Pipeline architecture

Lifecycle Kit is a library of five independent stages, not a framework. A consumer owns scheduling, persistence, seeding, and final rendering; the package owns deterministic transformation and validation of the data it receives.

Boundary types

The important handoffs are plain data:

• Composition represents tissue fractions.
• Path represents vector geometry from the forms stage.
• PaletteRamp contains shadow, base, pigment, and highlight colours.
• AssembledPart carries geometry, depth, light, and occlusion ready for a renderer.

The stages deliberately do not own a DOM, canvas, game-engine object, clock, or random-number source. A game can therefore persist a state as JSON, replay it, or process multiple creatures concurrently without cross-talk.

Renderer adapters

The forms package includes SVG and Pixi adapters as convenience renderers, but the core geometry and assemblage outputs are renderer-neutral. Keep engine objects at the edge of an application: feed plain Lifecycle Kit inputs in and adapt its output at the final drawing boundary.

For the exact draw order and the boundary between the built-in SVG/Pixi helpers and an application renderer, see Render a creature.

Persistence

Metabolic state is the one deliberately evolving state model. Use writeMetabolicState() before persisting it; the writer rejects invalid state. Use readMetabolicState() when loading; it migrates known partial legacy records and falls back to a fresh newborn state for corrupt input.

Only metabolic state has a persistence format. Path, PaletteRamp, and AssembledPart are plain serializable values, but they are derived views: keep the world inputs and metabolic/diet history as the durable simulation record, then recompute those views when needed.