorldToBaseRot(const btQuaternion &rot)
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{
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m_baseQuat = rot; //m_baseQuat asumed to ba alias!?
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}
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void setBaseOmega(const btVector3 &omega)
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{
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m_realBuf[0]=omega[0];
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m_realBuf[1]=omega[1];
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m_realBuf[2]=omega[2];
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}
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//
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// get/set pos/vel for child m_links (i = 0 to num_links-1)
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//
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btScalar getJointPos(int i) const;
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btScalar getJointVel(int i) const;
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btScalar * getJointVelMultiDof(int i);
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btScalar * getJointPosMultiDof(int i);
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void setJointPos(int i, btScalar q);
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void setJointVel(int i, btScalar qdot);
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void setJointPosMultiDof(int i, btScalar *q);
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void setJointVelMultiDof(int i, btScalar *qdot);
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//
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// direct access to velocities as a vector of 6 + num_links elements.
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// (omega first, then v, then joint velocities.)
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//
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const btScalar * getVelocityVector() const
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{
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return &m_realBuf[0];
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}
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/* btScalar * getVelocityVector()
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{
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return &real_buf[0];
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}
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*/
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//
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// get the frames of reference (positions and orientations) of the child m_links
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// (i = 0 to num_links-1)
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//
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const btVector3 & getRVector(int i) const; // vector from COM(parent(i)) to COM(i), in frame i's coords
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const btQuaternion & getParentToLocalRot(int i) const; // rotates vectors in frame parent(i) to vectors in frame i.
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//
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// transform vectors in local frame of link i to world frame (or vice versa)
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//
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btVector3 localPosToWorld(int i, const btVector3 &vec) const;
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btVector3 localDirToWorld(int i, const btVector3 &vec) const;
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btVector3 worldPosToLocal(int i, const btVector3 &vec) const;
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btVector3 worldDirToLocal(int i, const btVector3 &vec) const;
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//
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// calculate kinetic energy and angular momentum
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// useful for debugging.
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//
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btScalar getKineticEnergy() const;
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btVector3 getAngularMomentum() const;
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//
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// set external forces and torques. Note all external forces/torques are given in the WORLD frame.
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//
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void clearForcesAndTorques();
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void clearVelocities();
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void addBaseForce(const btVector3 &f)
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{
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m_baseForce += f;
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}
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void addBaseTorque(const btVector3 &t) { m_baseTorque += t; }
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void addLinkForce(int i, const btVector3 &f);
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void addLinkTorque(int i, const btVector3 &t);
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void addJointTorque(int i, btScalar Q);
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void addJointTorqueMultiDof(int i, int dof, btScalar Q);
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void addJointTorqueMultiDof(int i, const btScalar *Q);
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const btVector3 & getBaseForce() const { return m_baseForce; }
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const btVector3 & getBaseTorque() const { return m_baseTorque; }
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const btVector3 & getLinkForce(int i) const;
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const btVector3 & getLinkTorque(int i) const;
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btScalar getJointTorque(int i) const;
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btScalar * getJointTorqueMultiDof(int i);
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//
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// dynamics routines.
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//
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// timestep the velocities (given the external forces/torques set using addBaseForce etc).
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// also sets up caches for calcAccelerationDeltas.
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//
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// Note: the caller must provide three vectors which are used as
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// temporary scratch space. The idea here is to reduce dynamic
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// memory allocation: the same scratch vectors can be re-used
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// again and again for different Multibodies, instead of each
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// btMultiBody allocating (and then deallocating) their own
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// individual scratch buffers. This gives a considerable speed
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// improvement, at least on Windows (where dynamic memory
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// allocation appears to be fairly slow).
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//
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void stepVelocities(btScalar dt,
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btAlignedObjectArray<btScalar> &scratch_r,
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btAlignedObjectArray<btVector3> &scratch_v,
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btAlignedObjectArray<btMatrix3x3> &scratch_m);
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void stepVelocitiesMultiDof(btScalar dt,
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btAlignedObjectArray<btScalar> &scratch_r,
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btAlignedObjectArray<btVector3> &scratch_v,
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btAlignedObjectArray<btMatrix3x3> &scratch_m);
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// calcAccelerationDeltas
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// input: force vector (in same format as jacobian, i.e.:
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// 3 torque values, 3 force values, num_links joint torque values)
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// output: 3 omegadot values, 3 vdot values, num_links q_double_dot values
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// (existing contents of output array are replaced)
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// stepVelocities must have been called first.
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void calcAccelerationDeltas(const btScalar *force, btScalar *output,
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btAlignedObjectArray<btScalar> &scratch_r,
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btAlignedObjectArray<btVector3> &scratch_v) const;
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void calcAccelerationDeltasMultiDof(const btScalar *force, btScalar *output,
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btAlignedObjectArray<btScalar> &scratch_r,
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btAlignedObjectArray<btVector3> &scratch_v) const;
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// apply a delta-vee directly. used in sequential impulses code.
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void applyDeltaVee(const btScalar * delta_vee)
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{
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for (int i = 0; i < 6 + getNumLinks(); ++i)
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{
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m_realBuf[i] += delta_vee[i];
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}
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}
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void applyDeltaVee(const btScalar * delta_vee, btScalar multiplier)
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{
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btScalar sum = 0;
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for (int i = 0; i < 6 + getNumLinks(); ++i)
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{
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sum += delta_vee[i]*multiplier*delta_vee[i]*multiplier;
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}
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btScalar l = btSqrt(sum);
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/*
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static btScalar maxl = -1e30f;
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if (l>maxl)
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{
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maxl=l;
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// printf("maxl=%f\n",maxl);
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}
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*/
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if (l>m_maxAppliedImpulse)
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{
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// printf("exceeds 100: l=%f\n",maxl);
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multiplier *= m_maxAppliedImpulse/l;
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}
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for (int i = 0; i < 6 + getNumLinks(); ++i)
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{
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sum += delta_vee[i]*multiplier*delta_vee[i]*multiplier;
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m_realBuf[i] += delta_vee[i] * multiplier;
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}
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}
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void applyDeltaVeeMultiDof(const btScalar * delta_vee, btScalar multiplier)
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{
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//for (int dof = 0; dof < 6 + getNumDofs(); ++dof)
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// printf("%.4f ", delta_vee[dof]*multiplier);
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//printf("\n");
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//btScalar sum = 0;
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//for (int dof = 0; dof < 6 + getNumDofs(); ++dof)
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//{
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// sum += delta_vee[dof]*multiplier*delta_vee[dof]*multiplier;
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//}
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//btScalar l = btSqrt(sum);
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//if (l>m_maxAppliedImpulse)
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//{
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// multiplier *= m_maxAppliedImpulse/l;
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//}
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for (int dof = 0; dof < 6 + getNumDofs(); ++dof)
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{
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m_realBuf[dof] += delta_vee[dof] * multiplier;
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}
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}
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// timestep the positions (given current velocities).
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void stepPositions(btScalar dt);
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void stepPositionsMultiDof(btScalar dt, btScalar *pq = 0, btScalar *pqd = 0);
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//
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// contacts
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//
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// This routine fills out a contact constraint jacobian for this body.
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// the 'normal' supplied must be -n for body1 or +n for body2 of the contact.
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// 'normal' & 'contact_point' are both given in world coordinates.
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void fillContactJacobian(int link,
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const btVector3 &contact_point,
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const btVector3 &normal,
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btScalar *jac,
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btAlignedObjectArray<btScalar> &scratch_r,
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btAlignedObjectArray<btVector3> &scratch_v,
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btAlignedObjectArray<btMatrix3x3> &scratch_m) const;
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//multidof version of fillContactJacobian
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void fillContactJacobianMultiDof(int link,
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const btVector3 &contact_point,
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const btVector3 &normal,
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btScalar *jac,
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btAlignedObjectArray<btScalar> &scratch_r,
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btAlignedObjectArray<btVector3> &scratch_v,
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btAlignedObjectArray<btMatrix3x3> &scratch_m) const { filConstraintJacobianMultiDof(link, contact_point, btVector3(0, 0, 0), normal, jac, scratch_r, scratch_v, scratch_m); }
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//a more general version of fillContactJacobianMultiDof which does not assume..
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//.. that the constraint in question is contact or, to be more precise, constrains linear velocity only
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void filConstraintJacobianMultiDof(int link,
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const btVector3 &contact_point,
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const btVector3 &normal_ang,
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const btVector3 &normal_lin,
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btScalar *jac,
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btAlignedObjectArray<btScalar> &scratch_r,
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btAlignedObjectArray<btVector3> &scratch_v,
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btAlignedObjectArray<btMatrix3x3> &scratch_m) const;
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//
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// sleeping
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//
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void setCanSleep(bool canSleep)
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{
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m_canSleep = canSleep;
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}
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bool isAwake() const { return m_awake; }
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void wakeUp();
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void goToSleep();
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void checkMotionAndSleepIfRequired(btScalar timestep);
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bool hasFixedBase() const
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{
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return m_fixedBase;
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}
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int getCompanionId() const
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{
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return m_companionId;
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}
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void setCompanionId(int id)
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{
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//printf("for %p setCompanionId(%d)\n",this, id);
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m_companionId = id;
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}
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void setNumLinks(int numLinks)//careful: when changing the number of m_links, make sure to re-initialize or update existing m_links
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{
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m_links.resize(numLinks);
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}
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btScalar getLinearDamping() const
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{
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return m_linearDamping;
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}
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void setLinearDamping( btScalar damp)
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{
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m_linearDamping = damp;
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}
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btScalar getAngularDamping() const
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{
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return m_angularDamping;
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}
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void setAngularDamping( btScalar damp)
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{
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m_angularDamping = damp;
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}
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bool getUseGyroTerm() const
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{
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return m_useGyroTerm;
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}
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void setUseGyroTerm(bool useGyro)
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{
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m_useGyroTerm = useGyro;
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}
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btScalar getMaxAppliedImpulse() const
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{
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return m_maxAppliedImpulse;
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}
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void setMaxAppliedImpulse(btScalar maxImp)
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{
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m_maxAppliedImpulse = maxImp;
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}
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void setHasSelfCollision(bool hasSelfCollision)
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{
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m_hasSelfCollision = hasSelfCollision;
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}
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bool hasSelfCollision() const
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{
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return m_hasSelfCollision;
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}
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bool isMultiDof() { return m_isMultiDof; }
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void finalizeMultiDof();
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void useRK4Integration(bool use) { m_useRK4 = use; }
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bool isUsingRK4Integration() const { return m_useRK4; }
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void useGlobalVelocities(bool use) { m_useGlobalVelocities = use; }
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bool isUsingGlobalVelocities() const { return m_useGlobalVelocities; }
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bool __posUpdated;
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private:
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btMultiBody(const btMultiBody &); // not implemented
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void operator=(const btMultiBody &); // not implemented
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void compTreeLinkVelocities(btVector3 *omega, btVector3 *vel) const;
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void solveImatrix(const btVector3& rhs_top, const btVector3& rhs_bot, float result[6]) const;
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#ifdef TEST_SPATIAL_ALGEBRA_LAYER
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void solveImatrix(const btSpatialForceVector &rhs, btSpatialMotionVector &result) const;
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#endif
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void updateLinksDofOffsets()
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{
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int dofOffset = 0, cfgOffset = 0;
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for(int bidx = 0; bidx < m_links.size(); ++bidx)
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{
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m_links[bidx].m_dofOffset = dofOffset; m_links[bidx].m_cfgOffset = cfgOffset;
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dofOffset += m_links[bidx].m_dofCount; cfgOffset += m_links[bidx].m_posVarCount;
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}
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}
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void mulMatrix(btScalar *pA, btScalar *pB, int rowsA, int colsA, int rowsB, int colsB, btScalar *pC) const;
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private:
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btMultiBodyLinkCollider* m_baseCollider;//can be NULL
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btVector3 m_basePos; // position of COM of base (world frame)
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btQuaternion m_baseQuat; // rotates world points into base frame
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btScalar m_baseMass; // mass of the base
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btVector3 m_baseInertia; // inertia of the base (in local frame; diagonal)
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btVector3 m_baseForce; // external force applied to base. World frame.
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btVector3 m_baseTorque; // external torque applied to base. World frame.
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btAlignedObjectArray<btMultibodyLink> m_links; // array of m_links, excluding the base. index from 0 to num_links-1.
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btAlignedObjectArray<btMultiBodyLinkCollider*> m_colliders;
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int m_dofCount, m_posVarCnt;
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bool m_useRK4, m_useGlobalVelocities;
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//
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// realBuf:
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// offset size array
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// 0 6 + num_links v (base_omega; base_vel; joint_vels) MULTIDOF [sysdof x sysdof for D matrices (TOO MUCH!) + pos_delta which is sys-cfg sized]
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// 6+num_links num_links D
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//
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// vectorBuf:
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// offset size array
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// 0 num_links h_top
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// num_links num_links h_bottom
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//
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// matrixBuf:
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// offset size array
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// 0 num_links+1 rot_from_parent
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//
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btAlignedObjectArray<btScalar> m_realBuf;
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btAlignedObjectArray<btVector3> m_vectorBuf;
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btAlignedObjectArray<btMatrix3x3> m_matrixBuf;
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//std::auto_ptr<Eigen::LU<Eigen::Matrix<btScalar, 6, 6> > > cached_imatrix_lu;
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btMatrix3x3 m_cachedInertiaTopLeft;
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btMatrix3x3 m_cachedInertiaTopRight;
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btMatrix3x3 m_cachedInertiaLowerLeft;
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btMatrix3x3 m_cachedInertiaLowerRight;
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bool m_fixedBase;
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// Sleep parameters.
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bool m_awake;
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bool m_canSleep;
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btScalar m_sleepTimer;
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int m_companionId;
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btScalar m_linearDamping;
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btScalar m_angularDamping;
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bool m_useGyroTerm;
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btScalar m_maxAppliedImpulse;
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bool m_hasSelfCollision;
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bool m_isMultiDof;
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};
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#endif
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