Screens and Entities are two common FlatRedBall concepts. A Screen represents a container for game content and other Entities. Screens define the flow of your game. Often game developers create many screens up-front to help think through a game's structure. Here are some examples of Screens in a typical game:
GameS play Screen (like the playing Screen in Pong). This is usually called "GameScreen"
Splash Screen (like a FlatRedBall logo displaying splash Screen)
Main menu Screen
As you work with Screens you will find that they are very similar to Entities. To create a Screen:
Click on the Screens folder and select the Add Screen quick action...
...or right-click on the Screens folder and select Add Screen
Uncheck Add Map LayeredTileMap option - Beefball doesn't use Tiled maps
Accept the other defaults by clicking OK.
Notice that FlatRedBall suggests the name GameScreen for your screen. Recommended practice is to always have the screen where your game takes place called GameScreen. If your game has multiple levels, each level would inherit from GameScreen. Since Beefball does not have multiple levels, we only create GameScreen.
By default, your GameScreen now has a PlayerBallList - this is a list which will contain all PlayerBall instances in your GameScreen.
If you unchecked the Add Lists for Entities option, or if you would like to know how to create lists manually, follow these steps:
Select the PlayerBall entity
Click the Quick Actions tab
Click the Add PlayerBall List to GameScreen button
The PlayerBallList object will contain all of the PlayerBalls we plan on adding later. Our game is a two-player game, so it will eventually contain two PlayerBall instances. The PlayerBallList object will be used to define collision relationships in a later tutorial. Collision relationships define which objects can collide with each other (such as players vs the walls) and what to do when they collide (such as performing bounce physics).
Once you have at least one Screen in your game (GameScreen), you can add Entity instances to that Screen. Entities can be added through the editor or through game code. The editor provides a number of ways to add an entity:
Drag+drop an entity on a screen to add an instance...
... or add an instance to the GameScreen by selecting PlayerBall and clicking the Add PlayerBall Instance to GameScreen quick action. Note that this option will only exist if you have a Screen called GameScreen...
... or add an object to a screen by right-clicking on the GameScreen's Objects folder:
Right-click on your GameScreen's Objects folder
Select Add Object
Select Entity as the object type
Select PlayerBall as the type. The name will automatically be changed to PlayerBallInstance
Click OK
Now that you have a PlayerBall instance in your GameScreen, you can run the game to see it. You can run the game through either the FlatRedBall Editor or Visual Studio.
To run the game through the editor, click the Play button in the toobar at the top
To run the game through Visual Studio, click the Visual Studio icon to open the game in Visual Studio and run it like any other desktop project
Your game should now be open in Visual Studio.
Once the game runs, you should see a circle (the PlayerBall1 instance) in your Screen.
Now that we have an object in our screen we can take a moment to understand how the coordinates in FlatRedBall work. By default, our entity exists at X=0 and Y=0. We can observe this by selecting the PlayerBall1 instance and looking at its Variables tab.
By default the center of the screen is at the origin (0,0), and objects are positioned by their center, so the PlayerBall appears at the center of the screen.
For more information on how to control the screen's resolution and world units, see the FlatRedBall Resolution section.
For more information on how to control the Camera to change the center of the screen, see the Camera code reference.
To recap we now have an Entity called PlayerBall which has a Circle. We've also created a GameScreen which contains an instance of our PlayerBall. If we run our game, it shows a white circle (our PlayerBall instance).
We're now ready to start adding some code to our project. The next tutorial covers controlling your Entity's movement.
