Generate next chunk with perlin noise

Question

I'm actually trying to generate a level with procedural generation using perlin noise. So one chunk has a size of 30x30, it's a float 2d array and at first I'm filling it with values between 0 and 1. Next step is to calculate 7 octaves and merge them. In the end I normalize the values. All this works quiet well if I only want to create one chunk but how can I create one more chunk beside my first so that they fit together smoothly?

Answer 1

Just set it up so your chunk has an origin, and add that to the values you're using to sample the perlin noise. i.e

void GenerateChunk(Chunk chunk, Perlin noise)
{
   for(int x = 0; x < chunk.width; x++)
   {
        for(int y = 0; y < chunk.height; y++)
        {
             chunk.value[x][y] = noise.Generate(x + chunk.origin.x, y + chunk.origin.y);
        }
   }
}

Now you've got a chunk at (0,0), one at (30, 0), one at (0, 30) and so on.

Answer 2

Expanding on the previous answer what you need is a concept of global coordinates. Every cell in the world has a globally unique coordinate which is used to generate that cell's random value. The cells themselves are stored in chunks in chunk local coordinates though, so you need a way to address each cell by chunk and offset. The spatially coherent properties of Perlin/Simplex noise then takes care of the rest.

I have some basic code examples for chunk addressing and "water-line" random generation in this blog post. Hopefully I will have posts on a more fleshed-out map generation system soon.