grass_material.shader

Grass, shaded root to tip with per-blade colour variation and a soft half-lambert wrap.

The colouring reads uv.y as height along a blade — 0 at the root, 1 at the tip — and darkens the roots while warming the tips. Per-blade variation comes from a hash of the fragment's world xz on a 10 cm grid, so every fragment of one blade shares a seed and neighbouring blades drift apart in hue and brightness. The lighting is a diffuse half-lambert wrap kept below saturation, so this shader returns its own final colour instead of a PBR surface.

sway is how far the vertex stage bends each vertex along its blade, and it is what tells this shader that its mesh is a blade mesh: the bend scales with uv.y², so a vertex at the root holds still while the tip swings hardest. It defaults to 0, at which every vertex arrives where the mesh put it — a material that leaves it there shades a surface without moving it. @builtin::materials.grass is that ground surface; @builtin::materials.grass_blades sets sway to 1 for a blade mesh.

Properties

• base_color — the grass green the root→tip gradient is built from.
• sway (0..4, default 0) — how far each vertex bends along its blade.