GP

GP is an umbrella term for the graphics processing components inside the Flipper and Hollywood ASICs. It is not to be confused with GX, which is the OpenGL-like API used for interacting with these components.

GP is also present on Latte and used for Wii backwards compatibility.

The GP provides a highly flexible fixed-function GPU pipeline - the TEV's famous flexibility has led some to describe it as effectively having a rudimentary form of shader support, due to the vast number of possible configurations.

The GP, as with the rest of Flipper, was developed by a team at ArtX which included several engineers who had previously worked on the N64's graphics hardware. After ArtX was purchased by ATi, these engineers went on to lead the development of the R300 architecture.

General overview

(Based on the Wii/Wii U's 243MHz clock - GameCube uses a 162MHz clock, so performance numbers should be adjusted accordingly)

• 243MHz graphics chip
• 3MB embedded GPU memory (eDRAM)
  • 2MB dedicated to Z-buffer and framebuffer
  • 1MB texture cache
  • 24MB 1T-SRAM @ 486MHz (3.9GB/s) directly accessible for textures and other video data
• Fixed function pipeline (no support for programmable vertex or pixel shaders in hardware)
• Texture Environment Unit (TEV) - capable of combining up to 8 textures in up to 16 stages or "passes"
• ~30GB/s internal bandwidth
• ~18 million polygons/second
• 972Mpixels/sec peak pixel fillrate

Technical specifications

See Wiibrew for more information on the GP (referred to there as GX)'s components and registers.

Version Differences

The main difference between the GP components in the GameCube and the Wii/Wii U is a 1.5x increase in clock rate. There are also some minor hardware differences (errata?) which necessitated the patching of some GameCube titles by MIOS.

The version of GP found in early Flipper chips (dubbed 'HW1', or revision A) had several bugs and missing features, making it theoretically incompatible with retail games.