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135 lines
4.5 KiB
C++
135 lines
4.5 KiB
C++
/*
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Written by Xuchen Han <xuchenhan2015@u.northwestern.edu>
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Bullet Continuous Collision Detection and Physics Library
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Copyright (c) 2019 Google Inc. http://bulletphysics.org
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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_BACKWARD_EULER_OBJECTIVE_H
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#define BT_BACKWARD_EULER_OBJECTIVE_H
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#include "btConjugateGradient.h"
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#include "btDeformableLagrangianForce.h"
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#include "btDeformableMassSpringForce.h"
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#include "btDeformableGravityForce.h"
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#include "btDeformableCorotatedForce.h"
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#include "btDeformableLinearElasticityForce.h"
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#include "btDeformableNeoHookeanForce.h"
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#include "btDeformableContactProjection.h"
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#include "btPreconditioner.h"
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#include "btDeformableMultiBodyDynamicsWorld.h"
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#include "LinearMath/btQuickprof.h"
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class btDeformableBackwardEulerObjective
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{
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public:
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typedef btAlignedObjectArray<btVector3> TVStack;
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btScalar m_dt;
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btAlignedObjectArray<btDeformableLagrangianForce*> m_lf;
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btAlignedObjectArray<btSoftBody *>& m_softBodies;
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Preconditioner* m_preconditioner;
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btDeformableContactProjection m_projection;
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const TVStack& m_backupVelocity;
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btAlignedObjectArray<btSoftBody::Node* > m_nodes;
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bool m_implicit;
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btDeformableBackwardEulerObjective(btAlignedObjectArray<btSoftBody *>& softBodies, const TVStack& backup_v);
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virtual ~btDeformableBackwardEulerObjective();
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void initialize(){}
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// compute the rhs for CG solve, i.e, add the dt scaled implicit force to residual
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void computeResidual(btScalar dt, TVStack& residual);
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// add explicit force to the velocity
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void applyExplicitForce(TVStack& force);
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// apply force to velocity and optionally reset the force to zero
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void applyForce(TVStack& force, bool setZero);
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// compute the norm of the residual
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btScalar computeNorm(const TVStack& residual) const;
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// compute one step of the solve (there is only one solve if the system is linear)
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void computeStep(TVStack& dv, const TVStack& residual, const btScalar& dt);
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// perform A*x = b
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void multiply(const TVStack& x, TVStack& b) const;
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// set initial guess for CG solve
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void initialGuess(TVStack& dv, const TVStack& residual);
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// reset data structure and reset dt
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void reinitialize(bool nodeUpdated, btScalar dt);
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void setDt(btScalar dt);
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// add friction force to residual
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void applyDynamicFriction(TVStack& r);
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// add dv to velocity
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void updateVelocity(const TVStack& dv);
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//set constraints as projections
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void setConstraints();
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// update the projections and project the residual
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void project(TVStack& r)
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{
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BT_PROFILE("project");
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m_projection.project(r);
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}
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// perform precondition M^(-1) x = b
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void precondition(const TVStack& x, TVStack& b)
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{
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m_preconditioner->operator()(x,b);
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}
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// reindex all the vertices
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virtual void updateId()
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{
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size_t node_id = 0;
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size_t face_id = 0;
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m_nodes.clear();
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for (int i = 0; i < m_softBodies.size(); ++i)
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{
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btSoftBody* psb = m_softBodies[i];
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for (int j = 0; j < psb->m_nodes.size(); ++j)
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{
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psb->m_nodes[j].index = node_id;
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m_nodes.push_back(&psb->m_nodes[j]);
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++node_id;
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}
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for (int j = 0; j < psb->m_faces.size(); ++j)
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{
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psb->m_faces[j].m_index = face_id;
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++face_id;
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}
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}
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}
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const btAlignedObjectArray<btSoftBody::Node*>* getIndices() const
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{
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return &m_nodes;
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}
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void setImplicit(bool implicit)
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{
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m_implicit = implicit;
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}
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// Calculate the total potential energy in the system
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btScalar totalEnergy(btScalar dt);
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};
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#endif /* btBackwardEulerObjective_h */
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