Game Development Reference
In-Depth Information
Loops
Loops are extremely useful when it comes to performing tasks such as checking large
amounts of data or checking a function multiple times. GameMaker has four loops avail-
able for use. Let's start simple, shall we?
The repeat loop
The simplest loop in GameMaker would have to be the
repeat
loop. The
repeat
loop
does exactly what it says; it repeats.
The
repeat
loop will repeat any code in curly braces that follow it the number of times
defined by the programmer. Here is a screenshot of how this looks:
The code in the preceding screenshot is a bit more complex than the previous example, but
what it does is simple.
It starts by initializing a local variable named
xx
. It sets this variable value to
0
.
It then moves into the
repeat
statement. You can see number
10
in brackets to the right
of it. This means the code within the curly braces will be repeated 10 times.
The first line in the curly braces creates a new object named
obj
at position
xx,y
in the
room. Remember that
xx
is equal to
0
at the first run, so the final position is
0,y
.
y
is a
built-in variable that holds the object's current
y
position in the room.
The next line adds
32
to the
xx
variable. On first run, this would make
xx
equal to
32
; on
the second run
xx
would become 64, and so on.
The preceding code will create 10 objects in a line from left to right.
