Struct ParticleEmitterDef 

pub struct ParticleEmitterDef {

    pub model: SpriteModelId,
    pub pos: [f32; 3],
    pub shape: EmitterShape,
    pub spawn: SpawnMode,
    pub lifetime: Range<f32>,
    pub velocity: VelocityDef,
    pub gravity: [f32; 3],
    pub drag: f32,
    pub collision: CollisionMode,
    pub scale: f32,
    pub scale_end: Option<f32>,
    pub spin: Range<f32>,
    pub fade_in_frac: f32,
    pub fade_out_frac: f32,
    pub tint: Rgb,
    pub tint_end: Option<Rgb>,
    pub material: u8,
    pub lighting: BillboardLighting,
    pub shadows: ShadowFlags,
}

Recipe for add_emitter. Construct with ParticleEmitterDef::new and override what the effect needs; there is no Default because a def is meaningless without a live SpriteModelId.

Fields

model: SpriteModelId

The kv6 sprite model every particle instantiates (a puff, a spark, a shard) — from add_sprite_model.

pos: [f32; 3]

Emitter position, world space. Movable later via set_emitter_pos.

shape: EmitterShape

Spawn-position distribution around pos (PS.2; default EmitterShape::Point).

spawn: SpawnMode

Spawn behaviour (default SpawnMode::Manual).

lifetime: Range<f32>

Per-particle lifetime, seconds, sampled uniformly. A degenerate range (end <= start) collapses to start. Clamped to ≥ 1 ms.

velocity: VelocityDef

Initial velocity distribution.

gravity: [f32; 3]

Constant acceleration, world units/s² — gravity is positive z (default [0, 0, 22], a decent arcade fall).

drag: f32

Linear drag coefficient, 1/s: each step removes drag · vel · dt. 0.0 = ballistic; smoke wants ~1-3.

collision: CollisionMode

Voxel-collision reaction (PS.3; default CollisionMode::None). Only the _with_scene update/tick variants test it.

scale: f32

Uniform base scale applied to the instance basis (1.0 = authored model size). The rendered scale clamps to ≥ 0.05 — a degenerate basis silently skips drawing.

scale_end: Option<f32>

End-of-life scale (PS.2): the particle lerps scale → scale_end over its lifetime — growing smoke, shrinking sparks. None (default) = constant.

spin: Range<f32>

Spin rate about the world vertical, radians/second, sampled uniformly per particle (PS.2) — a symmetric range like -3.0..3.0 spins debris both ways. Default 0.0..0.0 = no spin.

fade_in_frac: f32

Fraction of the lifetime over which alpha ramps 0 → 255 at the start (PS.2) — smoke that condenses in rather than pops. 0.0 (default) = born fully opaque.

fade_out_frac: f32

Fraction of the lifetime over which alpha fades 255 → 0 at the end (0.25 = the last quarter). 0.0 = no fade, particles vanish at full opacity.

tint: Rgb

Per-particle RGB tint, packed 0x00RRGGBB (white = no-op).

tint_end: Option<Rgb>

End-of-life tint (PS.2): lerped per channel from tint over the lifetime — white-hot → red → dark ember. None (default) = constant.

material: u8

Voxel-material id for every particle (TV palette; 0 opaque). Smoke wants an alpha/volumetric material, sparks additive.

lighting: BillboardLighting

Shading-normal mode (default BillboardLighting::FaceNormal; glowing effects want BillboardLighting::FullBright).

shadows: ShadowFlags

Shadow participation. Defaults to neither cast nor receive — hundreds of shadow-casting particles are a perf trap; opt back in per effect.

Implementations

impl ParticleEmitterDef

pub fn new(model: SpriteModelId) -> Self

A def with every field at its documented default: manual spawn at a point at the origin, 1-2 s lifetime, no initial velocity, arcade gravity, no drag, constant unit scale, no spin, fade out over the last quarter, constant no-op tint, opaque material, face-normal lighting, shadows off.

Trait Implementations

impl Clone for ParticleEmitterDef

fn clone(&self) -> ParticleEmitterDef

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ParticleEmitterDef

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.