In other words, Glide64 plugins and games designed with the 3DFX's Glide API, are not able to play with DirectX or OpenGL based cards (almost every modern card, evena a crappy Geforce 2 MX400 or a FX5200). A Glide wrapper then makes possible to run Glide64 plugin or a game that uses the GLide API without using a 3DFX Voodoo card.
BTW this is kinda not the apprpiate forum for this thread