reflectance op• Data kinds: normalmap → image2d
• Call: import fullseye as fs; fs.ledger.brdf_blinn_phong(normals, light=(0.0, 0.0, 1.0), view=(0.0, 0.0, 1.0), shininess=32.0) (to call the implementation directly, import specularity; specularity.brdf_blinn_phong(normals, light=(0.0, 0.0, 1.0), view=(0.0, 0.0, 1.0), shininess=32.0); from the registry, opsspecular.get("brdf_blinn_phong"))
Blinn's half-vector specular lobe. → (H, W) in [0, 1].
max(n.h, 0) ** shininess where h is the unit bisector of the light and view directions (Blinn 1977), zeroed wherever the surface faces away from either. Exactly 1 where the normal *is* the half-vector — the mirror condition — and it falls monotonically from there.
Unnormalised on purpose. The classical Blinn-Phong lobe does not integrate to a fixed value; its peak is 1 and its energy grows as the exponent shrinks. It is a shading model, useful because its peak location is exact and because it is a *different* lobe shape from brdf_microfacet — a separation routine that only works on one of the two is fitting the lobe, not the model. For an energy-consistent lobe use brdf_microfacet.
Reciprocal in light and view to machine precision (measured exactly 0.0 maximum difference in tests/test_specularity.py), because the half-vector is symmetric and the visibility test covers both sides.
Raises ValueError: *normals* is not an (H, W, 3) field or contains a zero-length normal; *light* / *view* are not non-zero 3-vectors; *shininess* is negative, non-finite, a string or a bool; light and view are exactly opposite.
• specular_photometric family guide
• Sample-data catalog (download URLs / licences) — 2-D uses skimage.data (BSD/public domain) plus synthetic images; 3-D lists download URLs for real data sources (Stanford, PDS, …).
• Operator provenance and references — the sources of the research/methods this op family came from.
• The canonical algorithm (author, year) and its uses are named in the family usage guide above.
• specular_photometric — py -3.11 examples/specular_photometric.py
image2d as input)reflectance)brdf_microfacet · dichromatic_render
*Provenance: specularity.py — SPECULAR operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*
© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.