Project64 already comes with a plugin that is compatible with your display card/chip
Jabo's Direct3D6 1.5.
The black grounds are a known issue when using Geforce 4MX and lower when using Detonator 50 and higher display drivers.
Prior to Det50's, several shaders were emulated in the drivers, because they are no longer emulated the game renders black ground and walls, sometimes flames are also the wrong colour.