Implementating LOD

Hi all, Sorry again for having questions again. I have read some books abt LOD, however, I find sth confused to me. For the LOD, we need to prepare different level of detail for the terrain, for instance. However, I am confused how to prepare different level of deatail for the terrain. How can we instruct the openGL to do that for us?

Thx a lot~

OpenGL has no notion of level of detail for geomtery. OpenGL is only able to draw it how you sent it. It’s solely your responsibility to develop an algorithm for that.
For terrain, search the forum for ROAM. There are many pointers to already implemented algorithms.
My favorite book on LODs is
A little epic and repeating but a good survey.