The generic normal-mode depthWrite predicate: a (near-)fully-opaque
normal layer writes depth so it occludes additive layers behind it.
Single source of truth — the material caches key on this SAME
predicate so two opacities on either side of the threshold can never
share a cached material (1%-opacity buckets straddle 0.99: 0.985 and
0.994 both bucket to 99 but need different depthWrite).
The generic
normal-mode depthWrite predicate: a (near-)fully-opaque normal layer writes depth so it occludes additive layers behind it. Single source of truth — the material caches key on this SAME predicate so two opacities on either side of the threshold can never share a cached material (1%-opacity buckets straddle 0.99: 0.985 and 0.994 both bucket to 99 but need different depthWrite).