Author: AXDOOMER

Date: December 29th, 2023

Category: GE Miscellaneous

Expansion Pak: No

The point of this patch is to help modders optimize their portals so that less is rendered by the game. The biggest performance issue on the Nintendo 64 is its fillrate, which is due to the RDRAM’s very high latency. The game’s framebuffer and Z-buffer are stored in that RAM. For the game to run at the maximum framerate it can, reads and writes to these buffers must be minimized.

The game’s code already has a few optimizations to reduce RAM writes during rendering: The game will render rooms closest to farthest (similar to the Painter's algorithm) to avoid having to update pixels which have already been drawn and their Z-Buffer value. Farther elements are more likely to have something drawn over them than closer elements. When an element is being drawn over by something else, the updated distance value of each pixel of that “something else” must be written to the Z-buffer in addition to the pixel being updated in the framebuffer.

To avoid soliciting the Z-Buffer as much as possible although the game already draws things front to back, GoldenEye uses portals. A portal is a small window to another area in the level. What’s behind that window will never be rendered if it’s out of that window’s on-screen boundaries. This enables the game engine to discard a lot of pixels which would otherwise have to be checked against their current Z-buffer value.

With the Z-buffer disabled, it’s easy to see if portals are not used optimally as some geometry might be seen being rendered above other. This patch will enable its users to have a better understanding of the effects of their portal placements. A wise usage of portals will result in less overdraw, thus a better framerate while playing the game.

The patch is compatible with mods and HLE rendering plugins like GlideN64. It will crash on LLE plugins such as ParaLLEl and on real hardware.