Fast enter playmode support by sim-bz · Pull Request #1098 · Unity-Technologies/com.unity.cinemachine

sim-bz · 2026-02-12T21:03:45Z

Purpose of this PR

https://jira.unity3d.com/browse/UUM-131015

Static variable management in Cinemachine to support fast enter playmode.

We'll need to add exceptions for

CinemachineFreeLook CreateRigOverride and DestroyRigOverride (because of static responders in CinemachineFreeLookEditor).
CinemachineVirtualCamera CreatePipelineOverride and DestroyPipelineOverride (because of static responders in CinemachineVirtualCameraEditor).
CinemachineCore CameraUpdatedEvent and CameraActivatedEvent (because of static responders in CinemachineVolumeSettings).

Testing status

[Explanation of what’s tested, how tested and existing or new automation tests. Can include manual testing by self and/or QA. Specify test plans. Rarely acceptable to have no testing.]

Added an automated test
Passed all automated tests
Manually tested

Documentation status

[Overview of how documentation is affected by this change. If there is no effect on documentation, explain why. Otherwise, state which sections are changed and why.]

Updated CHANGELOG
Updated README (if applicable)
Commented all public classes, properties, and methods
Updated user documentation

Technical risk

[Overall product level assessment of risk of change. Need technical risk & halo effect.]

Comments to reviewers

[Info per person for what to focus on, or historical info to understand who have previously reviewed and coverage. Help them get context.]

Package version

[Justification for updating either the patch, minor, or major version according to the semantic versioning rules]

Updated package version

richardk-u3d · 2026-02-13T09:48:01Z

com.unity.cinemachine/Runtime/Behaviours/CinemachineDecollider.cs

+        {
+            Array.Fill(s_ColliderBuffer, null);
+            Array.Fill(s_ColliderDistanceBuffer, 0f);
+            Array.Fill(s_ColliderOrderBuffer, 0);


FYI i am fixing the analyzer to consider calls to Array.Fill as successful initialization

These don't need to be initialized at all, as they are just scratch buffers. I would have disabled the warning here.

com.unity.cinemachine/Runtime/Core/UpdateTracker.cs

com.unity.cinemachine/Runtime/Deprecated/CinemachineFreeLook.cs

richardk-u3d

some commented out bits im not sure about, but overall looks good

richardk-u3d

need to figure out if having 2 RuntimeInitializeOnLoadMethod's is something we want to allow. the analyzer gets confised by it.

u-pr · 2026-02-17T15:53:54Z

PR Reviewer Guide 🔍

Here are some key observations to aid the review process:

🎫 Ticket compliance analysis ✅ UUM-131015 - Fully compliant Compliant requirements: Implemented 'ResetStaticsOnLoad' with '[RuntimeInitializeOnLoadMethod]' across the codebase for identified classes (CinemachineCore, CinemachineDebug, CinemachineBlend, etc.). Handled Editor-specific static resets (FreeLookEditor, VirtualCameraEditor). Converted some statics to readonly or instance members where appropriate (CameraState, CinemachineOrbitalTransposer). Handled exceptions for CinemachineCore events as noted in the PR description.
⏱️ Estimated effort to review: 3 🔵🔵🔵⚪⚪ The PR touches many files with a repetitive pattern to handle static resets, requiring verification of initialization logic and potential race conditions across Editor and Runtime assemblies.
🏅 Score: 92 The PR systematically addresses the Fast Enter Play Mode requirements with appropriate resets and architectural changes. A potential race condition in debug settings initialization prevents a perfect score.
🧪 No relevant tests
🔒 No security concerns identified
⚡ Recommended focus areas for review Possible Race Condition In `CinemachineDebug.ResetStaticsOnLoad`, `GameViewGuidesEnabled` is set to `false`. However, in `CinemachineCorePrefs.ResetStaticsOnLoad` (Editor), it is set to `ShowInGameGuides.Value`. Since both methods are decorated with `[RuntimeInitializeOnLoadMethod]`, their execution order is undefined. If `CinemachineDebug` runs last, it will overwrite the user's preference with `false`. Consider removing the assignment in `CinemachineDebug` if the Editor script handles it, or consolidating the logic. GameViewGuidesEnabled = false;
Update review

🤖 Helpful? Please react with 👍/👎 | Questions❓Please reach out in Slack #ask-u-pr

u-pr · 2026-02-17T15:56:57Z

PR Code Suggestions ✨

🤖 Helpful? Please react with 👍/👎 | Questions❓Please reach out in Slack #ask-u-pr

glabute · 2026-02-23T17:06:51Z

com.unity.cinemachine/Runtime/Behaviours/CinemachineDecollider.cs

+        {
+            Array.Fill(s_ColliderBuffer, null);
+            Array.Fill(s_ColliderDistanceBuffer, 0f);
+            Array.Fill(s_ColliderOrderBuffer, 0);


These don't need to be initialized at all, as they are just scratch buffers. I would have disabled the warning here.

glabute · 2026-02-23T17:10:32Z

com.unity.cinemachine/Runtime/Behaviours/CinemachineStoryboard.cs

+        [RuntimeInitializeOnLoadMethod]
+        private static void ResetStaticsOnLoad()
+        {
+            s_StoryboardGlobalMute = false;


We don't want to be resetting this on domain reload. It's value should be taken from CinemachineCorePrefs.StoryboardGlobalMute.Value

glabute · 2026-02-23T17:15:52Z

com.unity.cinemachine/Runtime/Core/Predictor.cs

+            [RuntimeInitializeOnLoadMethod]
+            private static void ResetStaticsOnLoad()
+            {
+                Array.Fill(s_Buffer, 0f);


no need to fill the buffer with anything

Yes, I know they are scratch buffers, but it's preferable to zero-out/clear dangling information from scratch buffers than to add an exception for these imho ... @richardk-u3d Do you have any feedback for these use cases?

If they really do not need clearing, I suppose we are wasting performance/hurting enter playmode time by clearing them. If that's the case, I would suppress the warning instead. (though it's your call - you are the owners/area experts)

If you choose to suppress the warning instead, please just include a comment explaining why it does not need resetting, so it's obvious for future readers.

glabute · 2026-02-23T17:17:01Z

com.unity.cinemachine/Runtime/Core/RuntimeUtility.cs

+            Array.Fill(s_HitBuffer, default);
+            Array.Fill(s_PenetrationIndexBuffer, 0);


No need to fill these buffers

As with the other cases of "you dont need to", if you change this to suppress the warning, it would be good to include a comment saying why it does not need resetting.

glabute · 2026-02-23T17:18:59Z

com.unity.cinemachine/Runtime/Debug/CinemachineDebug.cs

+        {
+            s_AvailableStringBuilders = null;
+            OnGUIHandlers = null;
+            GameViewGuidesEnabled = false;


Should be initialized to CinemachineCorePrefs.ShowInGameGuides.Value

glabute · 2026-02-23T17:19:52Z

com.unity.cinemachine/Runtime/Deprecated/CinemachineCollider.cs

+        [RuntimeInitializeOnLoadMethod]
+        private static void ResetStaticsOnLoad()
+        {
+            Array.Fill(s_ColliderBuffer, null);


not needed, unless having stale Collider pointers upsets c# and unity

sim-bz added 4 commits January 21, 2026 16:58

Added support for fast enter play mode to some static variables.

42f865a

Fixed typo..

2859633

Added more support for ResetStaticsOnLoad.

d419851

Cleanup and more exceptions.

aa8e5b2

sim-bz requested a review from richardk-u3d February 12, 2026 21:04

richardk-u3d reviewed Feb 13, 2026

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com.unity.cinemachine/Runtime/Core/UpdateTracker.cs Show resolved Hide resolved

richardk-u3d reviewed Feb 13, 2026

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com.unity.cinemachine/Runtime/Deprecated/CinemachineFreeLook.cs Outdated Show resolved Hide resolved

richardk-u3d approved these changes Feb 13, 2026

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richardk-u3d suggested changes Feb 13, 2026

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Added pragma disabled UDR0001 for problematic static events.

ba15796

sim-bz marked this pull request as ready for review February 17, 2026 15:51

sim-bz requested a review from glabute as a code owner February 17, 2026 15:51

Merge branch 'main' into uum-131015

d7d180a

Updated version and changelog.

58a29e7

sim-bz requested a review from sebastienduverne as a code owner February 17, 2026 15:55

sim-bz requested a review from richardk-u3d February 17, 2026 18:02

glabute requested changes Feb 23, 2026

View reviewed changes

		Array.Fill(s_HitBuffer, default);
		Array.Fill(s_PenetrationIndexBuffer, 0);

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sim-bz commented Feb 12, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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u-pr bot commented Feb 17, 2026

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u-pr bot commented Feb 17, 2026

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sim-bz commented Feb 12, 2026 •

edited

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