The mapgen has 4 special features:
* River depth variation according to heat and humidity.
* Increased humidity around rivers.
* Decreased humidity with altitude.
* Decreased heat with altitude.
However until now the first 3 were all controlled by 1 flag: 'humid_rivers'.
The change splits these into 4 separate flags.
According to the mapgen flags you have set in an existing world there is a possibility of a change in the distribution of biomes, and a change to whether rivers vary in depth.
The mapgen is 'officially unstable', meaning the core devs are allowed to make changes that alter existing worlds. However this post is to let you know how you can avoid this happening.
EDIT: Please note, in this post when i write about 'altering an existing world', i do not mean that existing areas or player builds are altered. I mean that after update any newly-generated areas may be slightly different such that they do not match seamlessly with the existing areas.
In this case the only possible discontinuity is biomes having a slightly different distribution so that you may get some straight-edged biome borders between existing areas and newly-generated areas.
In your world file open the 'map_meta.txt' file and scroll down until you see the 'mgvalleys_spflags' line. For most of you it will look like this:
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mgvalleys_spflags = altitude_chill, humid_rivers
If your 'humid_rivers' flag is disabled and appears as 'nohumid_rivers' then, when you update your version of MT to a version that includes this code change, you will need to edit the flags in the file to avoid changes in your existing world. Edit the line to this:
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mgvalleys_spflags = altitude_chill, nohumid_rivers, novary_river_depth, noaltitude_dry
Code: Select all
mgvalleys_spflags = noaltitude_chill, nohumid_rivers, novary_river_depth, noaltitude_dry