How to create biomes

I am creating an 2D XNA Tile Based Platformer. I have a tile engine and a world/terrain generator. However, I am trying to create biomes or areas, For example, Desert in one part of the world, ocean on the ends, City in the middle, forests scattered around etc. I can easily make it generate them, but My problem is defining the actual areas to be generated in.

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Maybe if you post your generation code we could help you more... – Nate Jul 18 '12 at 17:36
Possible Duplicate: gamedev.stackexchange.com/questions/20551/… – DampeS8N Jul 18 '12 at 17:42
@DampeS8N, My game is a sidescroller. @_Nate Bross, My generator can generate different things by defining an area to generate – Cyral Jul 18 '12 at 17:48
possible duplicate of Random map generation – Byte56 Jul 18 '12 at 17:51
Yes, I know you're doing a side scroller, the same concepts still apply. – Byte56 Jul 18 '12 at 17:53

Without any specific knowledge of your generation algorithm, I would suggest the following.

Assuming that your world is defined in a multi-dimensional array `Tile[999,99]`

1. Decide how many "biomes" you want and of what type
2. Define the size of each biome
3. Go through your world array, and pick a start point for each biome
4. Update the world array with each biome's tile data

For example:

``````Tile[,] World = new Tile[999,99];
Tile[,] Ocean = new Tile[50,10];
// assume we want the ocean to be top left of the world, flowing off the edge
for(int i = 0; i < 50; i++)
{
for(int j = 0; j < 10; j++)
{
World[i,j] = Ocean[i,j];
}
}
``````

You could, as @Nathan suggested, use a distance from water to define which tile-set to use for each area. This could help keep your maps looking fresh and consistent, yet still be generated on-demand.

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A side scroller makes it even more simple, you just have to decide the start `x` and stop `x` for each biome. – Nate Jul 18 '12 at 18:59
I actually ended up creating a class to store the end and start of a biome, and an enum on the biome type, But based on your advise – Cyral Jul 19 '12 at 0:49
@Cyral Great! Glad it was helpful. – Nate Jul 19 '12 at 14:38

There is a great discussion of procedurally creating random biomes on a map in Polygonal Map Generation for Games by Amit Patel. His maps are arbitrary polygonal shapes, not tiles, but the same ideas should be applicable.

Briefly: generate elevation and lakes/rivers on your map using whatever method works for you, then define biomes in terms of elevation and moisture (distance to water). There is a nice table in the article that suggests different biomes for different combinations of elevation and moisture level.

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