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// Geometric Tools, LLC
// Copyright (c) 1998-2014
// Distributed under the Boost Software License, Version 1.0.
// http://www.boost.org/LICENSE_1_0.txt
// http://www.geometrictools.com/License/Boost/LICENSE_1_0.txt
//
// File Version: 5.0.0 (2010/01/01)
#include "PhysicsModule.h"
#include "Wm5Math.h"
#include "Wm5Memory.h"
#include "Wm5OdeRungeKutta4.h"
//----------------------------------------------------------------------------
PhysicsModule::PhysicsModule ()
:
CDivM(0.0),
GDivL(0.0),
mTime(0.0),
mDeltaTime(0.0),
mSolver(0)
{
mState[0] = 0.0;
mState[1] = 0.0;
mAux[0] = 0.0;
mAux[1] = 0.0;
}
//----------------------------------------------------------------------------
PhysicsModule::~PhysicsModule ()
{
delete0(mSolver);
}
//----------------------------------------------------------------------------
void PhysicsModule::Initialize (double time, double deltaTime, double theta,
double thetaDot)
{
mTime = time;
mDeltaTime = deltaTime;
// state variables
mState[0] = theta;
mState[1] = thetaDot;
// auxiliary variables
mAux[0] = GDivL;
mAux[1] = CDivM;
// RK4 differential equation solver. Since mSolver is a base class
// pointer, you can instead create a solver of whatever class you prefer.
delete0(mSolver);
mSolver = new0 OdeRungeKutta4d(2, mDeltaTime, OdeFunction, mAux);
}
//----------------------------------------------------------------------------
void PhysicsModule::Update ()
{
if (mSolver)
{
// Apply a single step of the ODE solver.
mSolver->Update(mTime, mState, mTime, mState);
}
}
//----------------------------------------------------------------------------
void PhysicsModule::OdeFunction (double, const double* state, void* data,
double* output)
{
double* aux = (double*)data;
double thetaDotFunction =
-(aux[0]*Mathd::Sin(state[0]) + aux[1]*state[1]);
// theta function
output[0] = state[1];
// dot(theta) function
output[1] = thetaDotFunction;
}
//----------------------------------------------------------------------------
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