/////////////////////////////////////////////////////////////////

/// @file MeshGrid.cpp

/// @author Chris L Baker (clb) <chris@chimail.net>

/// @date 2014.05.20

/// @brief Provide a simple interface to draw a mesh grid

///

/// @attention Copyright (C) 2014

/// @attention All rights reserved

/////////////////////////////////////////////////////////////////

#include "MeshGrid.h"

#include <osg/Geometry>

#include <osg/Geode>

#include <osg/PolygonMode>

#include <osg/Version>

namespace d3

{

/////////////////////////////////////////////////////////////////

/////////////////////////////////////////////////////////////////

osg::ref_ptr<osg::Node> get(const MeshGrid& meshGrid)

{

// build the vertex array

osg::ref_ptr<osg::Vec3Array> vertices( new osg::Vec3Array() );

vertices->reserve(meshGrid.points.size());

// Construct the color array

osg::ref_ptr<osg::Vec4Array> colors( new osg::Vec4Array() );

colors->reserve(meshGrid.points.size());

// add the points to the vetext and color array

for ( const auto& pt : meshGrid.points )

{

vertices->push_back( pt.location );

colors->push_back( pt.color );

}

// The normal array

osg::ref_ptr<osg::Vec3Array> normals( new osg::Vec3Array() );

for ( const auto& nn : meshGrid.normals )

normals->push_back(nn);

// Construct the polygon geometry

osg::ref_ptr<osg::Geometry> polygon( new osg::Geometry() );

polygon->setVertexArray( vertices.get() );

polygon->setNormalArray( normals.get() );

#if OSG_MIN_VERSION_REQUIRED(3,2,0)

polygon->setColorArray( colors.get(), osg::Array::Binding::BIND_PER_VERTEX );

#else // OSG_MIN_VERSION_REQUIRED(3,2,0)

polygon->setColorArray(colors.get());

polygon->setColorBinding(osg::Geometry::BIND_PER_VERTEX);

#endif // OSG_MIN_VERSION_REQUIRED(3,2,0)

polygon->setNormalBinding( osg::Geometry::BIND_OVERALL );

if ( not meshGrid.fill )

{

polygon->getOrCreateStateSet()->

setAttribute(new osg::PolygonMode(osg::PolygonMode::FRONT_AND_BACK,

osg::PolygonMode::LINE));

}

polygon->getOrCreateStateSet()->setMode(GL_LIGHTING, 0);

polygon->getOrCreateStateSet()->setMode(GL_BLEND, osg::StateAttribute::ON);

polygon->getOrCreateStateSet()->setRenderingHint(osg::StateSet::TRANSPARENT_BIN);

// build the thing

for ( uint ii=0 ; ii<meshGrid.points.size()-meshGrid.width-1 ; ++ii )

{

if ( not ((ii+1) % meshGrid.width) ) ++ii;

osg::ref_ptr<osg::DrawElementsUInt>

pyramidBase(new osg::DrawElementsUInt(osg::PrimitiveSet::QUADS, 0));

pyramidBase->push_back(ii);

pyramidBase->push_back(ii+1);

pyramidBase->push_back(ii+meshGrid.width+1);

pyramidBase->push_back(ii+meshGrid.width);

polygon->addPrimitiveSet(pyramidBase);

}

// create a geode for this

osg::ref_ptr<osg::Geode> geode( new osg::Geode() );

geode->addDrawable( polygon.get() );

return geode;

};

} // namespace d3