forest_spruce_l1

# nring_foliage Foliage and bark for the Nürburgring Drive Eifel forest. One shader draws a whole tree mesh: vertex alpha 0 is bark, alpha above 0 is foliage (and how far it sways with the engine wind). Card levels (`textured = 1`): foliage is cut out of `foliage_texture` (branch sprays / leaf clusters with alpha; the cutoff relaxes from `alpha_cutoff` to `alpha_cutoff_far` over `cutoff_fade` metres because mips thin the alpha), bark samples the tileable `bark_texture`, and a foliage vertex whose uv.y is 2 or more is opaque crown core. Solid levels (`textured = 0`: proxies, far stands) draw flat colours with a distance-faded value-noise breakup. Every instance takes its own brightness and warm/cool shift from a hash of its world origin, the baked vertex shade also darkens ambient so crowns read deep, and foliage gets a weak, rough specular. Normals are authored bent outward from the crown centre and are not flipped on back faces: draw two-sided (cull none) and the cards shade as one volume. `lod_focus` / `lod_near` / `lod_far` give each material a distance window that the forest's ForestDetail component moves with the camera.