particle_sort_indices

The last stage of a sprite emitter's per-frame back-to-front sort. One thread per draw slot, once per frame the emitter sorts.

Thread n reads which particle the sort put n-th and writes that particle's two triangles into the n-th six-index run of the emitter's index buffer. The vertices stay where the update pass wrote them, so the whole sort costs one u32 per slot of traffic and nothing per vertex.

A slot the sort resolved to the sentinel holds no live particle. It takes six copies of index 0 — three zero-area triangles the rasterizer drops.

Bindings

Slot	Access	Contents
indices	read	The final permutation: entry n names the slot that draws n-th.
out_indices	read_write	The emitter's index buffer, six indices per slot.
sortview	read	[0] slot count.

Dispatch one workgroup of 64 per 64 slots.