Designing Games with Game Maker - YoYo Games

and the object can take an appropriate action, like moving in the direction indicated. We hope
you get the idea. For each object you design, you can indicate actions for various events; in
this way defining the behavior of the object.
Once you have defined your objects it is time to define the rooms in which they will live.
Rooms can be used for levels in your game or to check out different places. There are actions
to move from one room to another. Rooms, first of all, have a background. This can be a
simple color or an image. Such background images can be created in Game Maker or you can
load them from files. (The background can do a lot of things but for the time being, just
consider it as something that makes the rooms look nice.) Next, you can place the objects in
the room. You can place multiple instances of the same object in a room. So, for example, you
need to define just one wall object and can use it at many places. Also you can have multiple
instances of the same monster objects, as long as they have the same behavior.
Now you are ready to run the game. The first room will be shown and objects will come to life
because of the actions in their creation events. They will start reacting to each other due to
actions in collision events and they can react to the player using the actions in keyboard or
mouse events.
So in summary, the following things (often called resources) play a crucial role:
• objects: which are the true entities in the game
• rooms: the places (levels) in which the objects live
• sprites: (animated) images that are used to represent the objects
• sounds: these can be used in games, either as background music or as effects
• backgrounds: the images used as background for the rooms
There are actually a number of other types of resources: paths, scripts, fonts, and time lines.
These are important for more complicated games. You will only see them when you run Game
Maker in advanced mode. They will be treated in the advanced chapters later in this
document.
Let us look at an example
It is good first to have a look at how to make a very simple example. We assume here that
you run Game Maker in simple mode. The first step is to describe the game we want to make.
(You should always do this first; it will save you a lot of work later.) The game will be very