I noticed an insert that Activision included in the boxed version of Ritual's FPS SiN that says the following:

Commit the Ultimate Sin with the Power of 3Dfx.

Plug in a 3D accelerator with 3Dfx Interactive's Voodoo Technology and watch Sin transform from simply tempting to downright deadly.  With Advanced Multi-Texturing for wickedly fast frame rates, only 3Dfx Interactive's Voodoo Technology unleashes dynamic lighting effects and stunning transparencies for a truly unforgettable Sin.

The OpenGL version of Sin on 3Dfx.  Anything less would be unforgivable.