A meadow over your ground (world.grass) #

Thousands of grass tufts over the ground, placed once and drawn instanced. Readable offline: gripforge docs world-grass, or the MCP tool gripforge_docs (topic world-grass). The other environment kits are in the environment guide.

What it is for #

world.grass collects what the world declares (the ground or terrain extent, the routes, the clearings, the water, the thickets) and places the meadow once, deterministically from a seed: a jittered grid over the ground, emptied on routes, clearings and water, taller and denser in the thickets. The presenter draws each tuft as a pair of crossed quads that bend in the wind, darker at the roots, fading with the distance to the camera. The placement runs over the first ticks, a slice of cells at a time.

Turn it on #

{ "id": "world.grass", "config": { "density": 1 } }

It requires game.engine. It needs a ground to grow on: world.ground, an arena or a terrain (size 0 uses its extent).

First example #

<!-- test: kits/game_engine/host/tests/world_scenery.rs::the_shares_are_live_settings --> A project with an arena and world.grass at density 1. After one tick the meadow is placed; setting coverage to 0.5 hides about half of it, and the tufts that stay are the same ones in the same order.

{ "op": "step", "ticks": 1 }
{ "op": "call", "service": "world.grass.settings", "method": "set", "args": ["coverage", 0.5] }
{ "op": "call", "service": "world.grass", "method": "placements", "args": [] }

Settings and defaults #

Services, events, hooks #

• world.grass (service): placements() the tufts shown, look() the colours, size and wind, regenerate() places the meadow again (answers the number of tufts), coverage(share?) reads or sets the share shown (clamped to 0 to 1).
• world.grass.settings (service): the live settings other kits can drive, with keys(), get and set. One key today: coverage, so world.bindings can grow the meadow from a variable.
• grass.changed (event): the meadow was placed again; payload count. Presenters redraw on it.
• scene.entered, terrain.edited (events, listened to): the meadow is placed again, so a scene change or a terrain edit re-grows it.
• grass.place (hook): { size, seed, density, maxCount }, asked before each placement; seed, density and maxCount can be changed. It cannot be cancelled: a meadow is always placed (coverage 0 shows none).

{ "id": "winter", "hook": "grass.place", "set": { "density": 0.5 } }

Modding #

Every setting above is moddable, as is the live setting coverage. Without a tap on grass.place the kit plays as before.

Saves #

The save keeps only coverage; the meadow itself is rebuilt from the config and the world.

Engines #

Web and the native player. There is no separate Godot, Unity or Unreal delivery.

When it does not do what you expect #

• No grass: the ground has no extent (size 0 and no ground or terrain), or coverage is 0.
• Grass on a road: the route is not declared by lanes.routes; raise clearance.
• Grass missing on sand or rock: on a terrain, only grass, meadow and moss layers grow; set everywhere to true.
• Too few tufts for the density: maxCount thins the grid; raise it.
• A change of config has no effect: call regenerate().

Limits #

One meadow per game, no per-tuft collision or interaction, no trampling. Beyond maxCount tufts the grid is thinned, not extended.

Versions #

Kit 1.3.0 (service contract 1.2.0). coverage since 1.1.0, live settings since 1.2.0, the grass.place hook since 1.3.0.