Each voxel datapoint in my terrain model is made up of two properties: density and material type. Each is stored as an unsigned integer value (but the density is interpreted as a decimal value between 0 and 1).

My current idea for rendering these different materials on the terrain mesh is to store eleven extra attributes in each vertex: six material values corresponding to the materials of the voxels that the vertices lie between, three decimal values that correspond to the interpolation each vertex has between each voxel, and two decimal values that are used to determine where the fragment lies on the triangle.

The material and interpolation attributes are the exact same for each vertex in the triangle. The fragment shader samples each texture that corresponds to each material and then uses the aforementioned couple of decimal values to interpolate between these samples and obtain the final textured color of the fragment.

It should work fine, but it seems like a big memory hog. I won't be able to reuse vertices in the mesh with indexing, and each vertex will have a lot of data associated with it. It also seems pretty slow. What are some ways to improve or replace this technique for drawing materials on a voxel terrain mesh?