#1171 GI: glass reads the radiance cache smoothly (no cell grid) #1173

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sky_line merged 1 commit from TheSlowly/Slipstream:gi-forward-cache-smooth into main

2026-10-29 02:07:09 +00:00

TheSlowly commented

2026-10-28 00:00:06 +00:00

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Fixes #1171: with GI on, glass showed the radiance cache's cell grid (squares on windows, polygons on tilted or curved panes).

A forward-lit surface has no GI pixel of its own. giForwardRefl took its ambient and its reflection occlusion from the one cache cell at the fragment, unfiltered.

giCacheForward blends the 8 cells around the point (trilinear). Cells with no estimate yet drop out, and the probes stand in for their share, so there's no seam where the cache's cover ends.
RenderVKGIForwardCacheFilter (live): 2 = trilinear (default), 1 = the 4 in-plane cells (cheaper), 0 = as before.
Cost: up to 8 hash finds instead of 1, on forward GI fragments only.

Tested in-world on the observatory windows and dome (0 vs 2).

Fixes #1171: with GI on, glass showed the radiance cache's cell grid (squares on windows, polygons on tilted or curved panes). A forward-lit surface has no GI pixel of its own. `giForwardRefl` took its ambient and its reflection occlusion from the one cache cell at the fragment, unfiltered. - `giCacheForward` blends the 8 cells around the point (trilinear). Cells with no estimate yet drop out, and the probes stand in for their share, so there's no seam where the cache's cover ends. - `RenderVKGIForwardCacheFilter` (live): 2 = trilinear (default), 1 = the 4 in-plane cells (cheaper), 0 = as before. - Cost: up to 8 hash finds instead of 1, on forward GI fragments only. Tested in-world on the observatory windows and dome (0 vs 2).

TheSlowly added 1 commit

2026-10-28 00:00:07 +00:00

#1171 GI: glass and other forward surfaces read the radiance cache smoothly (no cell grid) afcccc6f64

A forward-lit surface (alpha-blend glass, forward frames) has no GI pixel of its own: its
ambient and its reflection occlusion (GI / probe irradiance) came from the ONE radiance-cache
cell at the fragment. On glass, which is mostly reflection, every cell got its own flat tint:
squares on a window facing an axis, triangles / polygons where a tilted or curved pane cuts
the cubes; their size followed RenderVKGICacheCellSize.

giCacheForward weights the 8 cells around P by their centres (trilinear, in the cell's
distance level and face bucket); cells without an estimate drop out and the probes stand for
their share (giForwardRefl mixes toward the probe irradiance by the found weight), so the
cache's cover ends without a seam either. giCellKey is split into giCellLevel / giCellAxis /
giCellBucket / giCellKeyQ (same keys).

RenderVKGIForwardCacheFilter (live, GI_FWD_FILTER_SHIFT bits 26-27): 2 trilinear (default),
1 the 4 cells of the face's own layer (half the finds; a tilted face keeps a step where it
crosses a layer -- the #1052 occlusion cull's in-plane rule), 0 the single cell as before.

Cost: forward GI fragments only: up to 8 hash finds instead of 1 (corners under 1e-3 weight
skipped), next to the probe walk and SSR they already run. Deferred surfaces unchanged.

sky_line referenced this pull request from a commit

2026-10-29 02:06:49 +00:00

Review nits for PRs #1254 and #1173

sky_line commented

2026-10-29 02:07:09 +00:00

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Merged to main as 71dc58b9b2 by cherry-pick (with review nits in ac757d72fc), after review and an aggregate build. Thanks! Commit messages were reworded to drop other viewers' names (repo rule: no viewer names in commits/PRs/tickets); credit goes in the release notes and About.

Merged to main as 71dc58b9b2 by cherry-pick (with review nits in ac757d72fc), after review and an aggregate build. Thanks! Commit messages were reworded to drop other viewers' names (repo rule: no viewer names in commits/PRs/tickets); credit goes in the release notes and About.

sky_line manually merged commit 71dc58b9b2 into main

2026-10-29 02:07:09 +00:00

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