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/*=========================================================================
Program: Visualization Toolkit
Module: vtkOpenGLVolumeOpacityTable.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 "vtkOpenGLVolumeOpacityTable.h"
#include "vtkObjectFactory.h"
#include "vtkOpenGLRenderWindow.h"
#include "vtkPiecewiseFunction.h"
#include "vtkTextureObject.h"
VTK_ABI_NAMESPACE_BEGIN
vtkStandardNewMacro(vtkOpenGLVolumeOpacityTable);
// Update opacity transfer function texture.
//------------------------------------------------------------------------------
void vtkOpenGLVolumeOpacityTable::InternalUpdate(
vtkObject* func, int blendMode, double sampleDistance, double unitDistance, int filterValue)
{
vtkPiecewiseFunction* scalarOpacity = vtkPiecewiseFunction::SafeDownCast(func);
if (!scalarOpacity)
{
return;
}
scalarOpacity->GetTable(this->LastRange[0], this->LastRange[1], this->TextureWidth, this->Table);
// Correct the opacity array for the spacing between the planes if we
// are using a composite blending operation
// TODO Fix this code for sample distance in three dimensions
if (this->LastBlendMode == vtkVolumeMapper::COMPOSITE_BLEND)
{
float* ptr = this->Table;
double factor = sampleDistance / unitDistance;
int i = 0;
while (i < this->TextureWidth)
{
if (*ptr > 0.0001f)
{
*ptr = static_cast<float>(1.0 - pow(1.0 - static_cast<double>(*ptr), factor));
}
++ptr;
++i;
}
}
else if (blendMode == vtkVolumeMapper::ADDITIVE_BLEND)
{
float* ptr = this->Table;
double factor = sampleDistance / unitDistance;
int i = 0;
while (i < this->TextureWidth)
{
if (*ptr > 0.0001f)
{
*ptr = static_cast<float>(static_cast<double>(*ptr) * factor);
}
++ptr;
++i;
}
}
this->TextureObject->SetWrapS(vtkTextureObject::ClampToEdge);
this->TextureObject->SetMagnificationFilter(filterValue);
this->TextureObject->SetMinificationFilter(filterValue);
this->TextureObject->Create2DFromRaw(
this->TextureWidth, 1, this->NumberOfColorComponents, VTK_FLOAT, this->Table);
}
//------------------------------------------------------------------------------
bool vtkOpenGLVolumeOpacityTable::NeedsUpdate(
vtkObject* func, double scalarRange[2], int blendMode, double sampleDistance)
{
if (this->Superclass::NeedsUpdate(func, scalarRange, blendMode, sampleDistance) ||
this->LastBlendMode != blendMode || this->LastSampleDistance != sampleDistance)
{
this->LastBlendMode = blendMode;
this->LastSampleDistance = sampleDistance;
return true;
}
return false;
}
//------------------------------------------------------------------------------
void vtkOpenGLVolumeOpacityTable::PrintSelf(ostream& os, vtkIndent indent)
{
this->Superclass::PrintSelf(os, indent);
os << indent << "Last Blend Mode: " << this->LastBlendMode << endl;
os << indent << "Last Sample Distance: " << this->LastSampleDistance << endl;
}
VTK_ABI_NAMESPACE_END
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