light op• Data kinds: normalmap → rgb
• Call: import gfx2d; gfx2d.normal_map_shade(normals, light_dir=(0.0, 0.0, 1.0), ambient=0.1, diffuse='reference', specular=0.0, shininess=32.0, view_dir=(0.0, 0.0, 1.0), scheme='okabe_ito') (or opsgfx2d.get("normal_map_shade"))
Shade a 2-D normal map with one directional light (Lambert + Blinn 1977).
`normals is a normalmap: (H, W, 3)` unit vectors, as
:func:normal_map_decode returns. Non-unit input raises rather than being
normalised for you — a normal map that is not normalised is usually a map
that was never decoded, and quietly fixing it hides the mistake.
`out = diffuse * (ambient + max(n·l, 0)) + specular * max(n·h, 0)^shininess`
with `h` the normalised halfway vector between light and view.
Directions are `(x, y, z)` with **+x right, +y down, +z out of the
screen** — the same handedness as the pixel grid, so a light at
`(0, -1, 1)` comes from above the screen. Getting the sign of y wrong
flips the perceived relief (bumps become dents) without raising anything;
that is the one thing to check on first render.
• 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.
• gfx2d_scene — py -3.11 examples/gfx2d_scene.py
rgb as input)srgb_to_linear · linear_to_srgb · blend_mode · light_mask · normal_map_decode · bloom · vignette · chromatic_aberration
light)radial_light · light_mask · normal_map_decode · shadow_cast_2d
*Provenance: gfx2d.py — GFX2D 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.