glide is a 3d graphics api made by 3dfx interactive for their "voodoo graphics" 3d accelerator cards. it was proprietary at first, then 3dfx later made it open source. it was only designed to draw graphics, mostly geometry and texture mapping, in data formats like those used in their cards. it was popular in the late 1990s because 3dfx 3d accelerator cards were widely used, but became obsolete because microsoft's direct3d got better, full opengl implementations from other graphics card vendors came out, and 3d hardware became more diverse.