The "World Cup" Lithomap

This is a set of C source tools that generate lithophanes, 3D models made from images that reveal the image when lighted from behind. The tool "lithophane" generates traditional lithophanes in STL format from images in ppm format (use ImageMagick to convert from other formats). The tool "lithocup" generates lithophanes mapped to a cylindrical surface. As an example of the latter, I have included the "World Cup" cylindrical lithophane, which reveals a map of the earth when lighted from the inside.

Update: May 10, 2014: Added "margin" option on lithocup to continue cylinder past the edges of the image. Changed lithocup so natural orientation is textured side outward, "xflip" makes it smooth side out. Orientation of cylinder is now upright with respect to the XY plane surface.

Update: May 12, 2014: Added "binary" (-b) option on lithocup and lithophane to produce (much smaller!) binary STL files instead of ASCII files.

Update: May 26, 2014: Added "margin" (-m) on lith