How to use getCharactersAt

[sbernardotti]

Hi everyone, I need to check if there is a player in determined position

What I found is the funcion getCharactersAt which receives 2 parameters: position (x, y) and layer (string).

The problem is that I always receive an empty array. Here is the test code:

//////
//////
this.gridEngine.addCharacter({
      id: "player",
      container: playerContainer,
      speed: 4.1,
      charLayer:"charlayer"
});

this.gridEngine.setPosition("player", { x: 50, y: 50 });

const checkFunc = this.gridEngine.getCharactersAt({ x: 50, y: 50 }, "charlayer");

// Expected: ["player"]
// Returns: []

//////
//////

Thank you!

[Annoraaq]

I think in your case the problem is that you omit the charLayer argument of setPosition. Therefore it defaults to undefined. So you position the character to charLayer undefined.
Change it to
this.gridEngine.setPosition("player", { x: 50, y: 50 }, "charLayer");
and it should work.

Now that I see it, I must say that I can understand the confusion here. It is not very intuitive that the char layer is also changed if you do not pass it.

I think a reason for this was compatibility for tilemaps without char layers. If no char layers are specified in a tile map, the uppermost layer that does not have the ge_alwaysTop property is selected as the default char layer, called undefined.
And it is an optional parameter because of backwards compatibility with GridEngine versions that did not support char layers.

One alternative would be to change setPosition in a way, that it does not change the char layer at all, if it is set to undefined.
But since this is a backwards compatibility breaking change, I will postpone it to version 3 of GridEngine.

However, I will update the docs, so that it is explicit that the layer undefined is set, if the parameter is omitted.