Question Projecting a texture onto a mesh at a position on the mesh

I was looking to make a procedural damage shader similar to that used in Left4Dead2:
https://steamcdn-a.akamaihd.net/apps/valve/2010/gdc2010_vlachos_l4d2wounds.pdf

I was able to recreate the mesh clipping affect in the above document using a spheremask on the alpha of the material.

I'm having trouble figuring out how the project a texture (ie: a blood splatter) so that the texture falls over the center of where the sphere mask is.

Does anyone have a good idea on how do achieve this effect?