I've ported this Dual Contouring implementation to C#:
http://sourceforge.net/projects/dualcontouring/
Unfortunately, I think I messed up somewhere along the way. And there's a lot of code involved, so it's hard to go through and match up the C# to the original C++ (though I will if I have to).
I know this is a long shot, but here's a screenshot of what happens when I feed in voxel data for what should be a sphere. Any ideas where I messed up?
Figured it out. The problem was my input data, not the actual dual contouring code. I was passing density values into each leaf node, rather than grid signs for the corners. I should have followed the reference in the notes linking to the documentation for PolyMender, which says this:
is a 4-bytes integer that equals 2 ^ octree_depth. The first byte of a is either 0 (denoting an intermediate node) or 1 (denoting an empty node) or 2 (denoting a leaf node). After the first byte, an intermediate node contains eight structures for its eight children; an empty node contains one byte of value 0 or 1 denoting if it is inside or outside; and a leaf node contains one byte whose eight bits correspond to the signs at its eight corners (0 for inside and 1 for outside). The order of enumeration of the eight children nodes in an intermediate nodeis the following (expressed in coordinates ): <0,0,0>,<0,0,1>,<0,1,0>,<0,1,1>,<1,0,0>,<1,0,1>,<1,1,0>,<1,1,1>. The enumeration of the eight corners in a leaf node follows the same order (e.g., the lowest bit records the sign at <0,0,0>).