Overview
The Game State API provides the core data structures for managing the GRPG server state, including players, NPCs, objects, and world data.
Game Struct
The Game struct is the central state container for the server.
type Game struct {
Players map[*Player]struct{}
Connections map[net.Conn]*Player
MaxX uint32
MaxY uint32
Database *sql.DB
TrackedObjs map[util.Vector2I]*GameObj
TrackedNpcs map[util.Vector2I]*GameNpc
Mu sync.RWMutex
CollisionMap map[util.Vector2I]struct{}
Objs map[util.Vector2I]struct{}
TimedScripts map[uint32][]func()
NpcMoves map[util.Vector2I][][]NpcMove
CurrentTick uint32
}
Fields
Set of all currently connected players
Maps network connections to player instances
Maximum X coordinate of the game world
Maximum Y coordinate of the game world
Database connection for persistent storage
TrackedObjs
map[util.Vector2I]*GameObj
Map of position to game objects (trees, rocks, bushes, etc.)
TrackedNpcs
map[util.Vector2I]*GameNpc
Map of position to NPCs in the world
Read-write mutex for thread-safe game state access
CollisionMap
map[util.Vector2I]struct{}
Positions that block player movement
Objs
map[util.Vector2I]struct{}
Set of all object positions (currently overlaps with CollisionMap)
Scripts scheduled to run at specific game ticks
NpcMoves
map[util.Vector2I][][]NpcMove
Queued NPC movement paths organized by chunk
Current game tick counter
Player Struct
Represents a player character in the game world.
type Player struct {
Pos util.Vector2I
ChunkPos util.Vector2I
Facing Direction
Inventory Inventory
Name string
DialogueQueue DialogueQueue
Skills map[Skill]*SkillInfo
Conn net.Conn
}
Fields
Player’s current world position (tile coordinates)
Current chunk the player is in (Pos / 16)
Direction the player is facing (UP, RIGHT, DOWN, LEFT)
Player’s inventory (24 slots)
Queue of dialogue messages for NPC conversations
Player’s skill levels and experience points
Network connection to the player’s client
Methods
LoadFromDB
func (p *Player) LoadFromDB(db *sql.DB) error
SaveToDB
func (p *Player) SaveToDB(db *sql.DB) error
GetFacingCoord
func (p *Player) GetFacingCoord() util.Vector2I
AddXp
func (p *Player) AddXp(skill Skill, xpAmount uint32)
The skill to add XP to (e.g., Foraging)
Amount of XP to add (capped at MAX_XP)
Supporting Types
GameObj
Represents an interactive object in the world.
type GameObj struct {
ObjData grpgobj.Obj
ChunkPos util.Vector2I
State byte
}
Static object data (ID, sprite, etc.)
Chunk containing this object
Dynamic state value (e.g., 0 = berry bush empty, 1 = has berries)
GameNpc
Represents an NPC in the world.
type GameNpc struct {
Pos util.Vector2I
NpcData *grpgnpc.Npc
ChunkPos util.Vector2I
WanderRange uint8
}
Static NPC data (ID, sprite, name, etc.)
How many tiles the NPC can wander from spawn point
Inventory
Player inventory with 24 slots.
type Inventory struct {
Items [24]InventoryItem
}
type InventoryItem struct {
ItemId uint16
Count uint16
Dirty bool
}
AddItem
func (i *Inventory) AddItem(itemId uint16)
SkillInfo
Tracks a player’s level and XP for a specific skill.
type SkillInfo struct {
Level uint8
XP uint32
}
Foraging - Gathering berries and other resources
DialogueQueue
Manages NPC conversation state.
type DialogueQueue struct {
Index uint16
MaxIndex uint16
ActiveNpcId uint16
Dialogues []Dialogue
}
type Dialogue struct {
Type DialogueType // PLAYER or NPC
Content string
}
Clear
func (dq *DialogueQueue) Clear()
Direction Enum
type Direction byte
const (
UP Direction = 0
RIGHT Direction = 1
DOWN Direction = 2
LEFT Direction = 3
)
Usage Example
// Access player in packet handler
func handleSomething(game *shared.Game, player *shared.Player) {
// Get the tile the player is facing
facingPos := player.GetFacingCoord()
// Check if there's an object there
if obj, exists := game.TrackedObjs[facingPos]; exists {
// Interact with the object
obj.State = 1
}
// Add XP to player
player.AddXp(shared.Foraging, 10)
// Save player data
player.SaveToDB(game.Database)
}