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James Dansereau
650ac57fc6
gfx_sp_tri1's CPU-side trivial-reject AND-test trusted per-vertex outcodes (x<-w / x>w / y<-w / y>w / z>w) that are only valid half-space tests when w>0. A vertex that has crossed behind the camera plane (w<0 -- common when the camera is close to a large room-structure polygon, e.g. walls/ceiling trusses near a doorway) flips the comparison sense, so its outcode can come out wrong. When that spurious bit happens to match the other two genuinely correct vertices' bits, the AND-reduction fired and dropped the whole triangle before it ever reached OpenGL -- even though GL's own homogeneous clipper (which handles w<0 correctly) would have rendered the visible part of it. This reads exactly like D233 (indoor geometry intermittently vanishing near doors while props/furniture keep drawing): large near-camera polygons are far more likely to have a vertex cross behind the eye than small self-contained prop meshes, and the backface-cull code six lines below already special-cases this same w-sign hazard for its own cross-product sign -- the trivial-reject block above it never got the same treatment. Fix: skip the trivial-reject AND-test whenever any of the triangle's three vertices has w<0, deferring to GL's clipper instead. This can only ever send MORE triangles to the GPU than before, never fewer, so it cannot make anything newly invisible. Also investigated D234 (Dam guard towers, only the first renders) under the same M-106 hypothesis that it shares a root cause with D233/D222 -- did not find fast3d-side evidence for it; left open in findings.md with the ruled-out mechanisms and a next-step recommendation. D222 (FovScale breaks culling) is a separate, already-characterised game-logic bug in src/game/fr.c/bondview2.c, out of this fast3d-only fix's scope. Build verified green (MSYS2 mingw64 cmake+ninja, full link succeeds). Could not visually verify -- this worktree has no ROM/data and no interactive display; see docs/dev/findings.md D233 entry for the exact human verification steps (GE_PCDUMP on a doorway-heavy interior). docs/dev/findings.md: D233 (FIXED, high confidence on mechanism/unverified visually) + D234 (OPEN, not root-caused) entries added. docs/porting-notes.md: generalised the w<0 trivial-reject hazard as a recurring class for any future CPU-side "skip this triangle" heuristic. docs/dev/findings-index.csv regenerated. Claude-Session: https://claude.ai/code/session_016TaKy6AAsVUTfjkhrX6CjG
GoldenEye 007 — PC port layer
This directory contains the PC port layer: the code that lets the (unmodified) GoldenEye game sources run on a modern host instead of N64 hardware.
It mirrors the layout of the Perfect Dark PC
port, which ports the
same Rare engine family. See docs/internals.md (repo root) for the full
research write-up and phased plan.
Layout
port/
├── fast3d/ # Software RSP: interprets GBI display lists -> OpenGL
│ ├── gfx_pc.cpp # RSP interpreter (matrices, lights, tris, fog)
│ ├── gfx_opengl.cpp # OpenGL rendering backend (shaders, textures, zbuf)
│ ├── gfx_sdl2.cpp # SDL2 window-manager backend
│ ├── gfx_cc.cpp # color-combiner -> GLSL shader compiler
│ └── ...
├── include/ # port-facing headers
│ ├── audio.h config.h fs.h input.h mixer.h
│ ├── platform.h romdata.h system.h video.h utils.h
│ └── versioninfo.h.in
└── src/
├── main.c # PC entry point (replaces boot.s / init())
├── libultra.c # shims for the libultra OS API
├── video.c # SDL2 window + GL context + frame pacing
├── audio.c # SDL audio device, buffer queueing
├── mixer.c # audio mixing
├── input.c # SDL2 keyboard/mouse/gamepad -> N64 controller structs
├── fs.c # filesystem abstraction over the ROM + data dir
├── romdata.c # loads the .z64 ROM from disk, sets up segments
├── config.c # INI config (ge007.ini)
├── system.c # platform primitives (time, logging, paths)
├── crash.c # crash handler / stack traces
├── gesched.c # replacement RCP scheduler that drives the software RSP
└── utils.c
How it works (short version)
- The R4300 game code (
src/game,src) is compiled unmodified. - The RSP is emulated in software (
fast3d/): it interprets the Gfx display list the game builds and emits OpenGL calls, bypassing the RDP. - The RCP scheduler (
gesched.c) replacessrc/sched.c's hardware task submission: instead of writing RSP registers it callsgfx_run(). - libultra OS functions are shimmed in
libultra.c(single-threaded, host clock, VI/PI/SI/AI mapped onto the video/audio/fs/input layers). - Saves (Memory Pak / EEPROM) are backed by files in the data dir.
GE-specific RSP work
The PD fast3d already handles G_TRI4 (GE's 4-triangle command). The new
work for GE is:
G_SETTEX— GE's custom texture-bank command (include/gbi_extension.h,gsSPUseTexture). Must be added to the RSP interpreter + GL backend.- Verify GE's custom color-combiner modes (
G_CC_*FADE*) and render mode (G_RM_CUSTOM_AA_ZB_XLU_SURF) produce correct GLSL / GL state.
Use rsp/graphics/gmain.s (the real GE RSP ucode) as the ground truth for the
exact command encodings.
Status
Scaffolding only. The files in src/ and fast3d/ are stubs that define
the interfaces and mark the work to be done. The actual implementation is
brought in phase by phase (see docs/internals.md §8), largely by
adapting the PD port's port/ layer.