Super Jumper: A 2D OpenGLES Game - Beginning Android Games - page 475

import com.badlogic.androidgames.framework.math.Vector2;
import com.badlogic.androidgames.jumper.World.WorldListener;
public class GameScreen extends GLScreen {
static final int GAME _ READY = 0;
static final int GAME _ RUNNING = 1;
static final int GAME _ PAUSED = 2;
static final int GAME _ LEVEL _ END = 3;
static final int GAME _ OVER = 4;
int state;
Camera2D guiCam;
Vector2 touchPoint;
SpriteBatcher batcher;
World world;
WorldListener worldListener;
WorldRenderer renderer;
Rectangle pauseBounds;
Rectangle resumeBounds;
Rectangle quitBounds;
int lastScore;
String scoreString;
The class starts off with constants defining the five states of the screen. Next, we have the
members. We have a camera for rendering the UI elements, as well as a vector so that we can
transform touch coordinates to world coordinates (as in the other screens, to a view frustum
of 320×480 units, our target resolution). Next, we have a SpriteBatcher , a World instance, and
a WorldListener . The WorldRenderer class is something we'll look into in a minute. It basically
just takes a World and renders it. Note that it also takes a reference to the SpriteBatcher as
a parameter of its constructor. This means that we'll use the same SpriteBatcher to render
the UI elements of the screen and to render the game world. The rest of the members are
Rectangles for different UI elements (such as the RESUME and QUIT menu entries on the
paused subscreen) and two members for keeping track of the current score. We want to avoid
creating a new string every frame when rendering the score so that we make the garbage
collector happy.
public GameScreen(Game game) {
super (game);
state = GAME _ READY ;
guiCam = new Camera2D(glGraphics, 320, 480);
touchPoint = new Vector2();
batcher = new SpriteBatcher(glGraphics, 1000);
worldListener = new WorldListener() {
public void jump() {
Assets. playSound (Assets. jumpSound );
}
public void highJump() {
Assets. playSound (Assets. highJumpSound );
}