open-standards/wai/changes/2026-11-09-compose-fields-and-conditioned-layers.md

The composing page computes fields and conditioned refinements in WebAssembly

• wai-web compose bundle (src/compose_stage.rs, with wai/field_int and wai/splat_exact added to the feature): ComposedField, a wai.field.int_grid base and the wai.field.int_refine levels offered to it, wai::int_field::FieldStages under staged-delivery §4.1 with a hold bound of zero, rendered at the field's own view after every stage, with a render-work limit checked before anything is rendered (cost_over_limit); ComposedStage, wai::staged::StageSink with the side planes a wai.image.int_cond_refine layer reads held by the page: pictures decoded from wai.image.png through an envelope's capability or its fallback, splat sets decoded through wai.splat.int_codec with the parameter set the page holds, and a render entry's frame rendered in the page by wai-splat-render:i1 at its pose; composeSide, the side planes a layer names. The decode, the levels, the network, the residual, the render and every check are wai-rs's, compiled to wasm32; nothing is written a second time in JavaScript.
• compose.js: a field is presented as the picture, rendered in the tab at the view its payload pins, and a picture of an image component is decoded in the tab, each held to its signed digest first. A piece whose base has layers presents the base, then takes each layer as it arrives: checked against its entry, its next stage computed in WebAssembly, held to the stage hash its entry states, and only then presented. A conditioned layer's side planes come from the piece's asset entries: an object is held as a plane only where the page decodes it under the device's profile, its bytes pass their entry's checks and its output holds its digest. A layer refused anywhere (side-absent, side-not-exact, layer-gap, object-hash, prefix-digest and the rest) leaves the stage below presented, and the page says why. The dispatch record lists each piece's layers with their outcome, reason, stage, stage hash and the side planes each read. A field and the side objects route wasm and are never put to the user agent (platform-decode maps none of them); the refinement capabilities the page applies are in the report's wasm leg.
• compose/staged/: four packages of one image component each (fields, fields-digest, cond, cond-not-exact), sealed with the package's key from objects of volumetric-conformance/fields/ and staged-conformance/cond/, byte for byte, each entry's prefix digest computed natively and held to the corpus's statement; the native tests require the committed bytes. run.mjs adds the staged cases (--only staged runs them alone): every field renders to its scene's frame digest, read back from the canvas; with each level's delivery held back and released one at a time, the coarse field is presented before its first level is asked for and every stage before the next level; a stage whose signed digest is another's, a level with a byte flipped, a side object withheld or flipped, the splat decoder left out of the profile, and a plane held only through its fallback are each refused with their code and the stage below presented.
• browser-sink §14: the layers table names wai.field.int_grid; §14.3 the rule for the field, its levels, the conditioned layer and its side objects, and the dispatch record's layers; §14.4 the field's and the picture's digests; a new §14.5, Refinement layers, what the page computes and checks for each layer, in order; §14.7 the staged packages; §14.8 their conformance. The former §14.5 to §14.7 are now §14.6 to §14.8.
• CI: wai-web-wasm.yml runs the compose bundle's native tests (compose_stage::), and triggers on wai/volumetric-conformance/.