ParticleSystem class Particles

A self-contained, CPU-driven particle simulation: storage plus the config, shape, spawner, and module stack that fill and advance it.

The system is pure Dart with no scene-graph or GPU dependency, so it can be driven by a component, a headless test, or a future alternative backend. step advances the simulation with a fixed-timestep accumulator (so the result is independent of frame rate) using semi-implicit Euler integration; after stepping, a renderer reads the live columns out of storage.

Spawning is gated by looping/duration: a looping system emits forever, while a non-looping one stops emitting once its run passes duration (already-live particles still finish their lives). All randomness derives from seed, so a given seed and step sequence reproduce exactly (the basis for byte-for-byte tests and editor scrubbing).

Constructors

ParticleSystem({int maxParticles = 1024, required EmitterShape shape, required Spawner spawner, List<ParticleModule> modules = const <ParticleModule>[], FloatDistribution lifetime = const ConstantFloat(1.0), FloatDistribution startSpeed = const ConstantFloat(0.0), FloatDistribution startSize = const ConstantFloat(1.0), FloatDistribution startRotation = const ConstantFloat(0.0), FloatDistribution startAngularVelocity = const ConstantFloat(0.0), ColorDistribution? startColor, Vector3? gravity, bool looping = true, double duration = 5.0, double fixedStep = 1.0 / 60.0, double maxFrameTime = 0.25, int seed = 0, double prewarm = 0.0})
Creates a particle system. The distributions, shape, spawner, gravity, looping behaviour, fixed-step size, and seed are all configurable; only shape and spawner are required.

Properties

duration ↔ double
The length of one run in seconds (the emit cutoff for a non-looping system).
getter/setter pair
fixedStep → double
The fixed simulation timestep in seconds.
final
gravity → Vector3
Constant acceleration applied to every particle during integration.
final
hashCode → int
The hash code for this object.
no setterinherited
lifetime ↔ FloatDistribution
Per-particle spawn properties sampled (with independent randoms) at birth.
getter/setter pair
looping ↔ bool
Whether the system emits forever; when false it stops emitting past duration.
getter/setter pair
maxFrameTime → double
The largest frame delta honored by step; longer frames are clamped so a hitch cannot spiral the accumulator.
final
modules → List<ParticleModule>
The ordered behaviour stack (forces and over-life evaluators).
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
seed → int
The seed for all spawn randomness.
final
shape ↔ EmitterShape
Where particles spawn and which way they initially head.
getter/setter pair
spawner → Spawner
How many particles to emit each step.
final
startAngularVelocity ↔ FloatDistribution
Per-particle spawn properties sampled (with independent randoms) at birth.
getter/setter pair
startColor ↔ ColorDistribution
The color assigned at spawn (a color-over-life module may overwrite it).
getter/setter pair
startRotation ↔ FloatDistribution
Per-particle spawn properties sampled (with independent randoms) at birth.
getter/setter pair
startSize ↔ FloatDistribution
Per-particle spawn properties sampled (with independent randoms) at birth.
getter/setter pair
startSpeed ↔ FloatDistribution
Per-particle spawn properties sampled (with independent randoms) at birth.
getter/setter pair
storage → ParticleStorage
The backing structure-of-arrays storage; a renderer reads its live prefix.
final
time → double
Seconds the system has been running (advances by whole fixed steps).
no setter

Methods

noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
reset() → void
Removes every live particle and rewinds the clock (the seed stream and fractional spawn accumulator reset, so a restart replays identically).
step(double dt) → void
Advances the simulation by dt seconds in fixed-size steps, draining a clamped accumulator so the outcome is frame-rate independent.
toString() → String
A string representation of this object.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited