Krool’s Forces: Sweetening the Challenge - The Game Maker's Companion: Game Development - page 105

Reheated Resources
In order to save time (and paper), we have provided you with a new version of the game, which
contains all the new sprite and sound resources you'll need for this chapter. Although setting
these up is trivial, there are still a few things you should take note of, so we'll give you another
quick tour so that you don't miss anything crucial.

Exploring the Sprite Resources
• Use Game Maker to open zool7.gmk from the Chapter05/Games directory on the CD

and take a look at the sprite resources. The Zool group now contains left- and right-
facing sprites for three new actions (kick, spin, and die), as well as a missile sprite for
shooting. Open up some of the new sprites and click on the Modify Mask button.
Notice that the new action sprites have Precise Collision Checking turned off and
share the same bounding box and origin settings as the previous Zool sprites (in order
to ensure that the collision area doesn't change when switching sprites).

• Zool's missile sprite also has Precise Collision Checking turned off and has an

appropriately smaller bounding box set up. From now on, you can assume that we
have turned the Precise Collision Checking off and used Rectangular collision, unless
we specify otherwise. However, precise collision would actually work just as well in
this case, as Zool's missiles will get destroyed on contact with anything.

• The Platforms group now contains a new group called Lifts , which itself contains all

the sprites needed for moving platforms later on. It is not practical to use tiles for
moving objects, so these sprites are used for both the collision mask and the visual
image of lifts. Most of these have their Origins at X = 0 , Y = 0 , and use the Full image
option for the bounding box (which just means that the bounding box is the full size
of the sprite).

The new Hazards group contains all the hazards we will be adding in this chapter. First
comes a range of spikes in varying orientations. All of these use the Full image option for
the bounding box, which just means that the bounding box is the full size of the sprite.

•

• Next comes six different sprites for the Sweet Beastie enemy. These all have Manual

bounding boxes set up with identical boundaries ( Left = 8 , Right = 24 , Top = 4 ,
Bottom = 43 ). They also share the same Origin settings ( X = 16 , Y = 28 ), which are not at
the center of the sprite. This origin is offset in the y direction so that the base of the
bounding box rests on top of the platform's surface when the Beastie object is placed
in the room editor.

• The collision settings for the die sprites and the splat sprite (further down) are

irrelevant, as they are only included for visual effect and we will not handle their
collisions.

• The Beastie missile uses a Rectangular , Full image bounding box. It will be expected

to react to collisions and bounce across the landscape. In practice, you probably
wouldn't notice any difference using Precise Collision Checking in this case (as the
missile is such a simple, solid shape and is unlikely to get stuck), but we'll keep to the
principle that precise collision is the not the best choice for reactive collisions.

• The collision and origin settings for the Jelly enemy sprites are different from the

Sweet Beastie, but follow identical logic.

• The Bee enemy sprites are slightly different insofar as they do not need to rest neatly

on the surface of platforms, so their origins are in the center of the sprites.