Rules Governing Local & Global Code - A Definitive Summa

[plinydogg]

Hi everyone! I don't have much GE time right now but I wanted to post about a topic that keeps giving me a lot of trouble: what EXACT rules govern the interaction between local and global code (and local and global variables)?

I think the following are correct (but am not sure):

(1) Global variables can be manipulated by any actor;

(2) Local variables (i.e., actor variables) cannot be modified by modified by global code (?).

(3) Actor variables cannot be modified by other actors (?).

For example, let's say you have a "cup" actor that contains a local variable called "drops" which represents the amount of water (measured in drops) contained in the cup. Periodically, you might want to send another "drop" to the "cup" and add to the water in the cup (i.e., change the value of cup's local variable "drops"). If my statement in (3) is correct, then you could NOT do the following:

In the drop actor, on collision with "cup"->script editor:
cup->drops++;

Instead you would have to change the "drops" variable with some sort of action taken by the cup actor itself (because an actor, drop, cannot modify another actor's local variables). Something like this would then work:

In the cup actor, on collision with "drop"->script editor:
drops++;

I hope this makes sense.

I would really appreciate it if someone would write a definitive statement of these rules, being as specific as possible.

Take care!

Plinydogg

[makslane]

You can change the actor variables from global code and other actors.
But the actors variables defined by Game Editor (like x, y, xscreen, yscreen, ...) can't be changed in global code.

[plinydogg]

Oh! That is very useful information! Thanks Makslane. If you think of anything else later, please post it here.

[plinydogg]

A follow up question: when you say that actor variables defined by Game Editor can't be changed in global code does this include actor "states" (if that is the right word), such as local actor visibility states? Or is it only variables?

Thanks!

[makslane]

When you change the value of x, for example, after script execution, Game Editor need call a funcion after detect the change.
This change detection can be done in global code, yet.

There is no problem with other variables, like defined in the games.