Replace the rerender event bus with direct ObjectsManager calls

[sophiedeziel]

Fixes #282, fixes #375 and fixes #278. Alternative to #310

#310 routes property changes through an event bus. This POC takes the opposite direction and removes EventsDispatcher altogether — every notification is a typed callback.

It also delivers what #236 asks for: consumers no longer call render() after changing a property — the library decides per property what kind of update is needed.

---

The two approaches

flowchart TB
  subgraph B["PR 311 — the manager decides, no bus"]
    direction TB
    b1["setter"] --> b2["ObjectsManager"]
    b2 --> b3["group.visible = false"]
    b2 --> b4["uniforms.uColor.value = c"]
    b2 --> b5["material.clippingPlanes = p"]
    b2 --> b6["debounce -> reset -> redraw"]
    b7["notifications"] --> b8["onFrameRendered / onJobUpdated<br/>typed callbacks"]
  end

  subgraph A["PR 310 — every change is an event"]
    direction TB
    a1["setter"] -->|"emit('extrusionColorChange')"| a2(["EventsDispatcher"])
    a2 --> a3["debounce 100ms"]
    a3 --> a4["render()"]
    a4 --> a5["resetScene()"]
    a5 --> a6["rebuild every geometry"]
    a6 --> a7["7023 paths re-walked"]
  end

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Of SceneManagerEvent's 23 members, 21 were …Change events with no listener outside the library — they existed only to trigger a full rebuild. The remaining two were real notifications, and they became callbacks, so the enum and the dispatcher are both gone:

was	is now
frameRendered	SceneManager.onFrameRendered
jobUpdated	GCodePreview.onJobUpdated
streamReadEnd	GCodePreview.onStreamEnd
animationComplete	dropped — renderAnimated() already resolves then

(The addEventListener/EventName API only ever existed inside this branch — it was introduced and removed here, so nothing shipped from develop loses it.)

Breaking changes vs develop:

• GCodePreview.render() is removed — rendering is reactive; use preview.sceneManager.render() / renderAnimated() for a manual draw
• SceneManager's constructor narrows to (opts, job); the onFrame argument becomes the onFrameRendered property
• SceneManagerOptions.nonTravelMoves and the nonTravelmoves field are removed
• SceneManager.inches and initialCameraPosition are no longer public
• processGCode now returns the renderAnimated() promise, and processGCodeStream resolves only once the animated render completes

New callbacks, each holding a single assignable listener:

preview.onJobUpdated = (job) => updateUI();
preview.onStreamEnd = () => updateUI();
preview.sceneManager.onFrameRendered = () => stats.update();

---

Where each property goes now

flowchart LR
  subgraph REBUILD["needs new buffers"]
    d1["lineWidth"] --> m4["reset + redraw"]
    d2["lineHeight"] --> m4
    d3["extrusionWidth"] --> m4
    d4["renderTubes"] --> m4
  end

  subgraph CHEAP["in place"]
    c1["extrusionColor"] --> m2["material uniform"]
    c2["travelColor"] --> m2
    c3["ambientLight"] --> m2
    c4["directionalLight"] --> m2
    c5["brightness"] --> m2
    c6["startLayer"] --> m3["clipping planes"]
    c7["endLayer"] --> m3
    c8["singleLayerMode"] --> m3
  end

  subgraph FREE["free"]
    r1["renderTravel"] --> m1["group.visible"]
    r2["renderExtrusion"] --> m1
  end

  style FREE fill:#1a5c2e,color:#fff
  style CHEAP fill:#7a5c00,color:#fff
  style REBUILD fill:#8b1a1a,color:#fff

Loading

---

Toggling travels

sequenceDiagram
  autonumber
  participant U as caller
  participant S as SceneManager
  participant O as ObjectsManager
  participant G as scene graph

  rect rgb(60, 20, 20)
  note over U,G: PR 310
  U->>S: renderTravel = false
  S->>S: emit + debounce
  S->>O: resetScene()
  O->>G: discard everything
  S->>O: rebuild 7023 paths
  end

  rect rgb(20, 50, 30)
  note over U,G: PR 311
  U->>S: renderTravel = false
  S->>O: setTravelsVisible(false)
  O->>G: travelMovesGroup.visible = false
  note over G: geometry kept,<br/>re-enable is free
  end

Loading

---

Verified in the browser

3DBenchy, 7023 paths, driven through the real API:

action	result
travel toggle on/off/on	same uuid, extrusions untouched
extrusionColor	same uuid, uniform → 00ff00
travelColor	same uuid, colour → ff00ff
endLayer = 80	same uuid, clipMaxY = 24, model visibly clipped
renderTubes	BatchedMesh ⇄ LineSegments2, rebuilt — as intended

---

Bugs this surfaced

• createClippingPlanes(lineWidth, lineHeight) was passing dimensions where a layer range belonged
• Every rerender appended an empty LineSegments2 and leaked its material
• renderPathsAsTubes pushed a new material per progressive frame instead of caching one per tool
• renderPathIndex indexes job.paths but was slicing job.travels, so re-enabling travels after a completed render drew nothing
• clear() left the old ObjectsManager in disposables, double-disposing it
• Rebuilt tube materials lost the layer range

And found in review, fixed on this branch:

• The global color-keyed material cache aliased same-color tools and resurrected disposed materials — removed (it was also the blocker SceneManager never disposes its geometries: every render leaks a full model #375 identifies for safe disposal)
• clear() reset renderTubes and the lighting to defaults for the next job
• An unset start layer baked NaN into every clipping plane and clip uniform (undefined behavior in GLSL)
• A scalar extrusionColor only recolored tool 0
• devMode created two DevGUIs: the constructor duplicated the setter's initGui()
• renderAnimated()'s completion promise was not propagated by processGCode / processGCodeStream

---

Numbers

	before	after
SceneManagerEvent members	23	0 — enum deleted
emit() calls	19	0
EventsDispatcher	1 class + bus	deleted
scene-manager.ts (vs develop)	1075 lines	904
tests (vs develop)	266	355
coverage of new code	23%	100%

---

Still open

• Build volume and bounding box aren't moved into the manager yet — done in Move the build volume and bounding box into the ObjectsManager #380, stacked on this PR
• renderPathIndex still conflates paths / travels / toolPaths in renderAnimated
• Progressive rendering still leaves per-frame chunks in the scene (Progressive rendering leaves the scene fragmented into per-frame chunks #355) — and with rebuilds now rare, they persist until a dimension property changes
• topLayerColor, lastSegmentColor and disableGradient are still stored but never read (topLayerColor, lastSegmentColor, toolColors and disableGradient are accepted but never used by the renderer #356)
• Travel moves above the top layer are still clipped (Travel lines are clipped #278) — fixed here: a layer bound at the very end of the stack no longer produces a clipping plane

Assisted by Claude Code - Opus 5

[github-actions]

Visit the preview URL for this PR (updated for commit 383531c):

https://gcode-preview--pr311-objects-manager-5lxp4zs4.web.app

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[remcoder]

In terms of scope:

• let's leave topLayerColor, lastSegmentColor, toolColors and disableGradient are accepted but never used by the renderer #356 out his. Low prio for me
• I'd vote to leave Progressive rendering leaves the scene fragmented into per-frame chunks #355 out too for now.. to keep things simple. let's stabilze first

[remcoder]

@sophiedeziel
btw, let's do some test before merging. I'm thinking off:

• large model test
• perf regression test
• slow computer / mobile test
• the frame components ( react / vue / svelte) should be tested, for lifecycle test
• mem leak test
  anything else?
  Maybe some are already done?

[sophiedeziel]

perf regression test

I measured yesterday, we actually have a performance gain with fewer re-renders, and some re-renders that start at some point of the flow instead of doing a whole round trip