Designing Games with Game Maker - YoYo Games

instance_count* Number of instances that currently exist in the room.
instance_id[0..n-1]* The id of the particular instance. Here n is the
number of instance.
Note that the assignment of the instances to the instance id's changes every step so you
cannot use values from previous steps. Let me give an example. Assume each unit in your
game has a particular power and you want to locate the strongest one, you could use the
following code:
{
}
maxid = -1;
maxpower = 0;
for (i=0; i maxpower)
{maxid = iii; maxpower = iii.power;}
After the loop maxid will contain the id of the unit with largest power. (Don't destroy instances
during such a loop because they will automatically be removed from the array and as a result
you will start skipping instances.)
instance_find(obj,n) Returns the id of the (n+1)'th instance of type obj.
obj can be an object or the keyword all. If it does not exist, the special object
noone is returned. Note that the assignment of the instances to the instance
id's changes every step so you cannot use values from previous steps.
instance_exists(obj) Returns whether an instance of type obj exists. obj
can be an object, an instance id, or the keyword all.
instance_number(obj) Returns the number of instances of type obj. obj
can be an object or the keyword all.