source: Swollen/swollen/watersurface.cpp @ 115

/*
  WaterSurface class

  An OpenSceneGraph viewer for pyVolution .sww files.
  copyright (C) 2004 Geoscience Australia
*/


#include <watersurface.h>
#include <osg/AlphaFunc>
#include <osg/BlendFunc>
#include <osg/PolygonMode>
#include <osg/ShapeDrawable>
#include <osg/Texture2D>
#include <osg/TexEnv>
#include <osg/TexGen>

#include <osgDB/ReadFile>
//#include <osgUtil/TriStripVisitor>

#define DEF_ALPHA_THRESHOLD 0.05


// constructor
WaterSurface::WaterSurface(SWWReader* sww)
{
   // persistent
   _sww = sww;
   _node = new osg::Geode;
   _geom = new osg::Geometry;
   _stateset = new osg::StateSet;

   // construct local scenegraph hierarchy
   _node->setName("watersurface");
   _node->addDrawable(_geom);
   _node->setStateSet(_stateset);

   _geom->setUseDisplayList( false );


   // surface starts on first timestep
   _timestep = 0;
   _dirtytimestep = true;  // will force load of watersurface

   // default is filled watersurface
   _wireframe = false;
   _dirtywireframe = true;  // will force wireframe refresh



   // environment map
   osg::Texture2D* texture = new osg::Texture2D;
   texture->setDataVariance(osg::Object::DYNAMIC);
   texture->setBorderColor(osg::Vec4(1.0f,1.0f,1.0f,0.5f));
   texture->setWrap(osg::Texture::WRAP_S, osg::Texture::REPEAT);
   std::string* envmap = new std::string( _sww->getSwollenDir() + std::string("/") + std::string("envmap.jpg") );
   texture->setImage(osgDB::readImageFile( envmap->c_str() ));
   _stateset->setTextureAttributeAndModes( 1, texture, osg::StateAttribute::ON );
   _stateset->setMode( GL_LIGHTING, osg::StateAttribute::ON );

   // surface transparency
   osg::BlendFunc* osgBlendFunc = new osg::BlendFunc();
   osgBlendFunc->setFunction(osg::BlendFunc::SRC_ALPHA, osg::BlendFunc::ONE_MINUS_SRC_ALPHA);
   _stateset->setAttribute(osgBlendFunc);
   _stateset->setMode(GL_BLEND, osg::StateAttribute::ON);
   _stateset->setRenderingHint(osg::StateSet::TRANSPARENT_BIN);

   // discard pixels with an alpha value below threshold
   osg::AlphaFunc* alphaFunc = new osg::AlphaFunc;
   alphaFunc->setFunction( osg::AlphaFunc::GREATER, DEF_ALPHA_THRESHOLD );
   _stateset->setAttributeAndModes( alphaFunc, osg::StateAttribute::ON );

   // automatically generate texture coords
   osg::TexGen* texgen = new osg::TexGen;
   texgen->setMode( osg::TexGen::SPHERE_MAP );

   osg::TexEnv* texenv = new osg::TexEnv;
   texenv->setMode( osg::TexEnv::DECAL );
   //texenv->setMode( osg::TexEnv::BLEND );
   texenv->setColor( osg::Vec4(0.6f,0.6f,0.6f,0.2f) );
   _stateset->setTextureAttributeAndModes( 1, texgen, osg::StateAttribute::ON );
   _stateset->setTextureAttribute( 1, texenv );

}



WaterSurface::~WaterSurface()
{
}



void WaterSurface::setTimeStep(unsigned int ts)
{
   if( ts != _timestep )
   {
      _timestep = ts;
      _dirtytimestep = true;
   }
}


void WaterSurface::toggleWireframe()
{
   setWireframe( _wireframe ? false : true );
}


void WaterSurface::setWireframe(bool value)
{
   if( value != _wireframe )
   {
      _wireframe = value;
      _dirtywireframe = true;
   }
}


void WaterSurface::update()
{

   if( _dirtytimestep )
   {
      // delete if exists
      if( _geom->getNumPrimitiveSets() )
         _geom->removePrimitiveSet(0);  // reference counting does actual delete

      // local reference to raw height field data
      osg::ref_ptr<osg::Vec3Array> vertices = _sww->getStageVertexArray(_timestep);
      osg::ref_ptr<osg::Vec3Array> vertexnormals = _sww->getStageVertexNormalArray();
      osg::ref_ptr<osg::Vec4Array> colors = _sww->getStageColorArray();

      // geometry
      _geom->setVertexArray( vertices.get() );
      _geom->addPrimitiveSet( _sww->getBedslopeIndexArray().get() );

      // per vertex colors (we only modulate the alpha for transparency)
      _geom->setColorArray( colors.get() );
      _geom->setColorBinding(osg::Geometry::BIND_PER_VERTEX);

      // normals
      _geom->setNormalArray( vertexnormals.get() );
      _geom->setNormalBinding(osg::Geometry::BIND_PER_VERTEX);

      // osgUtil::TriStripVisitor* optimize = new osgUtil::TriStripVisitor();
      // optimize->stripify( *_geom );

      // water surface corresponding to _timestep is now loaded ...
      _dirtytimestep = false;
   }


   if( _dirtywireframe )
   {
      osg::PolygonMode* polyModeObj = 
         dynamic_cast<osg::PolygonMode*>(_stateset->getAttribute(osg::StateAttribute::POLYGONMODE));

      if (!polyModeObj) 
      {
         polyModeObj = new osg::PolygonMode;
         _stateset->setAttribute(polyModeObj);
      }

      switch( _wireframe )
      {
         case true :
            polyModeObj->setMode(osg::PolygonMode::FRONT_AND_BACK, osg::PolygonMode::LINE);
            break;

         case false :
            polyModeObj->setMode(osg::PolygonMode::FRONT_AND_BACK, osg::PolygonMode::FILL);
            break;
      }

      // desired wireframe mode now loaded ...
      _dirtywireframe = false;

   }


}