Two opt-in [video] keys for titles whose build carries the PGXP hooks, both
live-tunable through the TCP pgxp verb. Defaults keep today's behaviour.
pgxp_position_fallback (default true). false skips the position-cache tier
in pgxp_get_precise_vertex and stops gte.cpp filling it. At hook-build
coverage the cache only hands unrelated 3D fractions to CPU-built 2D
polygons (a HUD needle, menus). Beetle and DuckStation leave their vertex
cache off by default.
pgxp_preserve_projection (default false). true makes RTPS/RTPT shadow the
exact projection, from the unshifted MACs and a true divide
(pgxp_project_precise), instead of the GTE's integer-IR one. That removes
the residual wobble of near geometry. Guest SXY, MAC0 and FLAG are
untouched. Only sf=1 vertices with no IR, SZ3 or divide saturation qualify,
and the rest keep the IR path. The exact position can sit a little below the
guest integer or more than a pixel above it, so truncation agreement becomes
the window -4 < precise - native < 5 px, a sanity bound over the IR path's
own error (on R4 every on-screen vertex falls within -1.9 .. +2.6 px). A
packet half at or beyond the GTE saturation limit must still agree exactly.
The tolerance clamp now measures the offset both ways. [widescreen]
precise_nclip reads the same shadows, so in a title that sets both, its
branch sign follows the exact projection too.
Observability: geom_correction reports both switches, ppp_produced, and
geometry-corrected triangles split into all-precise, mixed and native. The
mixed share is the mesh-cracking exposure of G1.1.
Tests: pgxp_test (fallback off, window edges, saturation, two-sided
tolerance, the exact projection and its qualifiers, triangle census);
gte_register_access_test (RTPS/RTPT guest state equals the oracle with the
mode on, and the shadow is the exact projection); video settings test
(defaults, parsing, type check). gpu_gp0_history_guard_test's gpu.c stubs
gain pgxp_note_triangle.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Shokunin
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