perf: Track mounted pointer-event handlers so hit tests can early-out - #3982
perf: Track mounted pointer-event handlers so hit tests can early-out#3982spydon wants to merge 1 commit into
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| @internal | ||
| void adjustPointerEventHandlerCount(int delta) { | ||
| _pointerEventHandlerCount += delta; | ||
| assert(_pointerEventHandlerCount >= 0); |
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it might not be very actionable but can we still add a message
| void onMount() { | ||
| super.onMount(); | ||
| DoubleTapDispatcher.addDispatcher(this); | ||
| findRootGame()?.adjustPointerEventHandlerCount(1); |
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is the extra recursive findRootGame() on every mount/unmount worth the optmization?
luanpotter
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luanpotter
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I am again concerned with the complexity, ad-hoc-ness, and brittleness of these static/global caches and counters, that could lead to impossible to find bugs of undelivered events due to de-syncs. what if a component is removed w/o being mounted due to some edge-case, and then suddenly events stop working reliably.
I am again tempted to think more holistically, do we even need this, can't games just always return true on hitTestSelf within bounds? do we need to make this distinction of games without tap components being touch transparent, I didn't even know that was the case and doesn't feel intuitive. we also used to have and require the game-level mixins, which might be a good alternative, yes a bit more work for the user but more explicit and clear, less error-prone. or just an overridable config to make the game transparent (default false).
is there really an use case for a game that dynamically changes its tap transparency based on current components that we need to bake into the engine?
this also mixes concerns about event delivery even more into the game class instead of the dispatchers, but I am ok with that part as I might be refactoring it again once I remove all the old detectors. right now it is quite the mess already imo.
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Description
The root game now counts mounted components that can receive pointer events (
TapCallbacks,DragCallbacks,DoubleTapCallbacks,ScaleCallbacks,SecondaryTapCallbacks), socontainsEventHandlerAt, which Flutter calls on every hit test, returns immediately without walking the component tree for games without any pointer-event handlers.Extracted from #3960 so the data-structure change there stands alone (as requested in this comment). Stacked on #3981.
Checklist
docsand added dartdoc comments with///.examplesordocs.Breaking Change?
Related Issues
Relates to #3957