deformable code refactor

src/BulletSoftBody/btDeformableBackwardEulerObjective.h

@@ -0,0 +1,100 @@
+//
+//  btDeformableBackwardEulerObjective.h
+//  BulletSoftBody
+//
+//  Created by Xuchen Han on 7/1/19.
+//
+
+#ifndef BT_BACKWARD_EULER_OBJECTIVE_H
+#define BT_BACKWARD_EULER_OBJECTIVE_H
+#include <functional>
+#include "btConjugateGradient.h"
+#include "btDeformableLagrangianForce.h"
+#include "btDeformableMassSpringForce.h"
+#include "btDeformableGravityForce.h"
+#include "btDeformableContactProjection.h"
+#include "btPreconditioner.h"
+#include "btDeformableRigidDynamicsWorld.h"
+
+class btDeformableRigidDynamicsWorld;
+class btDeformableBackwardEulerObjective
+{
+public:
+    using TVStack = btAlignedObjectArray<btVector3>;
+    btScalar m_dt;
+    btDeformableRigidDynamicsWorld* m_world;
+    btAlignedObjectArray<btDeformableLagrangianForce*> m_lf;
+    btAlignedObjectArray<btSoftBody *>& m_softBodies;
+    Preconditioner* m_preconditioner;
+    btDeformableContactProjection projection;
+    const TVStack& m_backupVelocity;
+    
+    btDeformableBackwardEulerObjective(btAlignedObjectArray<btSoftBody *>& softBodies, const TVStack& backup_v);
+    
+    virtual ~btDeformableBackwardEulerObjective() {}
+    
+    void initialize(){}
+    
+    // compute the rhs for CG solve, i.e, add the dt scaled implicit force to residual
+    void computeResidual(btScalar dt, TVStack& residual) const;
+    
+    // add explicit force to the velocity
+    void applyExplicitForce(TVStack& force);
+    
+    // apply force to velocity and optionally reset the force to zero
+    void applyForce(TVStack& force, bool setZero);
+    
+    // compute the norm of the residual
+    btScalar computeNorm(const TVStack& residual) const;
+    
+    // compute one step of the solve (there is only one solve if the system is linear)
+    void computeStep(TVStack& dv, const TVStack& residual, const btScalar& dt);
+    
+    // perform A*x = b
+    void multiply(const TVStack& x, TVStack& b) const;
+    
+    // set initial guess for CG solve
+    void initialGuess(TVStack& dv, const TVStack& residual);
+    
+    // reset data structure
+    void reinitialize(bool nodeUpdated);
+    
+    void setDt(btScalar dt);
+    
+    // enforce constraints in CG solve
+    void enforceConstraint(TVStack& x)
+    {
+        projection.enforceConstraint(x);
+        updateVelocity(x);
+    }
+    
+    // add dv to velocity
+    void updateVelocity(const TVStack& dv);
+    
+    //set constraints as projections
+    void setConstraints()
+    {
+        projection.setConstraints();
+    }
+    
+    // update the projections and project the residual
+    void project(TVStack& r)
+    {
+        projection.update();
+        projection.project(r);
+    }
+    
+    // perform precondition M^(-1) x = b
+    void precondition(const TVStack& x, TVStack& b)
+    {
+        m_preconditioner->operator()(x,b);
+    }
+    
+    virtual void setWorld(btDeformableRigidDynamicsWorld* world)
+    {
+        m_world = world;
+        projection.setWorld(world);
+    }
+};
+
+#endif /* btBackwardEulerObjective_h */