Designing Games with Game Maker - YoYo Games

To create global variables, that are visible to all object instances, precede them with the word
global and a dot. So for example you can write:
{
}
if (global.doit)
{
}
// do something
global.doit = false;
Alternatively you can declare the variables as being global. This declaration looks as follows.
globalvar ,,, ... ;
Once this declaration has been executed, the variable is always treated as global without the
need to put the word global and a dot in front of it. It only needs to be declared once in a
piece of code that is executed. After that in all other places the variable is considered as being
global.
Sometimes you want variables only within the current piece of code or script. In this way you
avoid wasting memory and you are sure there is no naming conflict. It is also faster than using
global variables. To achieve this you must declare the variables at the beginning of the piece
of code using the keyword var. This declaration looks as follows.
var ,,, ... ;
For example, you can write:
{
var xx,yy;
xx = x+10;
yy = y+10;