ue4 data model

GameInstance (an object spawned when you launch the application and that remains the same until you close it)
GameMode (spawned when a level is loaded)
GameState (spawned by the gameMode)
PlayerState (spawned when a PlayerController is spawned = when a player arrives in the game)
You have to pay close attention to what you do and where you do it
when coding a multiplayer game. When it comes to singleplayer, you can’t
really “have it wrong” except for GameInstance stuff.
But here are the general guidelines I follow:
GameInstance - Holds any non-pointer persistent
variables (persistent means that you need to store in between two levels
and that you don’t need to store in a SaveGame)
GameMode - The overall game manager - starts and
stops the current game space you’re in, handles the GameStates and how
they rotate - an example might be “King of the Hill”
GameState - Keeps track of every data relative to
the current state of the game (timers, scores, winning team) that all
players in the game need to know about, handles scripted events related
to the state
For instance:
PregameState: Prevents player from performing any action, starts a timer
and display it to everyone. When timer expires, ask KotH (KingOfTheHill
game mode) to rotate to IngameState
IngameState: Enable player input, spawn a big loud noise and open
players’ spawn gates. Open the Capture Point and store the amount of
capture time both teams have. When one of the team reaches max score,
asks KotH to switch to EndgameState.
EndgameState: Destroy every player’s characters and starts a cinematic
showing the PlayOfTheGame then asks KotH to rotate to ScoreGameState
etc.
PlayerController - HUD, Camera, Mouse, Keyboard, Gamepad, Inputs calling actions on the Character.
PlayerCharacter - Actions in response of
Controller’s input + Holds personal infos and stats (Health, Ammo - but
Ammo might on your Weapon Class if you can switch Weapons).
PlayerState - Holds every variable non related to
the PlayerCharacter that needs to be known by everyone (best scores,
current killing streak, player name…).