particles

Since 0.6Changed in 0.7

Use it in a scene entity's components list as { "type": "particles", … }. The contract writes the fields flat and refuses unknown keys.

Fields

Field	Type	Required	Allowed values	Description
`preset`	`ParticlePreset`	no	`smoke`, `fire`, `sparks`, `dust`, `steam`, `drips`, `debris`, `glow`	One of the eight built-in looks. Exactly one of `preset` and `effect` is required (particles-source). With a preset, `rate` is the particles per second.
`rate`	`number`	no		Particles per second of a `preset`. Ignored with an `effect` (the effect's own spawn rules apply).
`color`	`string`	no
`material`	`string`	no		A key of scene.assets whose kind is "material": a material file with a `shader` (`blend: add` or `blend: blend`) the sprites draw with instead of the built-in sprite. The shader reads `particleAge`, `particleRandom` and `particleColor` from its SurfaceInput. On HD such an emitter is simulated on the CPU so its shader can draw it; emitters without one stay GPU-simulated. Not supported together with `effect` yet (particles-source).
`effect`	`string`	no		A particle effect (docs/VFX.md): a key of scene.assets whose kind is "effect" (a `.vfx.json` file), a project-relative `.vfx.json` path, "builtin:<preset>" (smoke, fire, sparks, dust, steam, drips, debris, glow) or "builtin:fx/<preset>" (sparks, flame, dust, puff-burst, hit, confetti, speed-lines; docs/VFX.md, Presets). Exactly one of `preset` and `effect` is required (particles-source). An unknown asset or built-in is vfx-effect-missing.
`params`	`object`	no		Values for the effect's declared `params`, by name: a number, [x, y, z], [r, g, b, a] or "#rrggbb[aa]", by the param's type. A name the effect does not declare, or a value of the wrong type, is ignored with a runtime warning. Only with an `effect`.

Rules that can refuse it

feel/impact-silent
particles-effect-unknown
particles-override-ignored
particles-param-unknown
particles-source
render.hd.cloud_shadow_unavailable
render.hd.screen-fx-views
vfx-effect-missing

Example

From the contract's tested fixture fixtures/contract/full20/scene.json#smoke-vent.

{
  "type": "particles",
  "preset": "smoke",
  "rate": 24,
  "color": "#9AA0A6"
}