Panda3D also provides classes for terrain generation. Those classes take a height field image, and generate visible geometry from the provided height field.
If you work with very large terrains, the renderer may not be able to handle such a great amount of triangles. To solve that issue, Panda3D provides LOD (Level of Detail), this means that it will generate the terrain at high quality near the focal point (which is usually the camera), but will provide lower quality terrain - that is, less triangles - because those far away parts are not as much visible as the closer parts.
Panda3D provides three classes for terrain generation and LOD handling:
The HeightfieldTesselator. This class can take a grayscale height field image and generate a terrain. It uses a linear LOD system, and, of course, because when the camera moves away from the focal point, the terrain needs to be regenerated to ‘focus’ on the new focal point. On extremely large terrains, this might lead to complications, because regenerating the entire terrain takes time, and the player might experience some lag when it is regenerated. That is why this class is not very suitable for extremely large terrains.
The GeoMipTerrain. This algorithm takes a height field and also converts it into geometry, but it splits the terrain up in smaller chunks, so when the focal point changes, not all chunks have to be regenerated. This is to prevent lagging when the focal point moves. For smaller terrains, however, you might not need such extensive terrain calculations, and use the HeightfieldTesselator instead.
ShaderTerrainMesh. This algorithm relies on a shader to deform the terrain on the GPU, making it more efficient at the expense of requiring newer hardware. A usage example for this class is included in the sample programs.
The GeoMipTerrain also provides a way to generate terrain bruteforce, that means without LOD and at full quality.
Various other terrain generators have been contributed by the community: