The geometry transformation engine in the original PlayStation was called the GTE, short for Geometry Transformation Engine.
The GTE was a specialized coprocessor integrated into the PlayStation’s main processor package. It accelerated the mathematical work needed for 3D graphics, including matrix and vector calculations, coordinate transformations, perspective projection, lighting, clipping, and depth-related operations.
This division of labor was central to the PlayStation’s graphics architecture. The GTE prepared and transformed geometric data, while the separate Graphics Processing Unit, or GPU, handled rasterization and drawing. The Sound Processing Unit, or SPU, was responsible for audio, and DMA handled direct memory transfers between hardware components. These terms are therefore related to the console’s design but are not interchangeable.
The GTE used fixed-point arithmetic rather than the floating-point calculations common in modern 3D hardware. Its specialized instructions helped the 33.8688 MHz MIPS-based CPU produce the polygonal visuals seen in early PlayStation games, from texture-mapped environments to character models and racing tracks.