I have created a procedural low poly rock mesh and now I would like to apply textures on it.

I have the 3D-coordinates of every vertex of the mesh but that's about it. How would I automatically generate a UV map for this mesh, since this list of vertices will change every time I generate a rock? How do I get all these faces correctly mapped in a (1,1) square?

I am working in Unity3D if that helps.

Thanks,

Alex

EDIT: Preserving the face shapes/sizes is priority! I don't want distortion at all. The texture will be generally just the same color with some darker/lighter spots so every edge could be used as a seam.