[5.0.0] Important info for users of Valleys mapgen

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paramat
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[5.0.0] Important info for users of Valleys mapgen

by paramat » Post

After i write this post i will be making this change to Valleys mapgen https://github.com/minetest/minetest/pull/7532

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:

Code: Select all

mgvalleys_spflags = altitude_chill, humid_rivers
These are the default flags for the mapgen. If the line looks like this then, when you update your version of MT to a version that includes this code change, the 2 new flags will be automatically added in a way that will not alter your world, so you don't need to do anything.

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:

Code: Select all

mgvalleys_spflags = altitude_chill, nohumid_rivers, novary_river_depth, noaltitude_dry
Or this:

Code: Select all

mgvalleys_spflags = noaltitude_chill, nohumid_rivers, novary_river_depth, noaltitude_dry
Depending on the setting of 'altitude_chill'.
Last edited by paramat on Sat Jul 21, 2018 22:07, edited 2 times in total.

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Wuzzy
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Re: Important info for users of Valleys mapgen

by Wuzzy » Post

Please clarify.
When I have nohumid_rivers in the config and continue anyway without fixing it, can this destroy already generated mapchunks?
Or is the worst that can happen just some weird mapchunk borders?

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paramat
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Re: Important info for users of Valleys mapgen

by paramat » Post

Good question, i was actually concerned that may be misunderstood, see the EDIT added to the first post.

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