nx_frame_sanity.nx

nx_frame_sanity.nx -- EXPERIENTIAL frame verifier: mechanizes the eyeball for rendered RGB frames. WHY: three Gx framing bugs (pure-sky win frame, camera buried in hillside, 50.4% blown-white) each passed every numeric gate tooth and were caught ONLY by a human eyeball (rule 5). vqoe's probe835 taught the same lesson for video (median GREEN while 100% of frames never decoded). This lib gives every gate a cheap composable tooth: "does this frame LOOK like a scene a player would accept?" Metrics (all integer, deterministic, RGB24 caller fb like nx_swgpu/nx_gamehud): [0] blown_permil -- pixels clipped to near-white (the tonemap-missing class) [1] black_permil -- pixels near-black (the void/underexposed class) [2] edge_permil -- luminance-step density (detail present at all; pure sky scores ~0) [3] cedge_permil -- edge density in the CENTER THIRD (framing: the subject belongs mid-frame; a sky-stare or floor-stare has its detail off-center or absent) [4] flat_permil -- horizontal-run flatness (px == right neighbor); gradient skies are flat fs_verdict applies DATA-DRIVEN thresholds (caller-supplied; keep them in a conf, rule 11). HONEST RESIDUAL: cannot judge SEMANTICS (is that the right building?) -- it kills the gross framing classes only; the realism-loop critic stays the fidelity judge. LIB, no main. license_tier: ORIGINAL