Platform Beginnings: An Idea with Legs - The Game Maker's Companion: Game Development - page 28

Creating the Remaining State Objects
1. Create a new object called obj_pod_walking . You can set its Sprite to be either
spr_pod_walk_left or spr_pod_walk_right , as we will be selecting the correct sprite
manually in the Create event. Set its Depth value to -1 so that it appears in front of
other objects.
2. Create a new object called obj_pod_jumping . Set its Sprite to be either
spr_pod_jump_left or spr_pod_jump_right and set its Depth to -1 .
3. Create a new object called obj_pod_falling . Set its Sprite to be either
spr_pod_fall_left or spr_pod_fall_right and set its Depth to -1 .
4. Create a new object called obj_pod_dying . Set its Sprite to be either spr_pod_jump_left
or spr_pod_jump_right and set its Depth to -1 . The jump sprite shows Fishpod
spinning, so we will also use this as a dying animation played as he falls from the
screen.
There are now two state transitions that we need to handle for obj_pod_standing (see Figure
2-9). The first is to change into the walking state when the player presses the arrow keys and the
second is to change into the jumping state when the player presses the space bar. This will
require three separate events in total: two Keyboard events for the left and right arrow keys and
one Key Press event for the space bar. These are implemented as follows.

Adding Key Events to the Standing State Object
1. Reopen the Object Properties for obj_pod_standing by double-clicking on it in the

resource list.

2. Click on the Add Event button and select the Keyboard <Left> event. We are using a

Keyboard event because we want Fishpod to keep walking when the player holds
down the arrow keys.

Include a Set Variable action ( control tab) in the actions list. Type facing into Variable
and FACE_LEFT into Value . We will use this to make sure that Fishpod faces left when
you press the left arrow key.

3.

4. Include a Change Instance action ( main1 tab) in the actions list. Select

obj_pod_walking from the Change Into menu and yes for Perform Events . This last
setting means that the Create event of obj_pod_walking will be called as part of the
change—the default is not to do so.

Repeat steps 2-4 using a Keyboard <Right> event and setting facing to FACE_RIGHT
instead.

5.

6.

Click on the Add Event button and select a Key Press <Space> event. We are using a
Key Press event here because we only want Fishpod to jump once for each press of the
space bar.

7. Include a Change Instance action ( main1 tab) in the actions list. Select
obj_pod_jumping from the Change Into menu and yes for Perform Events so that the
Create event of obj_pod_jumping is called as part of the change.
That completes all the behaviors and transitions for the standing state object. We'll work on
the walking state object next, as this will take us closer to something we can actually try out. As
before, the Create event for the walking state object will set up the behavior of Fishpod in that
state and a number of additional events that handle the transitions to other states.