Class SplashEmitter

Rain on the ground near the camera as MPM splashes: each update a seeded number of drops (rain × splashes × area × dt, fractions carried over) hit the terrain within radius of center, and each spawns a few water particles in the solver: on a puddle a crown and a jet, on dry ground a low scatter. Those particles are tagged (SPLASH_TAG); the retire pass from SplashEmitter.prepare removes them when they land again (their water is already counted in the puddles). With a PuddleField, the rain also feeds it. Far from the camera, keep drawing rain as streaks; this is the near field.

Example

const puddles = new PuddleField({ resolution: [96, 96], cellSize: 0.05, origin: [-2.4, -2.4] }, height)
const rain = new SplashEmitter(mpm, { rain: 12, radius: 2 }, { height, puddles })
// each frame:
rain.set({ center: [camera.position.x, camera.position.z] }).update(dt)
renderer.compute([...mpm.prepare(dt), ...rain.prepare()])

Index

Constructors

constructor

new SplashEmitter(
    target: SplashTarget,
    input?: {
        center?: [number, number];
        material?: string;
        maxPerFrame?: number;
        particles?: [number, number];
        puddleDepth?: number;
        radius?: number;
        rain?: number;
        retireOutside?: boolean;
        seed?: string | number;
        soak?: number;
        speed?: number;
        splashes?: number;
    },
    __namedParameters?: {
        height?: MPMHeightFn | null;
        puddles?: PuddleField | null;
    },
): SplashEmitter
An emitter into target (an MPMSolver, or an MPMReference for tests) over height.
Parameters
- target: SplashTarget
- input: {
      center?: [number, number];
      material?: string;
      maxPerFrame?: number;
      particles?: [number, number];
      puddleDepth?: number;
      radius?: number;
      rain?: number;
      retireOutside?: boolean;
      seed?: string | number;
      soak?: number;
      speed?: number;
      splashes?: number;
  } = {}
  - Optionalcenter?: [number, number]
    
    Centre of the splash area, world x and z.
  - Optionalmaterial?: string
    
    Material of the splash particles (one of the solver's).
  - OptionalmaxPerFrame?: number
    
    Most splashes per update (the rest of that frame's are dropped).
  - Optionalparticles?: [number, number]
    
    Particles per splash: on dry ground (a low scatter of droplets) and on a puddle (a crown plus a central jet).
  - OptionalpuddleDepth?: number
    
    Puddle depth from which a drop splashes as onto water, metres.
  - Optionalradius?: number
    
    Splashes land within this radius of center, metres (e.g. the near field around the camera).
  - Optionalrain?: number
    
    Rain rate, mm/h (0: no rain; puddles drain and dry).
  - OptionalretireOutside?: boolean
    
    Also remove any particle that leaves the solver's domain (a stream running off its side), instead of freezing it.
  - Optionalseed?: string | number
    
    Seed of the impact positions and splash shapes.
  - Optionalsoak?: number
    
    Also remove stray water: a particle on its own (grid mass at its node below this many full cells of 1000 kg/m³) resting on the ground soaks in, instead of lying there as a 15 mL bead. 0: off.
  - Optionalspeed?: number
    
    Launch speed of the splash droplets, m/s (a crown on water; dry-ground droplets fly lower and wider).
  - Optionalsplashes?: number
    
    MPM splashes per m² per second per mm/h of rain: the few visible splashes among the real drop impacts (~70 per m²·s per mm/h).
- __namedParameters: { height?: MPMHeightFn | null; puddles?: PuddleField | null } = {}
Returns SplashEmitter
- Defined in particles/src/mpm-water.ts:404

Properties

`Readonly`impacts

impacts: SplashImpact[] = []

The last update's impacts.

options

options: SplashOptions

Resolved settings.

`Readonly`puddles

puddles: PuddleField | null

The puddles the rain feeds (if any).

spawned

spawned: number = 0

Splashes spawned so far (the serial of the next one: seeds its random numbers).

Methods

dispose

dispose(): void
Frees the GPU pass.

Returns void
- Defined in particles/src/mpm-water.ts:485

prepare

prepare(): ComputeNode[]
The retire pass (GPU solvers only): removes splash particles that have landed (moving down within half a cell of the ground), stray water soaking in (soak) and, with retireOutside, any particle outside the domain. Batch it after the solver's passes: renderer.compute([...mpm.prepare(dt), ...rain.prepare()]).

Returns ComputeNode[]
- Defined in particles/src/mpm-water.ts:476

set

set(
    input: {
        center?: [number, number];
        material?: string;
        maxPerFrame?: number;
        particles?: [number, number];
        puddleDepth?: number;
        radius?: number;
        rain?: number;
        retireOutside?: boolean;
        seed?: string | number;
        soak?: number;
        speed?: number;
        splashes?: number;
    },
): this
Merges input into the settings.
Parameters
- input: {
      center?: [number, number];
      material?: string;
      maxPerFrame?: number;
      particles?: [number, number];
      puddleDepth?: number;
      radius?: number;
      rain?: number;
      retireOutside?: boolean;
      seed?: string | number;
      soak?: number;
      speed?: number;
      splashes?: number;
  }
  - Optionalcenter?: [number, number]
    
    Centre of the splash area, world x and z.
  - Optionalmaterial?: string
    
    Material of the splash particles (one of the solver's).
  - OptionalmaxPerFrame?: number
    
    Most splashes per update (the rest of that frame's are dropped).
  - Optionalparticles?: [number, number]
    
    Particles per splash: on dry ground (a low scatter of droplets) and on a puddle (a crown plus a central jet).
  - OptionalpuddleDepth?: number
    
    Puddle depth from which a drop splashes as onto water, metres.
  - Optionalradius?: number
    
    Splashes land within this radius of center, metres (e.g. the near field around the camera).
  - Optionalrain?: number
    
    Rain rate, mm/h (0: no rain; puddles drain and dry).
  - OptionalretireOutside?: boolean
    
    Also remove any particle that leaves the solver's domain (a stream running off its side), instead of freezing it.
  - Optionalseed?: string | number
    
    Seed of the impact positions and splash shapes.
  - Optionalsoak?: number
    
    Also remove stray water: a particle on its own (grid mass at its node below this many full cells of 1000 kg/m³) resting on the ground soaks in, instead of lying there as a 15 mL bead. 0: off.
  - Optionalspeed?: number
    
    Launch speed of the splash droplets, m/s (a crown on water; dry-ground droplets fly lower and wider).
  - Optionalsplashes?: number
    
    MPM splashes per m² per second per mm/h of rain: the few visible splashes among the real drop impacts (~70 per m²·s per mm/h).
Returns this
- Defined in particles/src/mpm-water.ts:412

setHeight

setHeight(height: MPMHeightFn | null): this
Replaces the terrain height function.
Parameters
- height: MPMHeightFn | null
Returns this
- Defined in particles/src/mpm-water.ts:418

update

update(dt: number): number
Spawns this frame's splashes into the target and advances the puddles. Returns how many splashes.
Parameters
- dt: number
Returns number
- Defined in particles/src/mpm-water.ts:425

Class SplashEmitter

Example

Index

Constructors

Properties

Methods

Constructors

constructor

Parameters

Optionalcenter?: [number, number]

Optionalmaterial?: string

OptionalmaxPerFrame?: number

Optionalparticles?: [number, number]

OptionalpuddleDepth?: number

Optionalradius?: number

Optionalrain?: number

OptionalretireOutside?: boolean

Optionalseed?: string | number

Optionalsoak?: number

Optionalspeed?: number

Optionalsplashes?: number

Returns SplashEmitter

Properties

Readonlyimpacts

options

Readonlypuddles

spawned

Methods

dispose

Returns void

prepare

Returns ComputeNode[]

set

Parameters

Optionalcenter?: [number, number]

Optionalmaterial?: string

OptionalmaxPerFrame?: number

Optionalparticles?: [number, number]

OptionalpuddleDepth?: number

Optionalradius?: number

Optionalrain?: number

OptionalretireOutside?: boolean

Optionalseed?: string | number

Optionalsoak?: number

Optionalspeed?: number

Optionalsplashes?: number

Returns this

setHeight

Parameters

Returns this

update

Parameters

Returns number

Settings

On This Page

`Optional`center?: [number, number]

`Optional`material?: string

`Optional`maxPerFrame?: number

`Optional`particles?: [number, number]

`Optional`puddleDepth?: number

`Optional`radius?: number

`Optional`rain?: number

`Optional`retireOutside?: boolean

`Optional`seed?: string | number

`Optional`soak?: number

`Optional`speed?: number

`Optional`splashes?: number

`Readonly`impacts

`Readonly`puddles

`Optional`center?: [number, number]

`Optional`material?: string

`Optional`maxPerFrame?: number

`Optional`particles?: [number, number]

`Optional`puddleDepth?: number

`Optional`radius?: number

`Optional`rain?: number

`Optional`retireOutside?: boolean

`Optional`seed?: string | number

`Optional`soak?: number

`Optional`speed?: number

`Optional`splashes?: number