[TF2] Orphaned weapon unusual particles flooding screen (with repro info)

[rabscootle]

REPRO INFO:

Repro video: https://www.youtube.com/watch?v=7x6cGcLR38c

1. Load into a map with sv_cheats set to '1'
2. Spawn in bot players ('tf_bot_add')
3. Enable friendly fire (mp_friendly_fire '1')
4. Die while holding out Unusual-quality weapon and spectate player in third-person view*
5. Kill player you are spectating (i.e. 'bot_whack' command)
6. Switch to first-person and then third-person (default key Spacebar) before Spectate switches to another player and/or player respawns

• The spectator view does not necessarily change much aside from maybe requiring to press space bar one more time

---

All unusual weapon effects (Hot, Cool, Isotope, Energy Orb) currently have an issue where they can indefinitely flood a user's screen upon spawning in (and while spectating players). This particle stays on the user's screen until they switch to a weapon with the matching effect and swap off of it. Depending on the weapons a player owns/uses, this bug can occur enough times for it to be considered a disadvantage of owning Unusual-quality weapons.

[MostlyBags]

Was there ever a fix for this?

[CipherlockYT]

I managed to put together a community fix for the orphaned weapon unusual particle issue. This fix currently applies to Energy Orb (due to it being the worst offender and the least amount of particle systems), but the same approach can be extended to other weapon unusuals once I have the time.

Here is the workshop link to the community fix (note: the community fix also includes custom particle systems for each warpaintable weapon so that the unusual effect can safely be reimplemented into the weapon unusual pool, but I split up the files so Valve can choose to ignore that): https://steamcommunity.com/sharedfiles/filedetails/?id=3561477398

How It's Done
The fix is strictly particle system based and does not rely on code changes. Due to it just being a .pcf replacement, it should be quite simple to implement. In the .pcf, every particle system using "Constrain distance to path between two control points" was redone to avoid said constraint. I did this by adding a "Movement Lock to Control Point" operator with lock rotation enabled, and then added speed to "Position within Sphere" to control direction rather than using the constraint. Also had to reapply "Movement Basic".

Again, this method can be applied to the other weapon unusuals but takes a bit of time to redo each particle system.