So I am currently working on a small Game(/engine) in OpenGL and I want to build a little world editor. Nothing too fancy: Just some functions to add objects to a scene and manipulate them (rotation, translation etc). Up to now I have everything set up for loading models into the scene and setting up simple directional- and pointlights.
But one thing has been bugging me since the start: What is an average floor / ground made out of? I would guess that, for exmaple, a grass floor is just a lot of vertices / faces with a grass texture wrapped on them. But how are those textures connected and how can you change the elevation for certain vertices to create hills?
I am essentially asking how the recommended implementation of floors is in 3D environments (preferrably OpenGL 3.3) since I can't find anything on that topic on Gergl.