Brightness term for the density guard's keep-fraction thinning: a node
drawing only a keep fraction of its elements has its opacity multiplied by
1/keep so the sum-projected (or optical-depth) result stays at the
unthinned aggregate. 1 for an unthinned or unstamped node. The guard's
ladder already floors keep (config minKeepFraction), so no cap here.
Brightness term for the density guard's keep-fraction thinning: a node drawing only a
keepfraction of its elements has its opacity multiplied by1/keepso the sum-projected (or optical-depth) result stays at the unthinned aggregate.1for an unthinned or unstamped node. The guard's ladder already floorskeep(configminKeepFraction), so no cap here.