> That's the way I like it. > Project64 renders in OpenGL and Direct3D. That's why external graphics plugins are > awesome. > MAME doesn't do that.
MAME has rendered games in OpenGL and Direct3D for well over a decade, it just doesn't upscale 3D polygons the way the "enhancing" emulators do, as it's against the scope of running the games as originally intended. Someone actually added the PSEmu plugin system to a custom MAME build several years ago (but the plugins only worked with PlayStation-based arcade games as you would expect e.g. Capcom ZN, Namco System 11/12 etc.) but it violated the MAME license and therefore wasn't supported.
The problem with most plugin-based emulators is that they tend to only work with one type of hardware e.g. N64 or PSX, they are not compatible with one another (e.g. PSEmu plugins cannot be used in Project64 and vice versa) and most of them are closed source which is against both the old and current (open source) MAME license if they were to be bundled with MAME. Additionally, they are usually not cross-platform either, with most of them being Windows-only or even 32-bit only (or even x86-only, for example in the 2000s in the days of PowerPC Macs, never mind modern ARM devices).