C++ SPtr::setGravity方法代码示例

    /**
     * @brief Create the physical model
     *
     * @param m Mass of the particle
     * @param s Stiffness of the spring
     * @param d Damping ratio of the spring
     * @param xx0 initial position
     * @param vv0 initial velocity
     */
    void setup(
            SReal m, SReal s, SReal d,
            SReal xx0, SReal vv0
            )
    {
        mass = m;
        stiffness = s;
        damping = d;
        x0=xx0; v0=vv0;

        node = clearScene();
        node->setGravity( Vec3(0,0,0) );

        // The oscillator
        simulation::Node::SPtr oscillator = node->createChild("oscillator");

        DOF = addNew<MechanicalObject1>(oscillator,"DOF");
        DOF->resize(1);
        DOF->writePositions()[0]  = Vec1(x0);
        DOF->writeVelocities()[0] = Vec1(v0);

        UniformMass1::SPtr Mass = addNew<UniformMass1>(oscillator,"mass");
        Mass->mass.setValue( mass );

        compliance = addNew<UniformCompliance1>(oscillator,"compliance");
        compliance->isCompliance.setValue(false);
        compliance->compliance.setValue(1.0/stiffness);
        compliance->damping.setValue(damping);
    }

    /// Create the context for the scene
    void createScene(double K, double m, double l0, double rm=0, double rk=0)
    {
        // Init simulation
        sofa::simulation::setSimulation(simulation = new sofa::simulation::graph::DAGSimulation());
        root = simulation::getSimulation()->createNewGraph("root");

        // Create the scene
        root->setGravity(Coord(0,-10,0));

        // Solver
        variationalSolver = addNew<VariationalSymplecticSolver> (getRoot());
        variationalSolver->f_rayleighStiffness.setValue(rk);
        variationalSolver->f_rayleighMass.setValue(rm);
        variationalSolver->f_computeHamiltonian.setValue(1);
        variationalSolver->f_newtonError.setValue(1e-12);//1e-18
        variationalSolver->f_newtonSteps.setValue(4);//7

        CGLinearSolver::SPtr cgLinearSolver = addNew<CGLinearSolver> (getRoot());
        cgLinearSolver->f_maxIter=3000;
        cgLinearSolver->f_tolerance =1e-12;
        cgLinearSolver->f_smallDenominatorThreshold=1e-12;

        // Set initial positions and velocities of fixed point and mass
        MechanicalObject3::VecCoord xFixed(1);
        MechanicalObject3::DataTypes::set( xFixed[0], 0., 2.,0.);
        MechanicalObject3::VecDeriv vFixed(1);
        MechanicalObject3::DataTypes::set( vFixed[0], 0.,0.,0.);
        MechanicalObject3::VecCoord xMass(1);
        MechanicalObject3::DataTypes::set( xMass[0], 0., 1.,0.);
        MechanicalObject3::VecDeriv vMass(1);
        MechanicalObject3::DataTypes::set( vMass[0], 0., 0., 0.);

        // Mass spring system
        root = this-> createMassSpringSystem(
                root,   // add mass spring system to the node containing solver
                K,      // stiffness
                m,      // mass
                l0,     // spring rest length
                xFixed, // Initial position of fixed point
                vFixed, // Initial velocity of fixed point
                xMass,  // Initial position of mass
                vMass); // Initial velocity of mass
    }