Getting quality results on 2K by 16K heightmap

[kvark]

First results so far aren't very convincing. See https://github.com/kvark/vange-rs/pull/188 for the screenshot and the code.

Does density-mesh expect a height map at all? It has a DensityMap that I'm constructing, but I don't have a density per pixel, I have a height. So maybe I'm not using this right at all. With the settings I got so far, it takes some time to build the mesh, and it doesn't look nearly correct. It's close to random.