light op• Data kinds: image2d → image2d
• Call: import fullseye as fs; fs.ledger.shadow_cast_2d(occluder, x, y, steps=None, softness=0.0) (to call the implementation directly, import gfx2d; gfx2d.shadow_cast_2d(occluder, x, y, steps=None, softness=0.0); from the registry, opsgfx2d.get("shadow_cast_2d"))
Visibility of every pixel from a point light at (x, y), as image2d.
Ray-marches the segment from each pixel to the light, sampling occluder (2-D, [0, 1], 1 = fully blocking) at steps points with nearest lookup, and returns 1 - max(occluder along the ray). For a binary occluder that is exactly 0 or 1 — no tolerance involved.
The sample excludes the pixel itself, so an occluder is lit on its own light-facing surface and casts behind itself.
softness > 0 blurs the visibility map by that sigma afterwards, which is a penumbra-shaped lie rather than a penumbra: a real one widens with distance from the occluder. It is offered because it looks right and named so it cannot be mistaken for physics.
steps defaults to the image diagonal, which samples about once per pixel. An occluder thinner than the step spacing can be missed; that is the honest limit of a fixed-step march and the reason steps is an argument.
• 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
image2d as input)dither · raw_black_level · raw_dead_pixel_mask · raw_dead_pixel_correct · lens_shading_gain · lens_shading_correct · raw_apply_gains · raw_demosaic_bilinear
light)radial_light · light_mask · normal_map_decode · normal_map_shade
*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.