outline.renderFeature

Outline render feature — screen-space jump-flood (JFA) silhouette rim. Every frame, draws a coloured rim hugging the silhouette of each entity in the @builtin::modules.outline registry. Unlike an extruded shell, the rim is a uniform pixel width and never tears on hard-edge or multi-part meshes, because it is computed from the silhouette in screen space: 1. mask — a geometry pass fills the group's meshes white into a mask RT. 2. seed — silhouette pixels store their own screen position (and an inside flag) into a float position buffer; others a far sentinel. 3. flood — log2(thickness) ping-pong passes propagate the nearest stored position, so every pixel learns the nearest silhouette pixel. 4. composite — blends the rim colour over the scene where a pixel is OUTSIDE the silhouette and within `thickness` of it. The mask, seed and flood run at half resolution (the flood is the cost and a few-pixel rim doesn't need full res); the composite runs at full resolution and samples the half-res field. Position buffers are RGBA32F: RG holds the nearest silhouette position (float32 — half-float rounds coordinates above 2048, which a high-DPI viewport exceeds), and B carries each pixel's own inside/outside mask, so the composite can exclude the interior by the real silhouette rather than by a distance that half resolution makes imprecise. Entities are grouped by (colour, thickness); each group is one mask→seed→ flood→composite chain. An empty registry enqueues nothing.