Update: The Canyon Mapgen Mod is a C++ based modification/fork of Minetest that brings a mapgen with plausible streams that will flow downhill to join and form bigger rivers. You can check out the code at: https://github.com/MillersMan/minetest_canyon_mapgen/tree/canyon-mapgen
Features implemented:
- A valley-like map with roughly 1000x1000 nodes (Update: spans the whole MT map now)
- Rivers with a length of more than 1000 nodes
- A groundwater-heightmap
- Groundwater is strictly flowing downhill to form rivers
- Rivers are strictly flowing downhill until they join with other rivers or leave the map
- Rivers now also affect the biomes close to them
Current limitations:
- Supporting area for each river is squared (causes straight cliffs)
- Groundwater might be above ground at the border of the supporting area
- Rivers might form loops where they almost touch an uphill part of themselves
- River beds are currently hacked in so they are always sandy and ignore the biomes
Planed features:
- Paging of generation structure (would allow rivers spanning the whole MT map with decent performance and only a few MB needed for caching, generation without cache also possible but needs a O(log n) duration instead of O(1) for generation of each chunk where n is the size of the whole MT map in one direction) (Update: is implemented now)
- Random shape for the supporting area of rivers
- Lakes and Oceans
- Waterfalls
- Rivers in caves
- Changing humidity for biomes: Currently rain is expected to be evenly distributed over the whole map
- Glaciers as springs for rivers