MantisBT - Zandronum
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IDProjectCategoryView StatusDate SubmittedLast Update
0003459Zandronum[All Projects] Bugpublic2018-08-23 07:172018-09-10 05:12
Reporterunknownna 
Assigned ToLeonard 
PriorityhighSeveritymajorReproducibilityalways
StatusresolvedResolutionfixed 
PlatformOSOS Version
Product Version3.0 
Target Version3.1Fixed in Version3.1 
Summary0003459: Prediction regression and jitter in 3.0 when landing on the ledge of bridge things
DescriptionWhile testing some of the prediction in 3.1, I noticed some weird behavior when landing on the ledge of bridge things: The client jitters for a few tics compared to 2.1.2.

It broke completely in 3.0-alpha 160131-2023, and was partially fixed in 3.0-alpha 160510-1827. From looking at the changelog, it seems that there were some prediction issues with the newer jumping behavior backported from ZDoom.
Steps To Reproduce1. zandronum -file player_bridge_desync_test_03.wad -host
2. Connect a client to the server with an emulated ping of 300.
3. Join the game. Wait for the weapon to fully raise before using the bind below (to make sure the player doesn't try to move before he's allowed to).
4. Copy-paste "+forward;+moveleft;wait 4;+jump;wait 20;-forward;-moveleft;-jump" into the console.
5. Spectate and re-join the game to reproduce the jitter again. The bind will reproduce the jitter every time.
Additional Information
TagsNo tags attached.
Relationships
related to 0000171closed Torr Samaho backport fixed and improved jumping behavior and a fix in "P_ZMovement" 
Attached Files? player_bridge_desync_test_03.wad (38,830) 2018-08-23 07:17
/tracker/file_download.php?file_id=2353&type=bug
Issue History
Date ModifiedUsernameFieldChange
2018-08-23 07:17unknownnaNew Issue
2018-08-23 07:17unknownnaFile Added: player_bridge_desync_test_03.wad
2018-08-23 07:18unknownnaRelationship addedrelated to 0000171
2018-08-26 05:52LeonardNote Added: 0019403
2018-08-26 05:52LeonardAssigned To => Leonard
2018-08-26 05:52LeonardStatusnew => needs review
2018-08-26 05:52LeonardTarget Version => 3.1
2018-08-26 17:42Torr SamahoNote Added: 0019410
2018-08-26 17:42Torr SamahoStatusneeds review => needs testing
2018-09-10 05:12unknownnaNote Added: 0019496
2018-09-10 05:12unknownnaStatusneeds testing => resolved
2018-09-10 05:12unknownnaResolutionopen => fixed
2018-09-10 05:12unknownnaFixed in Version => 3.1

Notes
(0019403)
Leonard   
2018-08-26 05:52   
Seems like the fix for 0000171 was incomplete.
The "on ground" status is used for the jumpTics variable but is only properly calculated later on meaning the client prediction would incorrectly jump on landing.

PR.
(0019410)
Torr Samaho   
2018-08-26 17:42   
Thanks! Added your PR.
(0019496)
unknownna   
2018-09-10 05:12   
This is fixed now indeed. Thank you very much, great work!