Error on enableing physics

Phaser 3
1

Hello there !
I’m making a multiplayer game and I want to change the player scene.
When I change the scene, I can’t re-enable the physics on that scene !!

My error occurs with this line of code.
self.physics.world.enable(self.player);
(self is the current scene)
The error : Uncaught TypeError: Cannot read property ‘enable’ of null

Thanx for your upcoming support :slight_smile:

2

What’s the stack trace (click :arrow_forward:︎)?

3

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image799×800 18.3 KB

4

Likely the scene self is shutdown at that point.

You probably need to remove that event listener when the scene stops.

6

I tried it but I’m not sure how to deal with it while it’s in a update loop. I tried several things like “if(self)” il the loop but still, doesent seems to be working.
Here is the part where I call this function:

update() {
if (this.player) {
if (this.player.x < 0) {
socket.emit(‘preQuit’);
this.scene.start(‘Scene2’);
}
}
if (this.player) {
player_gameplay(this);
}
}

7

OK, I got it.
I am using Scene.start instead of Scene.switch ! So the rigth way was :

this.scene.switch('Scene2');

Thx for helping :slight_smile:

1 Like
8

It’s working but I’m running into another issue now. What I did was just start the ‘Scene2’ while the other one was running behind it. That’s something I neet to fix bc I want the create event to fire every time I join in. Another event could work but I don’t really want to mess with that.
I just want to remove the scene (like this.scene.start(scene) does) but then I run into the physics issue…

9

Go back to scene.start(), I think.

If you’re adding event listeners in the scene create(), they need to be removed when the scene is stopped.

10

I’m not sure what type of listeners you are talking about. Socket listeners ? If so how sould I remove them ?

11

I think socket listeners, yes. Whatever is calling addOtherPlayers. How/where are you adding them?

12

So I initialise the socket one on login, then no more. I call the addOtherPlayers function whenever I join a scene. My issue is that when changing scenes, the listener on Scene1 doesent stop, even if the scene is “deleted” with “self.scene.start(Scene2)”.

13

What’s the listener on Scene1?

14

“socket.on(‘newPlayer’, …)”
It’s fired whenever a player logs in, or switch scenes

15

Can you show the code for that?

16

Server-side:

socket.on('changeMap', (data) => {
  socket.emit('currentPlayers', player);
});

where player[someId] is an object containing all player info.

Client-side:

create(){
  // sending to server the "current" map
  socket.emit('changeMap', idOfMap);

  // if player is yourself, then addPlayer() 
  socket.on('currentPlayers', function (players) {
    Object.keys(players).forEach(function (id) {
      if (players[id].playerId === socket.id) {
        addPlayer(self, players[id]);
      }else if(players[id].currentMap === currentMap){
        addOtherPlayers(self, players[id]);
      }
    });
  });
}

addPlayer() and addOtherPlayers() are basicly the same, just adding them to different containers.

17

Something like

class Scene {
  create () {
    socket.on('currentPlayers', addCurrentPlayers, self);

    this.events.once('shutdown', function () {
      socket.off('currentPlayers', addCurrentPlayers, self);
    });
  }
}
19

It works ! But now when I re-enter the First scene, the “addPlayer()” fires after the update()…

20

This topic should help if someone is running the same issue