[theevilsharpie]

I can't speak for the original GLQuake on 3dfx hardware, but on OpenGL-compatible Quake engines (which include modern Quake source ports such as Quakespasm, Ironwail, and vkQuake), bilinear texture filtering is an option that can be turned off.

I play on vkQuake with nearest-neighbor texture filtering, square particles, and the "classic" water warping effect and lighting effects, alongside 8x MSAA, 16x anisotropic filtering, high-resolution widescreen, etc. This keeps the art style consistent with the look of the original Quake, while still allowing for the benefits of hardware 3D acceleration.

[Delk]

For what it's worth, the modern source port for Descent (DXX-Rebirth) makes bilinear filtering optional, too, while using OpenGL and allowing MSAA and stuff. I played through the first two games some time ago and I also found the bilinear filtered textures worse-looking than the blocky ones.