Indirection-only appearance switch — when dedup wins

Both the default and the selected appearance's paint property blocks already exist in the properties buffer — the dedup pool populated them at parse time. Toggling the Museum is a single indirection-table write; the properties buffer is never touched.

Features

Café

Park

Museum

Station

Indirection table — one entry per feature (4 bytes each)

feature 0 → block

feature 1 → block

feature 2 → block

feature 3 → block

Properties buffer — three pre-allocated blocks; this row never changes on toggle

block 0 · default

text-color: #4a78c9

block 1 · dimmed

text-color: #8a91a3

block 2 · selected

text-color: #ff5722

What got rewritten

indirection table written (cumulative)

0 bytes

properties buffer written (cumulative)

0 bytes

Each toggle re-evaluates the Museum's appearance, gets a paint block, and asks the dedup pool whether that block already exists. It does (block 0 or block 2), so the engine just repoints indirection[2] (a single 4-byte write) and the properties buffer is left alone. This is the cheapest update path the UBO model supports today; the "representation index" work described in the Epilogue extends it so every paint-only switch lands here by construction.