isosurfaceA new C++ library called HPMC sponsored by the Research Council of Norway enables isosurface extraction of volumetric data directly on the GPU using histogram pyramids and vertex shaders.

The library analyzes a lattice of scalar values describing a scalar field that is either stored in a Texture3D or can be accessed through an application-provided snippet of shader code. The output is a sequence of vertex positions and normals that form a triangulation of the iso-surface. HPMC provides traversal code to be included in an application vertex shader, which allows direct extraction in the vertex shader. Using the OpenGL transform feedback mechanism, the triangulation can be stored directly into a buffer object.

Requires CMake, GLEW, and a good video card, but runs on wIndows, Linux, and Mac.

via Marching Cubes using Histogram Pyramids.  (Details of the Algorithm, PDF)