3D scenes with open worlds and long rendering distances usually also contain vast terrains. Drawing ground is a very complex topic and can be performed in many different ways. Terrain in a distance cannot be too complex, as it will take up too much memory and processing power to display it. On the other hand, the area near the player must be detailed enough to look convincing and natural. That's why we need a way to lower the number of details with increasing distance or to increase the terrain's fidelity near the camera.
This is an example of how the tessellation shaders can be used to achieve high quality rendered images. For a terrain, we can use a flat plane with low number of vertices. Using tessellation shaders, we can increase the number of primitives of the ground near the camera. We can then offset generated vertices by the desired amount to increase or decrease...
