i have a set of points with 3d-coordinates. now i want to build a surface/mesh with triangles or rectangulars for them. are there any functions in opengl to do this job ? have i to use special algorithms ?

If all you have is a bunch of points, then there is not really any well-defined way to build a polygonal mesh through those points. You need to have some more information. If you have some way to determine interior/exterior of the object, then you could do something like constrained Delaunay triangulation of the point set and extract the surface polygons.

But you need more information than just the points, or you need to make some assumptions.

i have heard of it. the delauny triangulation is a solution for my problem. now i am looking for a “simple” code-example (eg. c++), not for a whole library or a tool.