Platform Beginnings: An Idea with Legs - The Game Maker's Companion: Game Development - page 30

Adding the Animation End Event to the Walking State Object
1. Click on the Add Event button and select the Other, Animation End event.
2. Include a Change Instance action ( main1 tab) that changes into obj_pod_standing and
select yes for Perform Events .
We're now very close to being able to test our character events for the first time, but before
we can do that, we're actually going to have to create another object for Fishpod. This isn't
another state object but an object that sets up Fishpod's initial properties in the level. Normally,
we would use the Create event of one of the state objects (probably obj_pod_standing ) to provide
any starting values (for things such as health and lives, for example). However, we are already
using the Create events to set up the behavior of each state. If we put starting values in these
Create events as well, then they would get reset between states (so you would go back to full
health while walking, for instance). This is clearly not desirable, so instead we will create a new
obj_pod object that sets up the initial properties for the character before changing itself into
obj_pod_standing . In fact, we don't want to give our character health at this stage, but we do need
to initialize the facing variable for the character. This will be done in the Create event of obj_pod ,
as it will only ever be created once at the very start of the level. It is essential that we initialize this
value somewhere; otherwise, Game Maker will quite rightly give an error the first time we try and
check what the value of facing is.

Creating a New Starting Object and Its Create Event
1.

Create a new object called obj_pod . You can set its Sprite to any one of the Fishpod sprites.

2. Click on the Add Event button and select the Create event.

Include a Set Variable action ( control tab). Type facing into Variable and FACE_LEFT
into Value . This sets the initial facing direction of Fishpod to the left.

3.

Include a Change Instance action ( main1 tab). Select obj_pod_standing from the
Change Into menu and yes for Perform Events . This will put the object into the
standing state and it will never return to the starting object again.

4.

■ Note If you are using the Lite version of Game Maker, then now is the time to “fake” the constant values
by including Set Variable actions ( control tab) at the very start of the Create event for obj_pod that to
create variables called FACE_LEFT with a value of 1 and FACE_RIGHT with a value of 2 . Unlike constants,
these variables will only be accessible in Fishpod objects, rather than globally (as constants are), but it
makes no difference to this example. You might wonder if we could have achieved the same thing simply
by setting the facing variable to the strings "FACE_LEFT" or "FACE_RIGHT" . However, while strings would
be just as readable for people, they are much harder and slower for machines to process, so the variable
or constant approach is much more advisable.

You can now reopen your test room and place an instance of obj_pod somewhere within the
level. Run the game and check that you can move Fishpod left and right using the arrow keys on
the keyboard. If you can't, then go back and check your steps carefully or compare your version
against our version in Chapter02/Games/fishpod2.gmk on the CD. Note that the character will
currently walk on thin air and through platforms as we've not handled those things yet. Pressing
the space bar will also cause Fishpod to spin endlessly and you'll have to quit the game (this is
because he is stuck in the jumping state and there is no way out of that state yet).