FIX: Navigation not being confined to multiplayer playerRoot (case 1306361). #1443
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| { | ||
| m_CanvasGroup = m_PlayerRoot.GetComponent<CanvasGroup>(); | ||
| if (m_CanvasGroup == null) | ||
| m_CanvasGroup = m_PlayerRoot.AddComponent<CanvasGroup>(); |
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Is this add free some side-effects? I assume CanvasGroup has other implications? Reading through the docs I guess this could work just fine if "part of solution" for local multiplayer UI and having two "systems" isn't a viable solution in itself to create two navigation trees that are disjoint.
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There's a range of implications and side-effects -- most importantly, it has pretty poor performance. This is more a workaround than a proper solution. Unfortunately, with the tools we have available ATM, it doesn't seem like there's a better solution for the moment. Overall, think this is part of some extensions to uGUI that are needed to support this use case properly. Most of MultiplayerEventSystem is a workaround.
| { | ||
| var index = s_MultiplayerEventSystems.IndexOfReference(this); | ||
| if (index != -1) | ||
| s_MultiplayerEventSystems.EraseAtWithCapacity(ref s_MultiplayerEventSystemCount, index); |
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In case CanvasGroup have been added by OnEnable(), should OnDisable() remove it in that case for symmetry? The user didn't intentionally added it.
Fixes 1306361 (FogBugz).
Description
When setting up a multiplayer UI using
MultiplayerEventEvent, pointer input is confined to theplayerRootof each player. However, navigation input -- itself much more relevant to multiplayer input compared to pointer input -- is allowed to escape aplayerRootand thus makes it possible for one player to move onto the UI of another player.Changes made
The navigation mechanism built into uGUI's
Selectableis not overridable or extensible. We thus cannot limit it to parts of the UI. Discussing this with @pcosgrave.This PR attempts a workaround by relying on the
CanvasGroupmechanism that allows toggling theinteractableproperty off for an entire hierarchy and thus allSelectableobjects in the hierarchy.Notes
CanvasGroupis not a fast mechanism. The underlying implementation relies onBroadcastMessageto reachSelectableobjects. Might be good enough as a stopgap but likely, we want a more lightweight mechanism to getSelectableto only pick certain UI objects.Checklist
Before review:
Changed,Fixed,Addedsections.([case %number%](https://issuetracker.unity3d.com/issues/...)).Area_CanDoX,Area_CanDoX_EvenIfYIsTheCase,Area_WhenIDoX_AndYHappens_ThisIsTheResult.During merge:
NEW: ___.FIX: ___.DOCS: ___.CHANGE: ___.RELEASE: 1.1.0-preview.3.