Run code in newly created room

[Smig]

I'm getting the error:

specified layer "LayerStars" does not exist

On the following code:

var star = instance_create_layer(starX, starY, "LayerStars", oStar);

Which is part of a script (setupStarMap) that is being called from another room, like this:

room_goto(rStarMap);
setupStarMap();

If I run this code on the create event of an object that I drag and drop on the room, it works, so the layer name is correct.

I assume this is caused by that code still running on the previous room, despite it being after the room_goto instruction. Is that correct? Shouldn't it change rooms before the next line? If that's the case, is there some way to specify running it on that room? Otherwise I need a new object just to run that code.

 

[Diamond Hunter Zero]

I'm getting the error:

specified layer "LayerStars" does not exist

On the following code:

var star = instance_create_layer(starX, starY, "LayerStars", oStar);

Which is part of a script (setupStarMap) that is being called from another room, like this:

room_goto(rStarMap);
setupStarMap();

If I run this code on the create event of an object that I drag and drop on the room, it works, so the layer name is correct.

I assume this is caused by that code still running on the previous room, despite it being after the room_goto instruction. Is that correct? Shouldn't it change rooms before the next line? If that's the case, is there some way to specify running it on that room? Otherwise I need a new object just to run that code.

(I assume this code is being run in some kind of object and not a room creation event?)
When the room_goto() function is executed, Gamemaker will not move to the new room until every line of code still remaining in the event that room_goto() is inside of, has been run. This means that instance_create_layer(starX, starY, "LayerStars", oStar); will be run in the original room, where the layer doesn't exist, because setupStarMap(); is being run in the original room.

In order to run code in a newly moved-to room, you either need to write it in the new room's Creation Event or in a persistent object from the previous room. For your case, I would recommend temporarily making your calling object
persistent and have it run an alarm like this:

Inside the Original Room & Object

room_goto(rStarMap);
persistent = true;
alarm[0] = 1;

Inside the Alarm 0 Event of the calling object

var star = instance_create(starX, starY, "LayerStars", oStar);
instance_destroy();

 

[Nocturne]

Calling room_goto does not immediately change rooms. It will change room when the END of the code block is reached, so the setup script is still being called in the previous room. You can fix that by using the functions to target another room in the setup script. Look at this page of the manual for more information: https://docs2.yoyogames.com/index.html?page=source/_build/3_scripting/4_gml_reference/rooms/layers/layer_set_target_room.html