# wf_sheet Waterfall curtain: a ballistic vertex path off the lip, packet-timed ribbon noise that tears with distance fallen, aeration to white, backlit scatter and a refracted background. The vertex stage reads each vertex's place on the sheet back from the grid's own position: `u` across a 6.8-wide grid and `s` from 0 at the lip (`base_y`) to 1 at the bottom of `height`. It then places the vertex on the path water takes off a lip: it leaves with `out_speed` and falls under gravity (9.81), so after falling a distance `s * height` it has moved `out_speed * t` outward along -Z from `z0`. The sheet widens by `spread` toward the bottom, sways a little more the farther it has fallen, and is pushed along -Z by `z_bias`. The fragment pins its pattern to packets of water: a packet released at time `t0` has fallen `0.5 * g * (t - t0)^2`, so the noise is sampled at the time each point's water left the lip. As the water speeds up its streaks stretch, and the sheet tears into ribbons because the breakup threshold rises with the distance fallen. Broad tongues, fine strands and grain come from `fx_noise` seeded by `seed`. Aeration turns the water from a deep green-blue to white where the flow is thin and fast, crests catch the sun through a Henyey-Greenstein phase (g 0.55), and the cliff behind shows through, bent by the ripples (`zero_scene_color_refract`). The tail fades into the plunge over the last 7 percent and the top edge fades in at the lip. Three materials use it, all alpha-blended with culling off and depth writes off, and the `wf_water` graph (`waterfall/wf_water.procGraph`) hangs one curtain from each on a 6.8 by 21.5 grid in the Procgen Effects Showcase world's `fx_falls` scene: | Material | `width` | `out_speed` | `spread` | `seed` | `density` | `z_bias` | |---|---|---|---|---|---|---| | `wf_sheet_back` | 9.8 | 1.45 | 0.2 | 11 | 1.1 | -0.32 | | `wf_sheet_main` | 9.2 | 1.7 | 0.22 | 3 | 1.15 | 0 | | `wf_sheet_front` | 7.6 | 1.95 | 0.26 | 27 | 0.8 | 0.34 | All three use `z0` 42, `base_y` 21.9 and `height` 21.5. The shader includes `fx_noise`, `zero::scene_depth` and `zero::scene_color`. ## Properties | Property | Type | Default | Meaning | |---|---|---|---| | `width` | float | 6.6 | Width of the curtain at the lip (range 0.5 to 40). | | `height` | float | 21.5 | Height the water falls (range 1 to 80). | | `z0` | float | 0 | World Z of the lip (range -1000 to 1000). | | `base_y` | float | 21.9 | World height of the lip (range -10 to 100). | | `out_speed` | float | 1.7 | Speed at which the water leaves the lip along -Z (range 0 to 8). | | `spread` | float | 0.22 | How much wider the curtain is at the bottom, as a fraction of `width` (range 0 to 1). | | `seed` | float | 3 | Seed for the curtain's noise and sway (range 0 to 99). | | `density` | float | 1.15 | Multiplies the sheet's body before it becomes alpha (range 0 to 3). | | `z_bias` | float | 0.0 | Shift of the whole curtain along -Z (range -3 to 3); the three curtain materials use -0.32, 0 and 0.34. | | `vertexBoundsDilation` | float | 3.5 | How far the vertex hook moves a vertex past the mesh, in world units: the culling bounds grow by it so a moved vertex stays inside them. |

# effectShowcase The procedural effects of the Procgen Effects Showcase world. Each one is a `.procGraph` that plays through a `Generator`, and every shader, material and module a graph draws with sits beside it in this package, so the package carries everything its graphs need. Each graph's README says what it makes, how to place it and what each of its inputs changes. ## Contents | Folder | Graphs | What they make | |---|---|---| | `combat/` | `impact`, `muzzleFlash`, `tracer` | A round striking a hard surface, the bloom at a barrel as a weapon fires, and the glowing streak of a round in flight. They draw with `fxFlash`, `fxSmoke` and `fxSpark` in `combat/shaders/`. | | `blast/` | `wall_blast` | A charge blowing a breach through a stone block wall, on a 9.6 s loop. | | `storm/` | `storm`, `tower` | A thunderstorm around a lone tower: wind-driven rain, lightning striking on the schedule `schedule.module` keeps, and sparks and smoke where strikes land. `tower` is the stone keep it stands around. | | `rift/` | `arcane_rift` | A rift tearing open in the ground, its motes and rubble moved by the compute shaders in `rift/compute/`. | | `dragon/` | `dragon_breath` | A dragon's fire breath sweeping a courtyard: a flame jet, rolling smoke and drifting embers. | | `launch/` | `launch` | A heavy-lift rocket liftoff on one looping timeline, with the heat-haze material `rk_haze_mat`. | | `waterfall/` | `wf_env`, `wf_water`, `wf_spray`, `wf_foam`, `wf_mist` | A waterfall built in parts: the cliff, basin and boulders, the falling and still water, the droplets, the foam where the falls land, and the mist with its rainbow. Its water materials are in `waterfall/materials/`. | | `shaders/` | | `fx_noise`, the noise functions the waterfall and wall blast shaders include. | ## Playing one A graph plays on a `Generator` component bound to it: ```lua -- `graph` is the graph's reference: the AssetRef `asset.resolve` or a search returns for it. local e = entity.spawn("impact", { position = { 0, 1, 0 } }) e.component.add("Generator", { graph = graph, playOn = "load" }) ``` Set a graph's inputs with the Generator's `params`, e.g. `params = { size = 3 }`.