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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: 5.0.1 (2010/10/01)
#include "Wm5PhysicsPCH.h"
#include "Wm5MassSpringVolume.h"
#include "Wm5Memory.h"
namespace Wm5
{
//----------------------------------------------------------------------------
template <typename Real, typename TVector>
MassSpringVolume<Real,TVector>::MassSpringVolume (int numSlices, int numRows,
int numCols, Real step)
:
ParticleSystem<Real,TVector>(numSlices*numRows*numCols, step)
{
mNumSlices = numSlices;
mNumRows = numRows;
mNumCols = numCols;
mSliceQuantity = mNumRows*mNumCols;
mNumSlicesM1 = mNumSlices - 1;
mNumRowsM1 = mNumRows - 1;
mNumColsM1 = mNumCols - 1;
mPositionGrid = new1<TVector**>(mNumSlices);
mVelocityGrid = new1<TVector**>(mNumSlices);
for (int slice = 0; slice < mNumSlices; ++slice)
{
mPositionGrid[slice] = new1<TVector*>(mNumRows);
mVelocityGrid[slice] = new1<TVector*>(mNumRows);
for (int row = 0; row < mNumRows; ++row)
{
int i = mNumCols*(row + mNumRows*slice);
mPositionGrid[slice][row] = &mPositions[i];
mVelocityGrid[slice][row] = &mVelocities[i];
}
}
mConstantsS = new3<Real>(mNumCols, mNumRows, mNumSlicesM1);
mLengthsS = new3<Real>(mNumCols, mNumRows, mNumSlicesM1);
mConstantsR = new3<Real>(mNumCols, mNumRowsM1, mNumSlices);
mLengthsR = new3<Real>(mNumCols, mNumRowsM1, mNumSlices);
mConstantsC = new3<Real>(mNumColsM1, mNumRows, mNumSlices);
mLengthsC = new3<Real>(mNumColsM1, mNumRows, mNumSlices);
}
//----------------------------------------------------------------------------
template <typename Real, typename TVector>
MassSpringVolume<Real,TVector>::~MassSpringVolume ()
{
for (int slice = 0; slice < mNumSlices; ++slice)
{
delete1(mPositionGrid[slice]);
delete1(mVelocityGrid[slice]);
}
delete1(mPositionGrid);
delete1(mVelocityGrid);
delete3(mConstantsS);
delete3(mLengthsS);
delete3(mConstantsR);
delete3(mLengthsR);
delete3(mConstantsC);
delete3(mLengthsC);
}
//----------------------------------------------------------------------------
template <typename Real, typename TVector>
int MassSpringVolume<Real,TVector>::GetNumSlices () const
{
return mNumSlices;
}
//----------------------------------------------------------------------------
template <typename Real, typename TVector>
int MassSpringVolume<Real,TVector>::GetNumRows () const
{
return mNumRows;
}
//----------------------------------------------------------------------------
template <typename Real, typename TVector>
int MassSpringVolume<Real,TVector>::GetNumCols () const
{
return mNumCols;
}
//----------------------------------------------------------------------------
template <typename Real, typename TVector>
void MassSpringVolume<Real,TVector>::SetMass (int slice, int row, int col,
Real mass)
{
int i = GetIndex(slice, row, col);
ParticleSystem<Real,TVector>::SetMass(i, mass);
}
//----------------------------------------------------------------------------
template <typename Real, typename TVector>
Real MassSpringVolume<Real,TVector>::GetMass (int slice, int row, int col)
const
{
int i = GetIndex(slice, row, col);
return ParticleSystem<Real,TVector>::GetMass(i);
}
//----------------------------------------------------------------------------
template <typename Real, typename TVector>
TVector*** MassSpringVolume<Real,TVector>::Positions3D () const
{
return mPositionGrid;
}
//----------------------------------------------------------------------------
template <typename Real, typename TVector>
TVector& MassSpringVolume<Real,TVector>::Position (int slice, int row,
int col)
{
int i = GetIndex(slice, row, col);
return ParticleSystem<Real,TVector>::Position(i);
}
//----------------------------------------------------------------------------
template <typename Real, typename TVector>
TVector*** MassSpringVolume<Real,TVector>::Velocities3D () const
{
return mVelocityGrid;
}
//----------------------------------------------------------------------------
template <typename Real, typename TVector>
TVector& MassSpringVolume<Real,TVector>::Velocity (int slice, int row,
int col)
{
int i = GetIndex(slice, row, col);
return ParticleSystem<Real,TVector>::Velocity(i);
}
//----------------------------------------------------------------------------
template <typename Real, typename TVector>
Real& MassSpringVolume<Real,TVector>::ConstantS (int slice, int row, int col)
{
return mConstantsS[slice][row][col];
}
//----------------------------------------------------------------------------
template <typename Real, typename TVector>
Real& MassSpringVolume<Real,TVector>::LengthS (int slice, int row, int col)
{
return mLengthsS[slice][row][col];
}
//----------------------------------------------------------------------------
template <typename Real, typename TVector>
Real& MassSpringVolume<Real,TVector>::ConstantR (int slice, int row, int col)
{
return mConstantsR[slice][row][col];
}
//----------------------------------------------------------------------------
template <typename Real, typename TVector>
Real& MassSpringVolume<Real,TVector>::LengthR (int slice, int row, int col)
{
return mLengthsR[slice][row][col];
}
//----------------------------------------------------------------------------
template <typename Real, typename TVector>
Real& MassSpringVolume<Real,TVector>::ConstantC (int slice, int row, int col)
{
return mConstantsC[slice][row][col];
}
//----------------------------------------------------------------------------
template <typename Real, typename TVector>
Real& MassSpringVolume<Real,TVector>::LengthC (int slice, int row, int col)
{
return mLengthsC[slice][row][col];
}
//----------------------------------------------------------------------------
template <typename Real, typename TVector>
TVector MassSpringVolume<Real,TVector>::Acceleration (int i, Real time,
const TVector* positions, const TVector* velocities)
{
// Compute spring forces on position X[i]. The positions are not
// necessarily mPositions since the RK4 solver in ParticleSystem
// evaluates the acceleration function at intermediate positions. The
// face, edge, and corner points of the volume of masses must be handled
// separately since each has fewer than eight spring attached to it.
TVector acceleration = ExternalAcceleration(i, time, positions,
velocities);
TVector diff, force;
Real ratio;
int slice, row, col, prev, next;
GetCoordinates(i, slice, row, col);
if (slice > 0)
{
prev = i - mSliceQuantity; // index to previous slice-neighbor
diff = positions[prev] - positions[i];
ratio = LengthS(slice - 1, row, col)/diff.Length();
force = ConstantS(slice - 1, row, col)*((Real)1 - ratio)*diff;
acceleration += mInvMasses[i]*force;
}
if (slice < mNumSlicesM1)
{
next = i + mSliceQuantity; // index to next slice-neighbor
diff = positions[next] - positions[i];
ratio = LengthS(slice, row, col)/diff.Length();
force = ConstantS(slice, row, col)*((Real)1 - ratio)*diff;
acceleration += mInvMasses[i]*force;
}
if (row > 0)
{
prev = i - mNumCols; // index to previous row-neighbor
diff = positions[prev] - positions[i];
ratio = LengthR(slice, row - 1, col)/diff.Length();
force = ConstantR(slice, row - 1, col)*((Real)1 - ratio)*diff;
acceleration += mInvMasses[i]*force;
}
if (row < mNumRowsM1)
{
next = i + mNumCols; // index to next row-neighbor
diff = positions[next] - positions[i];
ratio = LengthR(slice, row, col)/diff.Length();
force = ConstantR(slice, row, col)*((Real)1 - ratio)*diff;
acceleration += mInvMasses[i]*force;
}
if (col > 0)
{
prev = i - 1; // index to previous col-neighbor
diff = positions[prev] - positions[i];
ratio = LengthC(slice, row, col - 1)/diff.Length();
force = ConstantC(slice, row, col - 1)*((Real)1 - ratio)*diff;
acceleration += mInvMasses[i]*force;
}
if (col < mNumColsM1)
{
next = i + 1; // index to next col-neighbor
diff = positions[next] - positions[i];
ratio = LengthC(slice, row, col)/diff.Length();
force = ConstantC(slice, row, col)*((Real)1 - ratio)*diff;
acceleration += mInvMasses[i]*force;
}
return acceleration;
}
//----------------------------------------------------------------------------
template <typename Real, typename TVector>
TVector MassSpringVolume<Real,TVector>::ExternalAcceleration (int, Real,
const TVector*, const TVector*)
{
return TVector::ZERO;
}
//----------------------------------------------------------------------------
template <typename Real, typename TVector>
int MassSpringVolume<Real,TVector>::GetIndex (int slice, int row, int col)
const
{
return col + mNumCols*(row + mNumRows*slice);
}
//----------------------------------------------------------------------------
template <typename Real, typename TVector>
void MassSpringVolume<Real,TVector>::GetCoordinates (int i, int& slice,
int& row, int& col) const
{
col = i % mNumCols;
i = (i - col)/mNumCols;
row = i % mNumRows;
slice = i / mNumRows;
}
//----------------------------------------------------------------------------
//----------------------------------------------------------------------------
// Explicit instantiation.
//----------------------------------------------------------------------------
template WM5_PHYSICS_ITEM
class MassSpringVolume<float,Vector3f>;
template WM5_PHYSICS_ITEM
class MassSpringVolume<double,Vector3d>;
//----------------------------------------------------------------------------
}
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