Table of contents
Play Level Screen
The play level screen handles the logic and graphics related to playing the actual game (walking around the map, interacting with things, etc.). It is loaded when the “PLAY GAME” option is selected from the game’s main menu.
The class file for it is PlayLevelScreen.java which can be found in the Screens package.
Functionality
This is the screen where the actual game is played. The map and player are loaded and the game carries out from there until the level is beaten. Despite the PlayLevelScreen class having to seemingly do so much, a vast majority of the game code is abstracted away into the Player and Map classes which keeps the screen’s code pretty minimal.
The PlayLevelScreenState enum defined in the class is used to determine what the PlayLevelScreen should be doing at a specific point in time – its “current state” is stored in the playLevelScreenState instance variable. There are two different states that the PlayLevelScreen can be in:
- RUNNING – game is currently running (map is loaded, player can move around, etc.)
- LEVEL_COMPLETED – the level has been completed, which happens when the player finishes the game’s story (the cat’s missing ball is found)
Running State
The RUNNING state is the default state that the PlayLevelScreen is set to when it first loads.
As mentioned earlier, while this state does have the most going on considering it’s the actual game itself being run, nearly all of the game code is abstracted away to the Map and Player classes. This is the only thing PlayLevelScreen has to do for this state during its update and draw cycles:
update method:
player.update();
map.update(player);
and
draw method:
map.draw(player, graphicsHandler);
Basically, the Map and Player classes are updated and drawn each cycle, and they handle the rest of the work. The specific Map and Player class instance used for the level is defined in the screen’s initialize method. Currently, this game currently only has one playable map (TestMap.java file in the Map package) and one player type (Cat.java file in the Players package). From there, the PlayLevelScreen just continually calls their update and draw methods to carry out the game. The documentation for the Map class is located here, and for the Player class is located here.
When in this state, the game can be played!
Level Completed State
When the player finishes the game’s story (finds the cat’s missing ball), the level is “completed” and the PlayLevelScreen's state is changed to LEVEL_COMPLETED. When in this state, the “Win” screen is loaded, which is a separate Screen class (WinScreen.java).
The “Win” screen’s only job is to paint the entire screen black and show the “You Win!” text along with instructions to tell the player what they can do from this screen. The PlayLevelScreen sets up and loads the WinScreen from within itself, rather than making a separate entry in the ScreenCoordinator class. This structure is important in order to not bloat the ScreenCoordinator class, as the ScreenCoordinator class should really only be used for the “core” screens of the game. While it may seem like overkill to have created an entire separate screen class for WinScreen for such a tiny amount of functionality, it keeps the game code organized. If in the future the graphics for the win screen were to get more complex and involved, keeping the screens separate prevents bloating of the PlayLevelScreen class.
From the WinScreen, the player can press the space key to restart the level, or press the escape key to go back to the main menu. The WinScreen class handles detecting those key inputs and sets ScreenCoordinator's game state accordingly based on what key the user presses:
// if space is pressed, reset level. if escape is pressed, go back to main menu
if (Keyboard.isKeyDown(Key.SPACE) && !keyLocker.isKeyLocked(Key.SPACE)) {
playLevelScreen.resetLevel();
} else if (Keyboard.isKeyDown(Key.ESC) && !keyLocker.isKeyLocked(Key.ESC)) {
playLevelScreen.goBackToMenu();
}
The WinScreen class is passed the PlayLevelScreen instance to allow for calling its instance methods. The PlayLevelScreen class exposes methods for resetLevel and goBackToMenu to allow the WinScreen to tell it what to do.