player and dimension loader with ecs system

server/ecs/system.go

@@ -0,0 +1,66 @@
+package ecs
+
+import (
+	"reflect"
+)
+
+type System interface {
+	Update(w *World)
+}
+
+type funcsystem struct {
+	update func(w *World)
+}
+
+func FuncSystem(F any) System {
+	type Storage interface {
+		BitSetLike
+		GetValueAny(eid Index) any
+	}
+	f := reflect.ValueOf(F)
+	in := f.Type().NumIn()
+	argTypes := make([]reflect.Type, in)
+	needCopy := make([]bool, in)
+	for i := 0; i < in; i++ {
+		if t := f.Type().In(i); t.Kind() == reflect.Pointer {
+			argTypes[i] = t.Elem()
+		} else {
+			argTypes[i] = t
+			needCopy[i] = true
+		}
+	}
+	return &funcsystem{
+		update: func(w *World) {
+			storages := make([]Storage, in)
+			for i := 0; i < in; i++ {
+				storages[i] = w.GetResourceRaw(argTypes[i]).(Storage)
+			}
+			args := make([]reflect.Value, len(storages))
+			if len(storages) > 0 {
+				set := BitSetLike(storages[0])
+				for _, v := range storages[1:] {
+					set = set.And(v)
+				}
+				set.Range(func(eid Index) {
+					for i := range args {
+						arg := storages[i].GetValueAny(eid)
+						if arg == nil {
+							args[i] = reflect.Zero(argTypes[i])
+						} else if needCopy[i] {
+							args[i] = reflect.ValueOf(arg).Elem()
+						} else {
+							args[i] = reflect.ValueOf(arg)
+						}
+					}
+					f.Call(args)
+				})
+			} else {
+				f.Call(args)
+			}
+		},
+	}
+}
+
+func (f *funcsystem) Update(w *World) {
+	f.update(w)
+}