Wangscape is an open-source program which converts rectangular terrain tiles into corner Wang tilesets with natural boundaries. Version 0.1 has just been released with Windows and Linux support, and can be downloaded here:
https://github.com/Wangscape/Wangscape/releases/tag/v0.1.
Corner Wang tilesets are described well at
cr31.co.uk. Civilization 2, Civilization 3, and Freeciv make extensive use of them.
Wangscape generates tiles using coherent noise. A noise map is made for each corner, and each pixel in the output tiles blends pixels from the input tiles according to the noise values. The noise values are made by combining
libnoise modules, to ensure that borders match and to make the output fully user-customisable. For more details, see Wangscape's
algorithm document.
Wangscape is an open source (MIT-licensed) project written in C++/Python/JSON, and contributions (bug reports, example configurations, documentation, code) are welcome. See
CONTRIBUTING.md for more information.