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vtkParametricRandomHills.cxx
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vtkParametricRandomHills.cxx
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/*=========================================================================
Program: Visualization Toolkit
Module: vtkParametricRandomHills.cxx
Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
All rights reserved.
See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the above copyright notice for more information.
=========================================================================*/
#include "vtkParametricRandomHills.h"
#include "vtkObjectFactory.h"
#include "vtkMath.h"
#include "vtkDoubleArray.h"
#include <time.h>
vtkStandardNewMacro(vtkParametricRandomHills);
//----------------------------------------------------------------------------
vtkParametricRandomHills::vtkParametricRandomHills() :
NumberOfHills(30)
, HillXVariance(2.5)
, HillYVariance(2.5)
, HillAmplitude(2)
, RandomSeed(1)
, XVarianceScaleFactor(1.0/3.0)
, YVarianceScaleFactor(1.0/3.0)
, AmplitudeScaleFactor(1.0/3.0)
, AllowRandomGeneration(1)
{
// Preset triangulation parameters
this->MinimumU = -10;
this->MinimumV = -10;
this->MaximumU = 10;
this->MaximumV = 10;
this->JoinU = 0;
this->JoinV = 0;
this->TwistU = 0;
this->TwistV = 0;
this->ClockwiseOrdering = 1;
this->DerivativesAvailable = 0;
this->hillData = vtkDoubleArray::New();
GenerateTheHills();
}
//----------------------------------------------------------------------------
vtkParametricRandomHills::~vtkParametricRandomHills()
{
this->hillData->Delete();
}
//----------------------------------------------------------------------------
void vtkParametricRandomHills::InitSeed ( int randomSeed )
{
if ( randomSeed < 0 )
{
randomSeed = static_cast<int>(time( NULL ));
}
srand( static_cast<unsigned int>(randomSeed) );
}
//----------------------------------------------------------------------------
double vtkParametricRandomHills::Rand ( void )
{
return double(rand())/double(RAND_MAX);
}
//----------------------------------------------------------------------------
void vtkParametricRandomHills::Evaluate(double uvw[3], double Pt[3], double Duvw[9])
{
double u = uvw[0];
double v = uvw[1];
double *Du = Duvw;
double *Dv = Duvw + 3;
// Zero out the point and derivatives.
for ( int i = 0; i < 3; ++i )
Pt[i] = Du[i] = Dv[i] = 0;
// The point
// The height of the surface is made up from
// the contributions from all the Hills.
Pt[0] = u;
Pt[1] = this->MaximumV - v; // Texturing is oriented OK if we do this.
double hillTuple[5]; // 0: mX, 1: mY, 2: VarX, 3: VarY, 4: Amplitude
for ( int j = 0; j < NumberOfHills; ++j )
{
this->hillData->GetTuple(j,hillTuple);
double x = (u - hillTuple[0])/hillTuple[2];
double y = (v - hillTuple[1])/hillTuple[3];
Pt[2] += hillTuple[4] * exp( -(x*x+y*y) / 2.0 );
}
}
//----------------------------------------------------------------------------
double vtkParametricRandomHills::EvaluateScalar(double* vtkNotUsed(uv[3]),
double* vtkNotUsed(Pt[3]),
double* vtkNotUsed(Duv[9]))
{
return 0;
}
void vtkParametricRandomHills::GenerateTheHills( void )
{
this->hillData->Initialize();
this->hillData->SetNumberOfComponents(5);
this->hillData->SetNumberOfTuples(NumberOfHills);
double hillTuple[5]; // 0: mX, 1: mY, 2: VarX, 3: VarY, 4: Amplitude
// Generate the centers of the Hills, standard deviations and amplitudes.
if ( AllowRandomGeneration != 0 )
{
InitSeed(this->RandomSeed);
for ( int i = 0; i < this->NumberOfHills; ++ i )
{
hillTuple[0] = MinimumU + Rand() * (MaximumU - MinimumU);
hillTuple[1] = MinimumV + Rand() * (MaximumV - MinimumV);
hillTuple[2] = this->HillXVariance * Rand() + this->HillXVariance * this->XVarianceScaleFactor;
hillTuple[3] = this->HillYVariance * Rand() + this->HillYVariance * this->YVarianceScaleFactor;
hillTuple[4] = this->HillAmplitude * Rand() + this->HillAmplitude * this->AmplitudeScaleFactor;
this->hillData->SetTuple(i,hillTuple);
}
}
else
{
// Here the generation is nonrandom.
// We put hills in a regular grid over the whole surface.
double randVal = 0.1;
double gridMax = sqrt(static_cast<double>(this->NumberOfHills));
int counter = 0;
double midU = (MaximumU - MinimumU)/2.0;
double shiftU = midU / gridMax;
double midV = (MaximumV - MinimumV)/2.0;
double shiftV = midV / gridMax;
hillTuple[2] = this->HillXVariance * randVal + this->HillXVariance * this->XVarianceScaleFactor;
hillTuple[3] = this->HillYVariance * randVal + this->HillYVariance * this->YVarianceScaleFactor;
hillTuple[4] = this->HillAmplitude * randVal * 2.0 + this->HillAmplitude * this->AmplitudeScaleFactor;
for ( int i = 0; i < static_cast<int>(gridMax); ++i )
{
hillTuple[0] = MinimumU + shiftU + (i / gridMax) * (MaximumU - MinimumU);
for ( int j = 0; j < static_cast<int>(gridMax); ++j )
{
hillTuple[1] = MinimumV + shiftV + (j / gridMax) * (MaximumV - MinimumV);
this->hillData->SetTuple(counter,hillTuple);
++counter;
}
}
// If the number of hills is not a perfect square, set the amplitude contribution
// from the rest of the hills to zero.
hillTuple[4] = 0;
for ( int k = counter; k < this->NumberOfHills; ++ k )
{
hillTuple[0] = MinimumU + midU;
hillTuple[1] = MinimumV + midV;
this->hillData->SetTuple(k,hillTuple);
}
}
this->Modified();
}
//----------------------------------------------------------------------------
void vtkParametricRandomHills::PrintSelf(ostream& os, vtkIndent indent)
{
this->Superclass::PrintSelf(os,indent);
os << indent << "Hills: " << this->NumberOfHills << "\n";
os << indent << "Hill variance x-direction: " << this->HillXVariance << "\n";
os << indent << "Hill variance x-direction scaling factor: " << this->XVarianceScaleFactor << "\n";
os << indent << "Hill variance y-direction: " << this->HillYVariance << "\n";
os << indent << "Hill variance y-direction scaling factor: " << this->YVarianceScaleFactor << "\n";
os << indent << "Hill amplitude (height): " << this->HillAmplitude << "\n";
os << indent << "Amplitude scaling factor: " << this->AmplitudeScaleFactor << "\n";
os << indent << "Random number generator seed: " << this->RandomSeed << "\n";
os << indent << "Allow random generation: " << this->AllowRandomGeneration << "\n";
}