Hi experts,
I have 2 piece of code, use tessellaor to extrude and hole generation. Looks
the setSceneData should call after hole tessellation operation, otherwise the
viewer will draw nothing. Could you please advice on how
to setSceneData the root nodes in the begin of application, and update
the tessellated geometries in the runtime?
Code piece A runs fine.:
_viewer.setSceneData( canvas ); //canvas is a osg::Group, root node
osg::ref_ptr<osg::Vec3Array> vertices = new osg::Vec3Array;
vertices->push_back(osg::Vec3(1.0, 1.0, 0.0));
vertices->push_back(osg::Vec3(-1.0, 1.0, 0.0));
vertices->push_back(osg::Vec3(-1.0, -1.0, 0.0));
vertices->push_back(osg::Vec3(1.0, -1.0, 0.0));
osg::ref_ptr<osg::Vec3Array> newVertices = new osg::Vec3Array;
newVertices->insert( newVertices->begin(), vertices->begin(),
vertices->end() );
unsigned int numVertices = vertices->size();
osg::Vec3 offset = osg::Vec3(0.0, 0.0, 1.0) * 1.0;
for ( osg::Vec3Array::reverse_iterator ritr=vertices->rbegin();
ritr!=vertices->rend(); ++ritr )
{
newVertices->push_back( (*ritr) + offset );
}
osg::ref_ptr<osg::Geometry> extrusion = new osg::Geometry;
extrusion->setVertexArray( newVertices.get() );
extrusion->addPrimitiveSet( new osg::DrawArrays(GL_POLYGON, 0, numVertices)
);
extrusion->addPrimitiveSet( new osg::DrawArrays(GL_POLYGON, numVertices,
numVertices) );
osgUtil::Tessellator tessellator;
tessellator.setTessellationType( osgUtil::Tessellator::TESS_TYPE_GEOMETRY );
tessellator.setWindingType( osgUtil::Tessellator::TESS_WINDING_ODD );
tessellator.retessellatePolygons( *extrusion );
osg::ref_ptr<osg::DrawElementsUInt> sideIndices = new
osg::DrawElementsUInt( GL_QUAD_STRIP );
for ( unsigned int i=0; i<numVertices; ++i )
{
sideIndices->push_back( i );
sideIndices->push_back( (numVertices-1-i) + numVertices );
}
sideIndices->push_back( 0 );
sideIndices->push_back( numVertices*2 - 1 );
extrusion->addPrimitiveSet( sideIndices.get() );
osg::Geode* geode = new osg::Geode;
geode->addDrawable(extrusion);
canvas->addChild(geode);
Code piece B: runs without any geometry showed, if I put the first setSceneData
to the last line, it works.
_viewer.setSceneData( canvas );
int nstart=0; // counts vertices used for the geometry primitives
osg::ref_ptr<osg::Geometry> gtess= new osg::Geometry;
int i;
osg::ref_ptr<osg::Vec3Array> coords = new osg::Vec3Array;
double zpos = 0.0;
// front wall
static GLdouble wall[5][2] =
{ { 2200.0, 1130.0 },
{ 2600.0, 1130.0 },
{ 2600.0, 1340.0 },
{ 2400.0, 1440.0 },
{ 2200.0, 1340.0 } };
static GLdouble windows[16][2] =
{ { 2240.0, 1180.0 },
{ 2330.0, 1180.0 },
{ 2330.0, 1220.0 },
{ 2240.0, 1220.0 } };
gtess->setVertexArray(coords);
// add one large pentagon -the wall
for (i = 0; i < 5; i++) {
coords->push_back(osg::Vec3(wall[i][0],zpos,wall[i][1]));
}
osg::ref_ptr<osg::DrawArrays> contour1 = new
osg::DrawArrays(osg::PrimitiveSet::POLYGON,nstart,5);
gtess->addPrimitiveSet(contour1);nstart+=5;
// and windows
for (i = 0; i < 4; i++) {
coords->push_back(osg::Vec3(windows[i][0],zpos,windows[i][1]));
}
osg::ref_ptr<osg::DrawArrays> contour2 = new
osg::DrawArrays(osg::PrimitiveSet::QUADS,nstart,4);
gtess->addPrimitiveSet(contour2);nstart+=4;
osgUtil::Tessellator tscx; // the v1.2 multi-contour Tessellator.
tscx.setTessellationType(osgUtil::Tessellator::TESS_TYPE_GEOMETRY);
tscx.setBoundaryOnly(false);
tscx.setWindingType( osgUtil::Tessellator::TESS_WINDING_ODD);
tscx.retessellatePolygons(*gtess);
osg::Geode* geode = new osg::Geode;
geode->addDrawable(gtess);
canvas->addChild(geode);
OSG 3.2.0 OS X 10.9.4, with Qt 4.8.6 with osgQt
Thank you!
Cheers,
Yu
------------------
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=60336#60336
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