# fast3d — software RSP

A C++ interpreter that consumes the `Gfx` display list the game builds each
frame and emits OpenGL calls, replacing the Nintendo 64's Reality Signal
Processor and Reality Display Processor.

## Origin and license

This code is **adapted from the [Perfect Dark PC
port](https://github.com/fgsfdsfgs/perfect_dark)** (`port/fast3d/`), which in
turn is the [Ship of Harkinian](https://github.com/HarbourMasters) /
libultraship fast3d, itself descended from
[sm64-port](https://github.com/sm64-port/sm64-port).

`LICENSE.txt` in this directory (MIT, © 2020 Emill, MaikelChan) covers that
lineage. `glad/` is generated by [glad](https://github.com/Dav1dde/glad)
(© David Herberth, MIT). GoldenEye-specific changes in this directory are
under the repository's top-level MIT license.

## Files

| File | Role |
|---|---|
| `gfx_pc.cpp` | the RSP interpreter — matrices, lights, fog, `G_TRI1`/`G_TRI4`, vtx |
| `gfx_opengl.cpp` | OpenGL backend — shaders, textures, z-buffer, framebuffers |
| `gfx_cc.cpp` | color-combiner equation -> GLSL shader |
| `gfx_sdl2.cpp` | SDL2 window-manager backend |
| `gfx_api.h` | public API (`gfx_init` / `gfx_run` / `gfx_start_frame` / ...) |
| `gbiex.h` | GoldenEye custom GBI command definitions |
| `glad/` | OpenGL loader |

## GoldenEye-specific work

The PD fast3d already handles `G_TRI4` (GoldenEye uses it too). The GE additions
are the custom color-combiner / render modes and the handling of GE's GBI
extension commands. `rsp/graphics/gmain.s` (GE's real RSP microcode, in the
repo root) is the ground truth for the exact command encodings.