moved 'core' to 'internal'

internal/entity/chunk.go

@@ -0,0 +1,86 @@
+package entity
+
+import (
+	"log"
+	"sync"
+)
+
+type Chunk struct {
+	Position ChunkPosition
+	Entities map[Entity]struct{}
+	lock     sync.Mutex
+}
+
+func NewChunk(position ChunkPosition) *Chunk {
+	return &Chunk{
+		Position: position,
+		Entities: make(map[Entity]struct{}),
+	}
+}
+
+func (c *Chunk) AddEntity(entity Entity) {
+	c.Entities[entity] = struct{}{}
+}
+
+func (c *Chunk) RemoveEntity(entity Entity) {
+	delete(c.Entities, entity)
+}
+
+// send packet to all peers in this chunk and kill each peer if error
+func (c *Chunk) SendPacket(typeID uint32, pkt ...interface{}) {
+	c.SendPacketExclude(nil, typeID, pkt...)
+}
+
+func (c *Chunk) SendPacketExclude(exclude Entity, typeID uint32, pkt ...interface{}) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+
+	for entity := range c.Entities {
+		// only send to players, and exclude the player that sent the packet
+		if entity.GetKind() != ENTITY_KIND_PLAYER || entity == exclude {
+			continue
+		}
+
+		plr, ok := entity.(*Player)
+		if !ok {
+			log.Panic("Chunk.SendPacket: entity kind was player, but is not a *Player")
+		}
+		peer := plr.Peer
+
+		if err := peer.Send(typeID, pkt...); err != nil {
+			log.Printf("Error sending packet to peer %p: %v", peer, err)
+			peer.Kill()
+		}
+	}
+}
+
+func (c *Chunk) GetAdjacentPositions() []ChunkPosition {
+	return []ChunkPosition{
+		{c.Position.X - 1, c.Position.Y - 1},
+		{c.Position.X - 1, c.Position.Y},
+		{c.Position.X - 1, c.Position.Y + 1},
+		{c.Position.X, c.Position.Y - 1},
+		{c.Position.X, c.Position.Y},
+		{c.Position.X, c.Position.Y + 1},
+		{c.Position.X + 1, c.Position.Y - 1},
+		{c.Position.X + 1, c.Position.Y},
+		{c.Position.X + 1, c.Position.Y + 1},
+	}
+}
+
+// https://stackoverflow.com/a/45428032 lol
+func ChunkSliceDifference(a, b []*Chunk) []*Chunk {
+	m := make(map[*Chunk]struct{})
+	for _, item := range b {
+		m[item] = struct{}{}
+	}
+
+	var diff []*Chunk
+	for _, item := range a {
+		if _, ok := m[item]; !ok {
+			diff = append(diff, item)
+		}
+	}
+
+	return diff
+}