cave_rock

Triplanar PBR rock surface for the crawler part's cave. Projects the baked rock texture set (preseed/tendril/textures/rock_*) from the three world axes — no UVs or tangents needed on the geometry — and shades with the engine's full metallic-roughness model (directional + point/spot lights + shadows + environment).

Beyond the base triplanar set:

• Cavity occlusion — the displacement_texture height field darkens pits and seams (cavity_strength).
• Macro breakup — the albedo re-projected at macro_scale modulates tone at low frequency so tiling never reads at distance (macro_strength).
• Sediment blend — upward-facing surfaces shift toward sediment_color with matte roughness (sediment_strength), giving the cave floor a settled-dust read.

displacement_texture doubles as the tessellation displacement source: the Tessellation component on the tunnel mesh reads the same slot, so the shading cavity and the displaced geometry always agree.

Used by preseed/tendril/materials/tendril_rock.material.