Renderer · interface

ParticleInstances

A pool's per-particle stream, as a particle material reads it.

interface ParticleInstances

import type { ParticleInstances } from '@driftengine/core';

In depth

Separate from InstanceData — which is a scatter stream, built for placing thousands of static plants — because the two want different things and sharing one of them cost this engine its whole particle look. A blade of grass needs a yaw and a wind response and is opaque; a puff of smoke needs an age, a seed and an opacity, and has no wind of its own because its velocity already carries it.

Lacking those three, the scatter path had to fake the one that matters: a particle "faded" by having its colour multiplied toward black, which is a real fade only if the material is additive. Drawn through the opaque foliage shader it is not a fade at all — it is a grain turning into a black cube — and that, rather than any tuning, is why every effect built on this read as raw.

Properties

Name	Type	Description
`positions`	`Float32Array`	World position, three floats each.
`sizes`	`Float32Array`	Metres from the centre to an edge, a half-width: the quad spans twice this. Then radians of roll about the particle's own axis. This said metres across until 4.8.3, and a caller who took it at its word drew every particle twice as wide as meant.
`spins`	`Float32Array`
`colors`	`Float32Array`	Linear colour, three floats each.
`alphas`	`Float32Array`	Opacity, 0 to 1 — a real one, not a colour standing in for it.
`ages`	`Float32Array`	Age as a share of this particle's own life, for anything that evolves.
`seeds`	`Float32Array`	Per-particle randomness, so neighbours never animate together.
`velocities`	`Float32Array`	Current velocity, three floats each: what a streak is stretched along.
`frames`optional	`Float32Array`	A sprite's flipbook frame, one float each: its whole part names a cell of the image, counted across then down from the top-left, and its fraction is how far toward the next a batch that blends cells has come. Read by the `'sprite'` material alone. Absent is frame 0.
`heights`optional	`Float32Array`	A sprite's half-height in metres, one float each, beside `sizes`' half-width — a sprite need not be square. Read by the `'sprite'` material alone; absent or 0 is as tall as it is wide.
`count`	`number`
`capacity`	`number`