What does packet 147 stand for or where could I find up to date protocol docs?

[manfromfms]

https://tshock.readme.io/docs/multiplayer-packet-structure

[zyrafaq]

There are no up to date protocol docs. Go decompile ghe server and the client and dig into them. Feel free to DM me on discord (@zyrafaq) and I may help you.

[bartico6]

Packet 147 itself

In my packet library's naming: PlayerSetLoadoutSlot (could/should be renamed to PlayerSetLoadoutId or something)
It tells the server (or client in SSC with some caveats) to switch the active loadout slot in memory.

Handler implementation is generally client-authoritative:

C2S: It's a notification of client-side change, you can't "block it", you have to manually revert the change if you want
S2C: Requires SSC, client still gets to decide if it wants to make the change or not - in particular, being considered crowd-controlled (silence, petrify, etc.) can cause the client to ignore the server's loadout change.

Its structure is:

struct PlayerSetActiveLoadout {
    byte UserId;
    byte LoadoutId;
    ushort AccessoryVisibility;
}

where UserId is the player index it applies to, LoadoutId is the loadout ID (0-2 both sides inclusive), and AccessoryVisibility is a bitfield that is applied to bool[] Player.hideVisibleAccessory

Protocol documentation

Largely outdated & rarely updated, recommend getting familiar with Terraria.NetMessage and Terraria.MessageBuffer as they're easy to decompile & will always be up to date. I occasionally edit the docs if I spot something being out of date and have time/interest in making a change - but I'm not the owner of tShock, Pryaxis etc. at all, so I don't represent the project's attitude to changes.