GPU ribbon/trail authoring and Three.js integration for nachi. Register the package's compiler extensions with core, then use ribbon() and ribbonId() in an emitter. Birth-order storage keeps strip ordering independent from alive compaction.

Three.js is an exact three@0.185.1 peer for the @nachi-vfx/trails/three materializer.

The renderer requires WebGPU storage buffers and indirect draw; WebGL2 reports NACHI_RIBBON_WEBGL2_UNSUPPORTED instead of silently selecting a different trail algorithm.

ribbonId() accepts a non-negative u32 integer or { mode: 'alternating', count, offset? }. Count is a positive u32 value, offset is non-negative, and offset + count - 1 must remain within u32; count 2^32 is rejected before it can wrap to zero in the shader. ribbon() accepts only stretched or tiled UV mode. Compilation requires every statically authored ID to be lower than maxRibbons; NACHI_RIBBON_ID_OUT_OF_RANGE prevents silent strand loss. Factory and registered compiler paths share the package-owned validators.

materializeThreeRibbonDraw() returns a draw with dispose(renderer?). Reuse that mesh while its emitter is alive, or call dispose() before replacing it. Ribbon draws participate in the official Three runtime's visibility, render-order, profiling, pooling, and kernel-release lifecycle; a draw must not be rendered after its effect instance is released.

Use draw.setUserVisible(false) to hide a ribbon independently of runtime culling and draw.setUserVisible(true) to return to runtime visibility. The final rule is runtimeVisible && userVisible, with userVisible defaulting to true. Assigning draw.mesh.visible directly is not persistent because the Three runtime owns that field.