[1.8.9]Changing the biome in a given location

[DrasticDemise]

Hello! I am creating an item that is able to change the biome type in a given location when used, however I have run into quite a few issues and am now at a complete loss. I have a few suspicions for implementation and access, but they have all led to dead ends.

 

It appears as though (PLEASE correct me if I am wrong) biomes are stored by chunk, however there are only accessors for obtaining information about biomes in a given chunk, no mutators. The one mutator I see is "setBiomeArray" which takes a sized 256 byte array and sets the new biome array to the one given in the method call.

 

1. Does setBiomeArray allow me to change the ID and information of a given chunk to a new biome and will it then have the properties of the biome like normal?

2. If so, how do I obtain a byte Array of the given type I need? If I want to change one biome into a desert biome always, how do I get the mappings of a desert biome?

 

I have peeked a bit at 1.7.10 Blood Magic, Random Things and Witchery to attempt to learn how they modified biomes, however I was largely unsuccessful.

Any information at all would be extremely useful. Thank you!

[Elix_x]

What you said is mostly correct.

Get biome array from chunk, set biome at location to what you want and than set chunk's biome array to it.

If i remember correctly, to transform x and z to index in array, you have to do x << 4 | z, where x and z are internal chunk coordinates (global coordinates bitwise anded with 15).

[Draco18s]

If you follow the World#getBiomeForCoordinates() call stack you'll see how it gets access to the biome stored at a particular coordinate.  You'll then have to write your own method(s) to change the value.