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/*=========================================================================
Program: Visualization Toolkit
Module: vtkContextBufferId.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 "vtkContextBufferId.h"
#include "vtkIntArray.h"
#include <cassert>
#include "vtkObjectFactory.h"
#include "vtkgl.h"
vtkStandardNewMacro(vtkContextBufferId);
// ----------------------------------------------------------------------------
vtkContextBufferId::vtkContextBufferId()
{
this->IdArray=0;
}
// ----------------------------------------------------------------------------
vtkContextBufferId::~vtkContextBufferId()
{
if(this->IdArray!=0)
{
this->IdArray->Delete();
}
}
// ----------------------------------------------------------------------------
void vtkContextBufferId::Allocate()
{
assert("pre: positive_width" && this->GetWidth()>0);
assert("pre: positive_height" && this->GetHeight()>0);
vtkIdType size=this->Width*this->Height;
if(this->IdArray!=0 && this->IdArray->GetNumberOfTuples()<size)
{
this->IdArray->Delete();
this->IdArray=0;
}
if(this->IdArray==0)
{
this->IdArray=vtkIntArray::New(); // limit to 32-bit
this->IdArray->SetNumberOfComponents(1);
this->IdArray->SetNumberOfTuples(size); // allocation
}
}
// ----------------------------------------------------------------------------
bool vtkContextBufferId::IsAllocated() const
{
return this->IdArray!=0 &&
this->IdArray->GetNumberOfTuples()>=(this->Width*this->Height);
}
// ----------------------------------------------------------------------------
void vtkContextBufferId::SetValues(int srcXmin,
int srcYmin)
{
assert("pre: is_allocated" && this->IsAllocated());
GLint savedReadBuffer;
glGetIntegerv(GL_READ_BUFFER,&savedReadBuffer);
glReadBuffer(GL_BACK_LEFT);
// Expensive call here (memory allocation)
unsigned char *rgb=new unsigned char[this->Width*this->Height*3];
glPixelStorei(GL_PACK_ALIGNMENT,1);
// Expensive call here (memory transfer, blocking)
glReadPixels(srcXmin,srcYmin,this->Width,this->Height,GL_RGB,
GL_UNSIGNED_BYTE,rgb);
if(savedReadBuffer!=GL_BACK_LEFT)
{
glReadBuffer(static_cast<GLenum>(savedReadBuffer));
}
// vtkIntArray
// Interpret rgb into ids.
// We cannot just use reinterpret_cast for two reasons:
// 1. we don't know if the host system is little or big endian.
// 2. we have rgb, not rgba. if we try to grab rgba and there is not
// alpha comment, it would be set to 1.0 (255, 0xff). we don't want that.
// Expensive iteration.
vtkIdType i=0;
vtkIdType s=this->Width*this->Height;
while(i<s)
{
vtkIdType j=i*3;
int value=(static_cast<int>(rgb[j])<<16)|(static_cast<int>(rgb[j+1])<<8)
|static_cast<int>(rgb[j+2]);
this->SetValue(i,value);
++i;
}
delete[] rgb;
}
// ----------------------------------------------------------------------------
void vtkContextBufferId::SetValue(vtkIdType i,
int value)
{
assert("pre: is_allocated" && this->IsAllocated());
assert("pre: valid_i" && i>=0 && i<this->GetWidth()*this->GetHeight());
this->IdArray->SetValue(i,value);
assert("post: is_set" && this->GetValue(i)==value);
}
// ----------------------------------------------------------------------------
int vtkContextBufferId::GetValue(vtkIdType i)
{
assert("pre: is_allocated" && this->IsAllocated());
assert("pre: valid_i" && i>=0 && i<this->GetWidth()*this->GetHeight());
return this->IdArray->GetValue(i);
}
// ----------------------------------------------------------------------------
vtkIdType vtkContextBufferId::GetPickedItem(int x, int y)
{
assert("pre: is_allocated" && this->IsAllocated());
vtkIdType result=-1;
if(x<0 || x>=this->Width)
{
vtkDebugMacro(<<"x mouse position out of range: x=" << x << " (width="
<< this->Width <<")");
}
else
{
if(y<0 || y>=this->Height)
{
vtkDebugMacro(<<"y mouse position out of range: y="<< y << " (height="
<< this->Height << ")");
}
else
{
result=
static_cast<vtkIdType>(this->IdArray->GetValue(y*this->Width+x))-1;
}
}
assert("post: valid_result" && result>=-1 );
return result;
}
//-----------------------------------------------------------------------------
void vtkContextBufferId::PrintSelf(ostream &os, vtkIndent indent)
{
this->Superclass::PrintSelf(os, indent);
}
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