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DEM.cpp
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/***********************************************************************
DEM - Class to represent digital elevation models (DEMs) as float-valued
texture objects.
Copyright (c) 2013-2016 Oliver Kreylos
This file is part of the Augmented Reality Sandbox (SARndbox).
The Augmented Reality Sandbox is free software; you can redistribute it
and/or modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The Augmented Reality Sandbox is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License along
with the Augmented Reality Sandbox; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
***********************************************************************/
#include "DEM.h"
#include <IO/File.h>
#include <IO/OpenFile.h>
#include <GL/gl.h>
#include <GL/GLContextData.h>
#include <GL/Extensions/GLARBTextureFloat.h>
#include <GL/Extensions/GLARBTextureRectangle.h>
#include <GL/Extensions/GLARBTextureRg.h>
#include <GL/Extensions/GLARBShaderObjects.h>
#include <Geometry/Matrix.h>
#include <limits>
#include <stdio.h>
/******************************
Methods of class DEM::DataItem:
******************************/
DEM::DataItem::DataItem(void)
:textureObjectId(0)
{
/* Check for and initialize all required OpenGL extensions: */
GLARBTextureFloat::initExtension();
GLARBTextureRectangle::initExtension();
GLARBTextureRg::initExtension();
GLARBShaderObjects::initExtension();
/* Create the texture object: */
glGenTextures(1,&textureObjectId);
}
DEM::DataItem::~DataItem(void)
{
/* Destroy the texture object: */
glDeleteTextures(1,&textureObjectId);
}
/********************
Methods of class DEM:
********************/
void DEM::calcMatrix(void)
{
/* Convert the DEM transformation into a projective transformation matrix: */
demTransform=PTransform(transform);
PTransform::Matrix& dtm=demTransform.getMatrix();
/* Pre-multiply the projective transformation matrix with the DEM space to DEM pixel space transformation: */
PTransform dem;
dem.getMatrix()(0,0)=Scalar(demSize[0]-1)/(demBox[2]-demBox[0]);
dem.getMatrix()(0,3)=Scalar(0.5)-Scalar(demSize[0]-1)/(demBox[2]-demBox[0])*demBox[0];
dem.getMatrix()(1,1)=Scalar(demSize[1]-1)/(demBox[3]-demBox[1]);
dem.getMatrix()(1,3)=Scalar(0.5)-Scalar(demSize[1]-1)/(demBox[3]-demBox[1])*demBox[1];
dem.getMatrix()(2,2)=Scalar(1)/verticalScale;
dem.getMatrix()(2,3)=verticalScaleBase-verticalScaleBase/verticalScale;
demTransform.leftMultiply(dem);
/* Convert the full transformation to column-major OpenGL format: */
GLfloat* dtmPtr=demTransformMatrix;
for(int j=0;j<4;++j)
for(int i=0;i<4;++i,++dtmPtr)
*dtmPtr=GLfloat(dtm(i,j));
}
DEM::DEM(void)
:dem(0),
transform(OGTransform::identity),
verticalScale(1),verticalScaleBase(0)
{
demSize[0]=demSize[1]=0;
}
DEM::~DEM(void)
{
delete[] dem;
}
void DEM::initContext(GLContextData& contextData) const
{
/* Create and register a data item: */
DataItem* dataItem=new DataItem;
contextData.addDataItem(this,dataItem);
/* Upload the DEM array into the texture object: */
glBindTexture(GL_TEXTURE_RECTANGLE_ARB,dataItem->textureObjectId);
glTexParameteri(GL_TEXTURE_RECTANGLE_ARB,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_RECTANGLE_ARB,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_RECTANGLE_ARB,GL_TEXTURE_WRAP_S,GL_CLAMP);
glTexParameteri(GL_TEXTURE_RECTANGLE_ARB,GL_TEXTURE_WRAP_T,GL_CLAMP);
glTexImage2D(GL_TEXTURE_RECTANGLE_ARB,0,GL_LUMINANCE32F_ARB,demSize[0],demSize[1],0,GL_LUMINANCE,GL_FLOAT,dem);
glBindTexture(GL_TEXTURE_RECTANGLE_ARB,0);
}
void DEM::load(const char* demFileName)
{
/* Read the DEM file: */
IO::FilePtr demFile=IO::openFile(demFileName);
demFile->setEndianness(Misc::LittleEndian);
demFile->read<int>(demSize,2);
if (dem != 0)
delete[] dem;
dem=new float[demSize[1]*demSize[0]];
for(int i=0;i<4;++i)
demBox[i]=double(demFile->read<float>());
demFile->read<float>(dem,demSize[1]*demSize[0]);
/* Scale dem values so that all elevation values are between 0 and 100 */
/*
float min = calcMinElevation();
float max = calcMaxElevation();
float* demPtr = dem;
for(int i=0; i<demSize[1]*demSize[0]; i++, demPtr++)
{
*demPtr -= min;
*demPtr *= 100.0/(max-min);
}
*/
/* Update the DEM transformation: */
calcMatrix();
}
float DEM::calcAverageElevation(void) const
{
/* Sum all elevation measurements: */
double elevSum=0.0;
const float* demPtr=dem;
for(int i=demSize[1]*demSize[0];i>0;--i,++demPtr)
elevSum+=double(*demPtr);
/* Return the average elevation: */
return float(elevSum/double(demSize[1]*demSize[0]));
}
float DEM::calcMinElevation(void) const
{
/* Calculate the minimum elevation */
float min=std::numeric_limits<double>::infinity();
const float* demPtr=dem;
for(int i=demSize[1]*demSize[0];i>0;--i,++demPtr)
if (*demPtr < min) min = *demPtr;
/* Return the minimum elevation: */
return min;
}
float DEM::calcMaxElevation(void) const
{
/* Calculate the maximum elevation */
float max=-1*std::numeric_limits<double>::infinity();
const float* demPtr=dem;
for(int i=demSize[1]*demSize[0];i>0;--i,++demPtr)
if (*demPtr > max) max = *demPtr;
/* Return the maximum elevation: */
return max;
}
void DEM::setTransform(const OGTransform& newTransform,Scalar newVerticalScale,Scalar newVerticalScaleBase)
{
transform=newTransform;
verticalScale=newVerticalScale;
verticalScaleBase=newVerticalScaleBase;
/* Update the DEM transformation: */
calcMatrix();
}
void DEM::setDemVerticalScale(Scalar newVerticalScale)
{
verticalScale=newVerticalScale;
}
void DEM::setDemVerticalShift(Scalar newVerticalShift)
{
verticalShift=newVerticalShift;
}
void DEM::bindTexture(GLContextData& contextData) const
{
/* Get the context data item: */
DataItem* dataItem=contextData.retrieveDataItem<DataItem>(this);
/* Bind the DEM texture: */
glBindTexture(GL_TEXTURE_RECTANGLE_ARB,dataItem->textureObjectId);
}
void DEM::uploadDemTransform(GLint location) const
{
/* Upload the matrix to OpenGL: */
glUniformMatrix4fvARB(location,1,GL_FALSE,demTransformMatrix);
}