OpenGL Select Buffer
Provide ids of facets which intersect the viewing volume
Only perform the geometrical part of the rendering
Notes:
Thanks to its select buffer, OpenGL provides an access to a camera viewing volume content. By pushing names with the geometry we can retrieve ids of the facets inside the viewing volume.
This process only needs to perform the geometrical part of the rendering. We do not need rasterization.
Thus, this is a very fast process.
OpenGL offers two type of camera, the first one is the orthographic camera