StencilUtils Struct Reference

#include <StencilUtils.h>

List of all members.

Static Public Member Functions
static osg::Node *	createGeometryPass (osg::Node *geometry, int &ref_renderBin)
static osg::Node *	createMaskPass (const osg::Vec4ub &color, int &ref_renderBin)
static osg::Geode *	createVolume (Geometry *geom, double offset, double height, const FilterContext &context)

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Detailed Description

Definition at line 31 of file StencilUtils.h.

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Member Function Documentation

static osg::Node* StencilUtils::createGeometryPass	(	osg::Node *	geometry,
		int &	ref_renderBin
	)		[static]

static osg::Node* StencilUtils::createMaskPass	(	const osg::Vec4ub &	color,
		int &	ref_renderBin
	)		[static]

osg::Geode * StencilUtils::createVolume	(	Geometry *	geom,
		double	offset,
		double	height,
		const FilterContext &	context
	)		[static]

Definition at line 496 of file StencilUtils.cpp.

{
    if ( !geom ) return 0L;

    int numRings = 0;

    // start by offsetting the input data.
    if ( offset != 0.0 )
    {
        GeometryIterator i( geom );
        i.traverseMultiGeometry() = true;
        i.traversePolygonHoles() = true;
        while( i.hasMore() )
        {
            Geometry* part = i.next();
            for( osg::Vec3dArray::iterator j = part->begin(); j != part->end(); j++ )
            {
                if ( context.isGeocentric() )
                {
                    osg::Vec3d world = context.toWorld( *j );
                    // TODO: get the proper up vector; this is spherical.. or does it really matter for
                    // stencil volumes?
                    osg::Vec3d offset_vec = world;
                    offset_vec.normalize();
                    *j = context.toLocal( world + offset_vec * offset ); //(*j) += offset_vec * offset;
                }
                else
                {
                    (*j).z() += offset;
                }
            }

            // in the meantime, count the # of closed geoms. We will need to know this in 
            // order to pre-allocate the proper # of verts.
            if ( part->getType() == Geometry::TYPE_POLYGON || part->getType() == Geometry::TYPE_RING )
            {
                numRings++;
            }
        }
    }

    // now, go thru and remove any coplanar segments from the geometry. The tesselator will
    // not work include a vert connecting two colinear segments in the tesselation, and this
    // will break the stenciling logic.
#define PARALLEL_EPSILON 0.01
    GeometryIterator i( geom );
    i.traverseMultiGeometry() = true;
    i.traversePolygonHoles() = true;
    while( i.hasMore() )
    {
        Geometry* part = i.next();
        if ( part->size() >= 3 )
        {
            osg::Vec3d prevVec = part->front() - part->back();
            prevVec.normalize();

            for( osg::Vec3dArray::iterator j = part->begin(); part->size() >= 3 && j != part->end(); )
            {
                osg::Vec3d& p0 = *j;
                osg::Vec3d& p1 = j+1 != part->end() ? *(j+1) : part->front();
                osg::Vec3d vec = p1-p0; vec.normalize();

                // if the vectors are essentially parallel, remove the extraneous vertex.
                if ( (prevVec ^ vec).length() < PARALLEL_EPSILON )
                {
                    j = part->erase( j );
                    //osg::notify(osg::NOTICE) << "[osgEarth] removed colinear segment" << std::endl;
                }
                else
                {
                    ++j;
                    prevVec = vec;
                }
            }
        }
    }


    bool made_geom = true;
    const SpatialReference* srs = context.profile()->getSRS();

    // total up all the points so we can pre-allocate the vertex arrays.
    int num_cap_verts = geom->getTotalPointCount();
    int num_wall_verts = 2 * (num_cap_verts + numRings); // add in numRings b/c we need to close each wall

    osg::Geometry* walls = new osg::Geometry();
    osg::Vec3Array* verts = new osg::Vec3Array( num_wall_verts );
    walls->setVertexArray( verts );

    osg::Geometry* top_cap = new osg::Geometry();
    osg::Vec3Array* top_verts = new osg::Vec3Array( num_cap_verts );
    top_cap->setVertexArray( top_verts );

    osg::Geometry* bottom_cap = new osg::Geometry();
    osg::Vec3Array* bottom_verts = new osg::Vec3Array( num_cap_verts );
    bottom_cap->setVertexArray( bottom_verts );

    int wall_vert_ptr = 0;
    int top_vert_ptr = 0;
    int bottom_vert_ptr = 0;

    //double target_len = height;

    // now generate the extruded geometry.
    GeometryIterator k( geom );
    while( k.hasMore() )
    {
        Geometry* part = k.next();

        unsigned int wall_part_ptr = wall_vert_ptr;
        unsigned int top_part_ptr = top_vert_ptr;
        unsigned int bottom_part_ptr = bottom_vert_ptr;
        double part_len = 0.0;

        GLenum prim_type = part->getType() == Geometry::TYPE_POINTSET ? GL_LINES : GL_TRIANGLE_STRIP;

        for( osg::Vec3dArray::const_iterator m = part->begin(); m != part->end(); ++m )
        {
            osg::Vec3d extrude_vec;

            if ( srs )
            {
                osg::Vec3d m_world = context.toWorld( *m ); //*m * context.inverseReferenceFrame();
                if ( context.isGeocentric() )
                {
                    osg::Vec3d p_vec = m_world; // todo: not exactly right; spherical

                    osg::Vec3d unit_vec = p_vec; 
                    unit_vec.normalize();
                    p_vec = p_vec + unit_vec*height;

                    extrude_vec = context.toLocal( p_vec ); //p_vec * context.referenceFrame();
                }
                else
                {
                    extrude_vec.set( m_world.x(), m_world.y(), height );
                    extrude_vec = context.toLocal( extrude_vec ); //extrude_vec * context.referenceFrame();
                }
            }
            else
            {
                extrude_vec.set( m->x(), m->y(), height );
            }

            (*top_verts)[top_vert_ptr++] = extrude_vec;
            (*bottom_verts)[bottom_vert_ptr++] = *m;
             
            part_len += wall_vert_ptr > wall_part_ptr?
                (extrude_vec - (*verts)[wall_vert_ptr-2]).length() :
                0.0;

            int p;

            p = wall_vert_ptr++;
            (*verts)[p] = extrude_vec;

            p = wall_vert_ptr++;
            (*verts)[p] = *m;
        }

        // close the wall if it's a ring/poly:
        if ( part->getType() == Geometry::TYPE_RING || part->getType() == Geometry::TYPE_POLYGON )
        {
            part_len += wall_vert_ptr > wall_part_ptr?
                ((*verts)[wall_part_ptr] - (*verts)[wall_vert_ptr-2]).length() :
                0.0;

            int p;

            p = wall_vert_ptr++;
            (*verts)[p] = (*verts)[wall_part_ptr];

            p = wall_vert_ptr++;
            (*verts)[p] = (*verts)[wall_part_ptr+1];
        }

        walls->addPrimitiveSet( new osg::DrawArrays(
            prim_type,
            wall_part_ptr, wall_vert_ptr - wall_part_ptr ) );

        top_cap->addPrimitiveSet( new osg::DrawArrays(
            osg::PrimitiveSet::LINE_LOOP,
            top_part_ptr, top_vert_ptr - top_part_ptr ) );

        // reverse the bottom verts so the front face is down:
        std::reverse( bottom_verts->begin()+bottom_part_ptr, bottom_verts->begin()+bottom_vert_ptr );

        bottom_cap->addPrimitiveSet( new osg::DrawArrays(
            osg::PrimitiveSet::LINE_LOOP,
            bottom_part_ptr, bottom_vert_ptr - bottom_part_ptr ) );
    }

    // build solid surfaces for the caps:
    tessellate( top_cap );
    tessellate( bottom_cap );

    osg::Geode* geode = new osg::Geode();
    geode->addDrawable( walls );
    geode->addDrawable( top_cap );
    geode->addDrawable( bottom_cap );

    return geode;
}

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The documentation for this struct was generated from the following files:

• /home/cube/sources/osgearth/src/osgEarthDrivers/model_feature_stencil/StencilUtils.h
• /home/cube/sources/osgearth/src/osgEarthDrivers/model_feature_stencil/StencilUtils.cpp