Proper density functions for Voxel-based terrains?

Question

I've managed to implement the Marching Cubes algorithm in C#. Up to now I've tried the algorithm to render a sphere. That's an easy one because the density function is not very complex to code.

But now I want to get the algorithm to go further and render some interesting terrains for games. So I would need proper density functions for this task. First thing that comes to my head is a Volumetric Perlin Noise. That's ok but I am looking for a terrain without convex shapes, I mean, no caves and similar geometries by the moment.

Ok, I know that for that a simple height map can do the job, but I want a voxel-generated terrain. What type of density function o pseudocode would I need to implement them?

Answer 1

You can easily convert a heightmap into voxel terrain. Each pixel in your heightmap corresponds to a column of voxels in your voxel world. For a given pixel in the heightmap read the height. Then iterate over each voxel in the corresponding column and set it to 'solid' if it is less than your reference height or 'empty' if it is more than your reference height.

Here is some sample code using the PolyVox library.