Changes

The N64 was an overly complex machine that was difficult to program for. For this reason, creating an emulator is quite difficultemulating it with a high degree of accuracy and compatibility has proven to be no simple task.===High-level vs. low-level graphics===

One of the biggest hurdles is in the road to proper N64 emulation has been accurately emulating the N64's graphics hardware, known as the Reality Display Processor, itself a part of the N64's Reality Co-Processor. The RDP is a very complex, fully -featured and very complex GPU, and emulating it at a low level has proved to be a daunting task that requires a lot of research, coding expertise, and immense amounts of system resources. For this reason, most developers have instead opted to approximate its functions using high-level emulation through various APIs such as Direct3D, OpenGL, and even Glide. While this results in much more reasonable system requirements for emulation along with high resolution graphics, this can be hit and miss, often requiring per-game tweaks and settings to prevent graphical glitches, and even then some games that implemented custom microcode (which has yet to be reverse-engineered) do not work no matter what.

For this reason, most developers have instead opted to approximate the RDP's functions using high-level emulation (HLE) through various APIs such as Direct3D, OpenGL, and even Glide. While this results in much more reasonable system requirements for emulation along with prettier, higher resolution graphics, this method can be hit and miss, often requiring per-game tweaks and settings to prevent graphical glitches on many games. Some games that implemented custom microcode (which has yet to be reverse-engineered) such as Factor 5's games do not work no matter what using high-level graphics plugins. It should also be noted that even though most games "work" through this the HLE method, it is not an accurate representation of what the N64 hardware's video output actually looked like, but rather a rough approximation by PC graphics hardware. Your mileage may vary on whether this is a good thing or not, given the N64's often blurry, low-res output.