Type Alias GeneratorMemory

Per-particle scratch storage that lets stochastic generators "remember" a random sample they rolled at spawn time, so subsequent frames produce the same value for the same particle.

Each Particle owns one GeneratorMemory (see Particle.memory) that starts empty and is cleared on Particle.reset() when the particle is recycled. A particle's memory is independent from every other particle's.

Lifecycle (per spawn)

For every generator the particle system uses (startColor, startSpeed, startLife, startSize, startRotation, etc.), the spawn path calls — in a fixed, deterministic order:

1. generator.startGen(particle.memory) — gives the generator a chance to allocate a slot. A generator that needs a per-particle random sample captures the current length as its slot index, pushes the rolled value, and stores the index on itself (typically this.indexCount).
2. generator.genValue(particle.memory, …) — reads back memory[indexCount] to produce the per-frame value. Called once per frame for the particle's lifetime.

Concrete patterns implemented across the codebase:

• Stateless / deterministic (ConstantValue, PiecewiseBezier, Gradient, RandomColor) — startGen is a no-op; genValue derives output from inputs (t, params) alone.
• Sample-once stochastic (IntervalValue, ColorRange, RandomColorBetweenGradient, RandomQuatGenerator) — startGen pushes one random sample into memory; genValue reads it. This is what keeps a given particle's "random" startSize/color/rotation fixed for its life.
• Composite (AxisAngleGenerator, Vector3Function, EulerGenerator) — startGen forwards to children so each child claims its own slot.

Invariants

• Every spawn must call startGen for the same set of generators in the same order. The slot index a generator captures during one particle's spawn must match what it reads for that particle on later frames.
• indexCount lives on the generator (shared across particles), not on memory. It is overwritten on every spawn; that is safe because each genValue call during a spawn happens before the next spawn's startGen.
• The values stored in memory are not aliased — each particle's memory is its own array, so two particles can hold different samples at the same slot without interference.