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Improper slingloading locality causes load drops on desync
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Description

A3 doesn't enforce slingloaded crates' locality to be the same as the vehicle doing the slingloading. The result is that any desync results in the load getting too far from the helo, and ultimately that the load drops from the helo.

Details

Severity
Major
Resolution
Open
Reproducibility
Always
Operating System
Windows 10 x64
Operating System Version
Windows 10 Pro 64-bit (10.0, Build 16299)
Category
Sling Loading
Steps To Reproduce
  1. Run up a remote dedicated server instance.
  2. Run up a client and connect to the dedicated server.
  3. Create a crate which is local to the dedicated server (owner crate = 2, as eval'd server side).
  4. Initiate slingloading on the crate, note that the owner of the crate does not change.
  5. Put the helicopter in a normal flight profile, with some reasonable (100kph+) horizontal speed.

<outside the game>

  1. Using some software like clumsy, emulate packet loss between the client and server. 6a. I find the best way to repro the issue is by setting packet loss to 100% for a second or so. 6b. After about a second of 100% packet loss, the load will unhook from the helicopter 6 note. This PL actually has to apply to the server<->client connection, it may be hard to test on a LAN unless you actually do things correctly
  1. Perform steps 1 through 5, but then use setOwner server side in order to enforce the owner of the crate to be the client rather than the server
  2. Perform step 6 again. You'll note that you can fully desync from the server for any length of time and the load will not drop from the helo.
Additional Information

The upshot of this is that slingloading is completely unreliable in any large scale gameplay. The fix that we implemented in SQF involved simply hooking in to the events for slingloading and ensuring that they kick the ownership of the slingloaded crate over to the correct client when slingloading is initiated. This should be done at the engine level to avoid hacky solutions like we've implemented. They should also account for helicopter ownership changes that can occur when pilots/copilots swap control of the helicopter.

Event Timeline

batboyx2 created this task.Apr 24 2018, 3:32 AM
dedmen added a subscriber: dedmen.Wed, Mar 18, 9:27 AM

viable fix would be to change locality of the attached object to helicopter locality. BUT, that won't work for slingloaded vehicles with a driver in them, as they are local to the driver.

Can confirm, been using an in-house solution that does exactly that for about two years now. It does indeed not work for slingloaded vehicles that have a driver, for the reason you stated.