Fighting Talk: The Empower Strikes Back - The Game Maker's Companion: Game Development - page 153

Note For the remainder of this chapter, we're going to take you step-by-step through the
implementation of the other user interface items: the timer, collection counter, health display, and lives
counter. However, they all follow a very similar structure, so feel free to spare your mouse finger and just
read the steps provided before loading zool15.gmk at the very end of the chapter.
Adding the Timer Object
1. Duplicate obj_score to create a new object called obj_time that uses spr_icon_time .
2. Add a Create event and include a Set Variable action ( control tab) that sets
time_allowed to 200 . We have just hard-coded the default number of seconds to
complete each level, but you could make this a global variable, or even a constant.
3. Include a Set Variable action that sets time_remaining to time_allowed .
4. Add a Step, Step event and include a Set Variable action that sets time_remaining to
time_allowed-(global.step_count/room_speed) . The room_speed variable stores the
number of steps in a second for this room (as set in the Room settings tab).
5. Include a Test Variable action that tests if time_remaining is smaller than 0 .
6. Follow this with a Restart Room action ( main1 tab).
7. Select the Draw event.
8. Edit the third Set Variable action for digit and replace 6 with 3 .
9. Edit the fourth Set Variable action for text_string and replace score with
time_remaining .
10. Edit the first Draw Sprite action for spr_icon_score and set it to draw spr_icon_time at
a Relative position of X = 230 , Y = 280 .
11. Edit the second Draw Sprite action for spr_icon_digits and change the position to
X = 240+(16*digit) , Y = 280 .
12. Reopen obj_controller and include a Create Instance action in its Create event that
creates an instance of obj_time .
Note that obj_time actually includes the actions restarting the level when time runs out, so if
you wanted to play the game without the time limit, then you can simply choose not to put
obj_time in the room.
Next, we consider the collectibles. These items are closely linked with completing each level,
as the exit does not appear until a certain percentage of them have been collected. Exits were
often placed in hard-to-reach positions, so once activated, the interface also provides a kind of
“compass” that points in the direction of the exit.