4 ms·
It's slightly more complicated than that. The PlayStation's geometry pipeline uses fixed-point coordinates with a decent amount of fractional precision (12 bits
by spicyjpeg 2mo ago
It's slightly more complicated than that. The PlayStation's geometry pipeline uses fixed-point coordinates with a decent amount of fractional precision (12 bits), however the GPU lacks support for subpixel rendering and operates entirely in screen space using integer X/Y pixel coordinates; all transformed vertices thus have to be rounded CPU-side before they reach the GPU. The GPU is also a 2D rasterizer only, with no perspective correction nor depth buffering, so transformed Z values are used on the CPU to sort polygons back to front (typically using hardware-assisted linked list bucket sorting) and dropped afterwards [1].
[1] https://github.com/spicyjpeg/ps1-bare-metal/blob/main/src/08_spinningCube/main.c#L252-L296 https://github.com/spicyjpeg/ps1-bare-metal/blob/main/src/08...