Game Loop simulation in Golang

I want to create game loop in go(lang), so i tried this:

package main

import (
	"fmt"
	// "runtime"
	"sync"
	"time"
)

var v = 0
var wg sync.WaitGroup
var sec = 5

func main() {
	wg.Add(1)
	gameLoop()
	wg.Wait()
}

func gameLoop() {
	time.AfterFunc(16*time.Millisecond, gameLoop)
	v++
	fmt.Println(v)
	if v == sec*60 {
        // fmt.Println("Goroutines: ", runtime.NumGoroutine())
		panic("err")
		wg.Done()
	}
}

This program running at 62.5Hz (16*time.Millisecond), var sec is used for calling wg.Done() after 5 second and caused var v printed 300 times.

calling panic("err") making the result like this:

panic: err

goroutine 314 [running]:
panic(0x493c60, 0xc420094370)
	/usr/local/go/src/runtime/panic.go:500 +0x1a1
main.gameLoop()
	/home/billyzaelani/Desktop/main.go:26 +0x11f
created by time.goFunc
	/usr/local/go/src/time/sleep.go:154 +0x44
exit status 2

Well what is the meaning of goroutine 314 [running] ? did i use 314 goroutine for 5 second game loop? how if this run for hours?

But, if the program use runtime package and print runtime.NumGoroutine which is return number of goroutine, the result is Goroutines: 2

So, back again what is the meaning of goroutine 314 [running]? while runtime package say different things.

Last one, if anyone can show me the better way to create game loop in golang, i really appreciate that, thankyou

AfterFunc executes the registered function in a goroutine. https://golang.org/pkg/time/#AfterFunc

While there are only 2 go routines running at a time, there have been 314 (maybe?? Not sure how goroutine ids work) goroutines throughout the program.

i don't consider it a "better" way, but a different way, and my preferred, could be to model the game loop as a for loop.

func gameLoop()  {
	tick := time.Tick(16 * time.Millisecond)

	for {
		select {
		case <-tick:

		}
	}
}

In addition to concisely registering a case for an interval, selecting over a channel allows you to easily model a timeout, by adding another case for <-time.After, or for cancellation, by adding another case for a <-done channel.