Hi all,
currently I am writing my bachelor's thesis and I am programming in OSG.
Consequently, I am a so-called newbie.
Via 2 while-loops, which traverse the parametric representation of a unit
sphere around the origin, I receive supporting points. Singular points are
added manually.
I want to triangulate these supporting points to approximate the surface of
a unit sphere.
Therefore I pass a DelaunayTriangulator object my pointcloud (ca.
400points) and call its triangulate() method.
However, only the lower hemisphere is always triangulated. I tried to
translate the parametric representation, along the positive z-axis so that
there are no negative values for the coordinates. Even this does not change
the result.
I also tried to change the traversal of both for-loops but this did not
produce other results ,too.
At division of my pointcloud in two clouds (each ca. 400 points), one for
the lower and the other for the upper hemisphere, the triangulation works
without any problems.
Does anybody know the reason for my problem, or what am I doing wrong?
My code:
----------------------------------------------------------------------------------------------------------
geom= new Geometry();
objGeode_ = new Geode();
objGeode_->addDrawable(geom);
objGeode_->setNodeMask(objGeode_->getNodeMask() &
(~Isect::Intersection) & (~Isect::Pick));
rootNode->addChild(objGeode_);
//--------------------- array of
vertices---------------------------------
int numVertices = 20;
double firstA = 0.0;
double firstB = 0.0;
double radian = 1.0;
int counterA;
int counterB;
Vec3Array *vecTriangArray = new Vec3Array;
//singular points
vecTriangArray->push_back(Vec3(0.0, 0.0, 1.0));
vecTriangArray->push_back(Vec3(0.0, 0.0, -1.0));
//Traverse the latitude then along the meridian
counterA = 1;
firstA =(PI / numVertices)*counterA;
while(firstA < PI){
counterB = 0;
firstB = 0.0;
while(firstB < 2*PI){
double x = radian * sin(firstA) *
cos(firstB);
double y = radian * sin(firstA) *
sin(firstB);
double z = radian * cos(firstA);
vecTriangArray->push_back(Vec3(x, y,
z));
counterB++;
firstB = (2*PI / numVertices)*counterB;
}
counterA ++;
firstA =(PI / numVertices)*counterA;
}
geom -> setVertexArray(vecTriangArray);
//---------------Delaunay Triangulator-------------
DelaunayTriangulator *trig = new DelaunayTriangulator();
trig -> setInputPointArray(vecTriangArray);
//triangulate the points an add them to the primitive set
trig->triangulate();
geom->addPrimitiveSet(trig->getTriangles());
----------------------------------------------------------------------------------------------------------
Thank you,
Agnes
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