set_rugborder

# playroom_paint Painted wood built from the fragment's world position: long grain streaks down the board, a seam and a per-board tint every `plank_size` metres across it, and broad patches where `wear` rubs the paint back to `wear_color`. Lit through `zero::pbr`, so it renders in forward and deferred alike. Because the pattern is world-space, one material keeps the same physical grain size on a 48 m table slab and on a 3 m skirting board, and a heavily stretched cube does not smear. `plank_size = 0` turns the boards off, which is what the flat painted surfaces (walls, rug, table top) use. Every playroom surface in BLOCKBUSTER 767 is a material on this shader.