nx_textured_tri_fast.nx

nx_textured_tri_fast.nx -- E1-R1 of the raster perf ladder (board S18): the SAME textured-triangle semantics as nx_textured_tri.txtri_render, made incremental. BIT-EXACT by construction: (a) edge functions are affine -> per-pixel re-evaluation (6 muls) becomes +=dE/dx steps (exact ints); (b) UV numerators Nu=w0*u0+w1*u1+w2*u2 are affine too -> row-DDA increments (exact ints), the /area truncating division stays per-fragment so u,v match the reference EXACTLY; (c) bilinear sampling inlines nx_txs_sample_bilinear's CLAMP arithmetic verbatim, with direct row-pointer loads (the wrap-clamp already guarantees in-bounds -- nx_image_get's checks never fire on this path) and >>10 replacing /1024 ONLY where operands are provably non-negative. The equivalence gate lives in nx_raster_bench (fast frame must checksum IDENTICAL to the reference; neg-control: a perturbed scene must NOT match). license_tier: ORIGINAL