SpaceDust

The whole space backdrop for a 6-DOF flight scene — a camera-anchored dust field plus glow, bloom, and a positioned sun — from one marker component.

What it does

SpaceDustComponent is pure data: dust-emitter tuning (capacity, emit rate/radius, size + lifetime ranges), a glow intensity, a bloom weight, and a positioned-sun spec. It carries no runtime handle. On first sight of the entity, SpaceDustSystem wires the scene's visual chrome through this.world.renderer exactly once (a setUp latch): it CPU-rasterises a soft dust-dot sprite and uploads it (createDynamicTexture), starts a continuous, camera-anchored dust emitter that re-seats at the active camera every frame (createParticleEmitter with followCamera), enables the selective glow post-pass (setGlowLayer) and HDR bloom (setBloom), and creates a parallax-free camera-following sun — a directional light plus an emissive disc (createSun). The specks have zero emit power, so they hang in space and the camera flies through them; floating-origin world streaming makes a starfield-of-entities pointless, so the field is pure particle chrome. The live emitter handle lives in a System-side WeakMap, never on the component, and is disposed when the entity leaves the world.

Use it in a scene

{
  "World": {
    "tags": ["world"],
    "components": {
      "SpaceDust": {
        "emitRate": 1800,
        "emitRadius": 60,
        "glowIntensity": 0.9,
        "bloomWeight": 0.15,
        "sun": true,
        "sunDirection": [0, -0.22, 1],
        "sunIntensity": 2.4
      }
    }
  }
}

Props

• capacity (number, default 4000) — max live dust particles; the GPU buffer size.
• emitRate (number, default 1800) — dust particles spawned per second.
• emitRadius (number, default 60) — radius (world units) of the sphere the dust spawns within around the camera.
• minSize / maxSize (number, default 0.04 / 0.12) — per-particle size range.
• minLifeTime / maxLifeTime (number, default 1.4 / 3.2) — per-particle lifetime range, in seconds.
• glowIntensity (number, default 0.9) — selective-glow strength; 0 disables the glow layer.
• bloomWeight (number, default 0.15) — HDR bloom contribution weight; 0 disables bloom.
• sun (boolean, default true) — create the positioned camera-following sun (directional light + emissive disc).
• sunDirection ([x,y,z], default [0, -0.22, 1]) — unit world-space direction the sun's rays travel.
• sunIntensity (number, default 2.4) — directional-light intensity for the sun.
• sunDistance (number, default 2400) — distance from the camera to the sun disc (parallax-free framing).

Events

None. SpaceDust neither emits nor listens for any EventBus events — it is fire-and-forget scene chrome. All of its work happens through the renderer adapter (this.world.renderer), so there is no bus coupling to wire up and nothing downstream to subscribe to. (meta.json emits/listens are both empty by design.)

Dependencies

None required — the System's query is just [SpaceDustComponent]. In practice, though, the backdrop only makes sense with an active camera for the dust and sun to anchor to (the emitter and sun re-seat at the active camera every frame), so it lives alongside the flight-camera stack (CameraState6DOF + a chase camera). It needs no mesh or MeshPrimitive of its own.

Notes

• Put it on the world singleton entity (tag world), next to the other global markers — one SpaceDust per scene. It is not attached to the ship.
• The chrome is applied once, on first sight, behind the setUp latch. Editing the numbers after setup will not re-configure the emitter, glow, bloom, or sun — which is why the debug panel is a read-only readout, not a live-tuning slider panel. Set the values in scene JSON before the scene loads.
• Turn features off by zeroing them: glowIntensity: 0 drops the glow layer, bloomWeight: 0 drops bloom, and sun: false skips the directional light + disc.
• The glow layer ships an empty whitelist — meshes opt in elsewhere (a render-sync pass adds glowing meshes via the adapter), so raising glowIntensity alone won't make everything bloom; only meshes that were opted in will.
• Renderer-agnostic: zero @babylonjs / three imports, and the sprite is rasterised on the CPU (makeDustDotPixels) before upload — the same marker runs under any adapter.
• A companion SpaceDustDebugger component (toggle key Digit8 by default) shows the applied backdrop config in a viz panel if you want to inspect it at runtime.