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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 "Wm5Memory.h"
//----------------------------------------------------------------------------
PhysicsModule::PhysicsModule (int numRows, int numCols, float step,
const Vector3f& gravity, const Vector3f& wind, float viscosity,
float amplitude)
:
MassSpringSurface3f(numRows, numCols, step),
mGravity(gravity),
mWind(wind),
mViscosity(viscosity),
mAmplitude(amplitude)
{
mDirection = mGravity.UnitCross(mWind);
mPhases = new1<float>(mNumParticles);
for (int row = 0; row < mNumRows; ++row)
{
for (int col = 0; col < mNumCols; ++col)
{
mPhases[GetIndex(row, col)] = Mathf::UnitRandom()*Mathf::PI;
}
}
}
//----------------------------------------------------------------------------
PhysicsModule::~PhysicsModule ()
{
delete1(mPhases);
}
//----------------------------------------------------------------------------
Vector3f PhysicsModule::ExternalAcceleration (int i, float time,
const Vector3f*, const Vector3f* velocities)
{
// Acceleration due to gravity, wind, and viscosity.
Vector3f acceleration = mGravity + mWind - mViscosity*velocities[i];
// Add a sinusoidal perturbation.
float amplitude = mAmplitude*Mathf::Sin(2.0f*time + mPhases[i]);
acceleration += amplitude*mDirection;
return acceleration;
}
//----------------------------------------------------------------------------
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