Fix culling. (#3504)

Fixes culling for cases when another user would drag shapes inside your
viewport. We weren't correctly calculating the culling status for arrows
that might be bound to those shapes and also for shapes within dragged
in groups / frames.


### Change Type

<!-- ❗ Please select a 'Scope' label ❗️ -->

- [ ] `sdk` — Changes the tldraw SDK
- [ ] `dotcom` — Changes the tldraw.com web app
- [ ] `docs` — Changes to the documentation, examples, or templates.
- [ ] `vs code` — Changes to the vscode plugin
- [x] `internal` — Does not affect user-facing stuff

<!-- ❗ Please select a 'Type' label ❗️ -->

- [x] `bugfix` — Bug fix
- [ ] `feature` — New feature
- [ ] `improvement` — Improving existing features
- [ ] `chore` — Updating dependencies, other boring stuff
- [ ] `galaxy brain` — Architectural changes
- [ ] `tests` — Changes to any test code
- [ ] `tools` — Changes to infrastructure, CI, internal scripts,
debugging tools, etc.
- [ ] `dunno` — I don't know


### Test Plan

1. Open the same room in two browsers / tabs.
2. Have some shapes that are visible in one browser, but not the other.
3. Drag these shapes so that they are visible in the other browser as
well.
4. They should correctly get unculled.
5. Do this by dragging shapes that have arrows bound to them (arrows
should uncull), groups (shapes within them should uncull), frames.

- [x] Unit Tests
- [ ] End to end tests

### Release Notes

- Fix culling.

packages/editor/src/lib/editor/derivations/notVisibleShapes.ts

@@ -1,5 +1,5 @@
-import { RESET_VALUE, computed, isUninitialized } from '@tldraw/state'
-import { TLPageId, TLShapeId, isShape, isShapeId } from '@tldraw/tlschema'
+import { computed, isUninitialized } from '@tldraw/state'
+import { TLShapeId } from '@tldraw/tlschema'
 import { Box } from '../../primitives/Box'
 import { Editor } from '../Editor'
 
@@ -21,15 +21,10 @@ function isShapeNotVisible(editor: Editor, id: TLShapeId, viewportPageBounds: Bo
  */
 export const notVisibleShapes = (editor: Editor) => {
 	const isCullingOffScreenShapes = Number.isFinite(editor.renderingBoundsMargin)
-	const shapeHistory = editor.store.query.filterHistory('shape')
-	let lastPageId: TLPageId | null = null
-	let prevViewportPageBounds: Box
 
 	function fromScratch(editor: Editor): Set<TLShapeId> {
 		const shapes = editor.getCurrentPageShapeIds()
-		lastPageId = editor.getCurrentPageId()
 		const viewportPageBounds = editor.getViewportPageBounds()
-		prevViewportPageBounds = viewportPageBounds.clone()
 		const notVisibleShapes = new Set<TLShapeId>()
 		shapes.forEach((id) => {
 			if (isShapeNotVisible(editor, id, viewportPageBounds)) {
@@ -38,68 +33,21 @@ export const notVisibleShapes = (editor: Editor) => {
 		})
 		return notVisibleShapes
 	}
-	return computed<Set<TLShapeId>>('getCulledShapes', (prevValue, lastComputedEpoch) => {
+	return computed<Set<TLShapeId>>('getCulledShapes', (prevValue) => {
 		if (!isCullingOffScreenShapes) return new Set<TLShapeId>()
 
 		if (isUninitialized(prevValue)) {
 			return fromScratch(editor)
 		}
-		const diff = shapeHistory.getDiffSince(lastComputedEpoch)
 
-		if (diff === RESET_VALUE) {
-			return fromScratch(editor)
-		}
+		const nextValue = fromScratch(editor)
 
-		const currentPageId = editor.getCurrentPageId()
-		if (lastPageId !== currentPageId) {
-			return fromScratch(editor)
-		}
-		const viewportPageBounds = editor.getViewportPageBounds()
-		if (!prevViewportPageBounds || !viewportPageBounds.equals(prevViewportPageBounds)) {
-			return fromScratch(editor)
-		}
-
-		let nextValue = null as null | Set<TLShapeId>
-		const addId = (id: TLShapeId) => {
-			// Already added
-			if (prevValue.has(id)) return
-			if (!nextValue) nextValue = new Set(prevValue)
-			nextValue.add(id)
-		}
-		const deleteId = (id: TLShapeId) => {
-			// No need to delete since it's not there
-			if (!prevValue.has(id)) return
-			if (!nextValue) nextValue = new Set(prevValue)
-			nextValue.delete(id)
-		}
-
-		for (const changes of diff) {
-			for (const record of Object.values(changes.added)) {
-				if (isShape(record)) {
-					const isCulled = isShapeNotVisible(editor, record.id, viewportPageBounds)
-					if (isCulled) {
-						addId(record.id)
-					}
-				}
-			}
-
-			for (const [_from, to] of Object.values(changes.updated)) {
-				if (isShape(to)) {
-					const isCulled = isShapeNotVisible(editor, to.id, viewportPageBounds)
-					if (isCulled) {
-						addId(to.id)
-					} else {
-						deleteId(to.id)
-					}
-				}
-			}
-			for (const id of Object.keys(changes.removed)) {
-				if (isShapeId(id)) {
-					deleteId(id)
-				}
+		if (prevValue.size !== nextValue.size) return nextValue
+		for (const prev of prevValue) {
+			if (!nextValue.has(prev)) {
+				return nextValue
 			}
 		}
-
-		return nextValue ?? prevValue
+		return prevValue
 	})
 }

packages/tldraw/src/test/getCulledShapes.test.tsx

@@ -136,3 +136,56 @@ it('correctly calculates the culled shapes when adding and deleting shapes', ()
 	const culledShapeFromScratch = editor.getCulledShapes()
 	expect(culledShapesIncremental).toEqual(culledShapeFromScratch)
 })
+
+it('works for shapes that are outside of the viewport, but are then moved inside it', () => {
+	const box1Id = createShapeId()
+	const box2Id = createShapeId()
+	const arrowId = createShapeId()
+
+	editor.createShapes([
+		{
+			id: box1Id,
+			props: { w: 100, h: 100, geo: 'rectangle' },
+			type: 'geo',
+			x: -500,
+			y: 0,
+		},
+		{
+			id: box2Id,
+			type: 'geo',
+			x: -1000,
+			y: 200,
+			props: { w: 100, h: 100, geo: 'rectangle' },
+		},
+		{
+			id: arrowId,
+			type: 'arrow',
+			props: {
+				start: {
+					type: 'binding',
+					isExact: true,
+					boundShapeId: box1Id,
+					normalizedAnchor: { x: 0.5, y: 0.5 },
+					isPrecise: false,
+				},
+				end: {
+					type: 'binding',
+					isExact: true,
+					boundShapeId: box2Id,
+					normalizedAnchor: { x: 0.5, y: 0.5 },
+					isPrecise: false,
+				},
+			},
+		},
+	])
+
+	expect(editor.getCulledShapes()).toEqual(new Set([box1Id, box2Id, arrowId]))
+
+	// Move box1 and box2 inside the viewport
+	editor.updateShapes([
+		{ id: box1Id, type: 'geo', x: 100 },
+		{ id: box2Id, type: 'geo', x: 200 },
+	])
+	// Arrow should also not be culled
+	expect(editor.getCulledShapes()).toEqual(new Set())
+})