light op• Data kinds: none → rgb (an op determined by its arguments alone — it takes no image or data input)
• Call: import gfx2d; gfx2d.radial_light(height, width, x, y, radius, intensity=1.0, falloff='smooth', color='emphasis', scheme='okabe_ito') (or opsgfx2d.get("radial_light"))
A radial light map, `rgb (H, W, 3), centred on (x, y)`.
`falloff`:
• `"smooth" — (1 - t^2)^2`, compactly supported: exactly zero at and
beyond `radius`. The default, because a light that ends somewhere is the
only kind you can budget.
• `"linear" — 1 - t`, also compact.
• `"inverse_square" — 1 / (1 + (3t)^2)`, the physical law softened at
the origin. Not compactly supported: it is 10 % of peak at the nominal
radius and never reaches zero, so a scene full of these never gets dark.
The value at the centre is exactly `intensity * color`. This is a
*linear-light* quantity: add lights together, then encode once.
With `intensity > 1 the result leaves [0, 1]` — deliberately, because a
light map is not a picture. :func:light_mask accepts it; the operators that
take an `rgb` *image* reject it with the documented range error rather than
clipping a light budget behind your back.
• 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)light_mask · normal_map_decode · normal_map_shade · 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.