nx_relief_lib.nx

nx_relief_lib.nx -- ★THE ONE OWNER OF THE SKIN MICRO-RELIEF LAW, and of the height field the baked normal map is made of. Extracted 2026-08-25 so the BAKER and the SDF RENDERER cannot disagree about the relief they are respectively writing and reading. [@penner2011] /compare/graphics row "RENDER: pre-integrated SSS bound to baked normals". WHY A LEAF LIB AND NOT A MIRROR. Until today nx_sdfrender carried HAND-COPIED constants (SSS_RELIEF_UM / SSS_RELIEF_LAMBDA_UM) with a comment naming the baker as their source, and a gate tooth that compared the copies. That is the duplicate-ruler defect wearing a test: the copy can only be caught AFTER it drifts, and only if somebody keeps running the comparison. The reason given for the copy was real -- importing nx_nxa_texbake_lib drags nx_nxa + nx_trimesh + nx_png + nx_skin_ita into every consumer of the renderer -- so the fix is not "import the baker", it is to give the law its own LEAF home that both sides import. This file imports nothing but nx_syscalls. THE SEAM, stated so the next reader does not move the wrong half: * THIS FILE owns the PHYSICS -- microns of relief, the wavelength it varies over, the slope that follows from the two, and the value-noise field itself. * nx_nxa_texbake_lib keeps the TEXEL ENCODING -- the byte midpoint/scale that turn a slope into an RGB8 tangent-space texel. That is an atlas format decision, not a property of skin. * nx_sdfrender reads the physics and never sees a texel: a ray-marched implicit surface has no UV, so it samples the SAME height field volumetrically at the lattice its own sampler can resolve. license_tier: ORIGINAL No hw writes (Rule 26).