[osg-users] osgUtil::PlaneIntersector and Invalid Pointer and Tesselation Error

[Théo NASSOUR]

Hi,

I am using plane intersection to get the intersection of all meshes in my scene with a plane.  :

Code:

osg::ref_ptr<osgUtil::PlaneIntersector> intersector = new osgUtil::PlaneIntersector(mIntersectionPlane);

intersector->setRecordHeightsAsAttributes(true);
intersector->setPrecisionHint(osgUtil::PlaneIntersector::PrecisionHint::USE_DOUBLE_CALCULATIONS);

osgUtil::IntersectionVisitor mIntersectionVisitor; // Defined as a member usually

mIntersectionVisitor.reset();
mIntersectionVisitor.setTraversalMask(utils::MASK_SCENE_DATA);
mIntersectionVisitor.setIntersector(intersector.get());

view->getSceneData()->accept(mIntersectionVisitor);

osgUtil::PlaneIntersector::Intersections& intersections = intersector->getIntersections();




and in another function : i am computing the corresponding geode to the intersections:


Code:

inline osg::ref_ptr<osg::Geode> getSlice(const osgUtil::PlaneIntersector::Intersections & intersections)
{
osg::ref_ptr<osg::Geode> geode = new osg::Geode;
osg::ref_ptr<osg::Geometry> geometry = new osg::Geometry;
osgUtil::Tessellator tessellator;

// set the normal in the same way color.
osg::ref_ptr<osg::Vec3Array> normals = new osg::Vec3Array;
// Compute Vertices
osg::ref_ptr<osg::Vec3Array> vertices = new osg::Vec3Array;

for (const auto& intersection : intersections)
{
  for (const auto& vertex : intersection.polyline)
  {
      vertices->push_back(vertex);
      normals->push_back(osg::Vec3(0.0f, 0.0f, 1.0f));
  }
  vertices->push_back(*intersection.polyline.begin());
  normals->push_back(osg::Vec3(0.0f, 0.0f, 1.0f));
  vertices->push_back(*intersections.begin()->polyline.begin());
  normals->push_back(osg::Vec3(0.0f, 0.0f, 1.0f));
}

geometry->setVertexArray(vertices);
geometry->setNormalArray(normals, osg::Array::BIND_OVERALL);
geometry->addPrimitiveSet(new osg::DrawArrays(GL_POLYGON, 0, vertices->size()));

tessellator.setWindingType(osgUtil::Tessellator::WindingType::TESS_WINDING_NONZERO);
tessellator.setTessellationType(osgUtil::Tessellator::TESS_TYPE_GEOMETRY);
tessellator.retessellatePolygons(*geometry);

geode->addDrawable(geometry.get());
geode->getOrCreateStateSet()->setMode(GL_LIGHTING, osg::StateAttribute::ON);

return geode.get();
}




Now : 
My first Problem is : Somtimes thee last element in the NodePath of Intersections in the intersection is an invalid pointer, I don't Know why.

My Secend Problem is : Somtimes when i have meshes with Holes, the Holes are not Computed, all the mesh is filled.

Thank you!

Cheers,
Théo

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