我想添加一个blockbunny之类的背景，并且在android文件夹下的asset / images文件夹中有一个背景图片image。我试图将图像分为三个部分，并在Background类中将其添加为天空，云彩和山脉。由于某种原因，它抛出了空指针异常，因为在MyMainGame类中spritebatch为null。我已经在MyMainGame类的create方法中初始化了SpriteBatch。
这是我的MyMainGame.class
response.orderNumber == 0; // true
response.resultingOrders == null; // true
GameState是一个包含未实现方法的抽象类
public class OrderResponse
{
public long orderNumber;
public List<Order> resultingOrders;
[JsonConstructor]
public OrderResponse(long orderNumber, List<Order> resultingOrders)
{
this.orderNumber = orderNumber;
this.resultingOrders = resultingOrders;
}
}
public class Order
{
public long orderId
public decimal amount;
public string type;
[JsonConstructor]
public Order(long orderId, decimal amount, string type)
{
this.orderId = orderId;
this.amount = amount;
this.type; = type;
}
}
Play类扩展了GameState类
package com.mygdx.game;
import com.badlogic.gdx.ApplicationAdapter;
import com.badlogic.gdx.ApplicationListener;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.graphics.GL20;
import com.badlogic.gdx.graphics.GL30;
import com.badlogic.gdx.graphics.OrthographicCamera;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import com.mygdx.manager.Content;
import com.mygdx.manager.GameInputProcessor;
import com.mygdx.manager.GameStateManager;
import com.mygdx.manager.MyInput;
import javafx.scene.layout.Background;
import static com.mygdx.manager.Box2DVariables.PPM;
public class MyMainGame implements ApplicationListener {
SpriteBatch batch;
Texture img;
public static final int Width=320;
public static final int Height=240;
public static final int SCALE=2;
public static final float STEP= 1/60f; //60 frames per second
private float accumulator;
private SpriteBatch sb;
protected OrthographicCamera cam;
protected OrthographicCamera hud;
private Texture tex;
private Background[] backgrounds;
private GameStateManager gsm;
public SpriteBatch getSb() {
return sb;
}
public OrthographicCamera getCam() {
return cam;
}
public OrthographicCamera getHud() {
return hud;
}
public static Content con;
@Override
public void create () {
Gdx.input.setInputProcessor(new GameInputProcessor());
con=new Content();
con.loadTexture("images//sprite.jpg","sprite");
con.loadTexture("images//background.png","background");
gsm=new GameStateManager(this);
sb=new SpriteBatch();
cam=new OrthographicCamera(160,120);
cam.setToOrtho(false,Width/2,Height/2);
hud=new OrthographicCamera();
hud.setToOrtho(false,Width/2,Height/2);
}
@Override
public void render () {
cam.update();
hud.update();
accumulator +=Gdx.graphics.getDeltaTime();
while(accumulator>=STEP){
accumulator-=STEP;
gsm.update(STEP);
gsm.render();
MyInput.update();
}
}
public void resize(int width,int height){
sb.getProjectionMatrix().setToOrtho2D(0, 0, width, height);
}
public void dispose(){
con.disposeTexture("sprite");
con.disposeTexture("background");
}
public void pause(){
}
public void resume(){
gsm.setState(GameStateManager.PLAY);
}
}
我已将纹理加载到MyMainClass.java中，并将其存储在Content类的HashMap中 我将名为“ back”的背景图像获取为Texture，并在Play类的Play构造函数中将其分离为TextureRegions天空，云朵和山脉，并在Background类中传递它们。
package com.mygdx.gamestate;
import com.badlogic.gdx.graphics.OrthographicCamera;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import com.mygdx.game.MyMainGame;
import com.mygdx.manager.GameStateManager;
public abstract class GameState {
protected GameStateManager gsm;
protected MyMainGame game;
protected SpriteBatch sb;
protected OrthographicCamera cam;
protected OrthographicCamera hud;
protected GameState(GameStateManager gsm){
this.gsm=gsm;
game=gsm.game();
sb=game.getSb();
cam=game.getCam();
hud=game.getHud();
init();
}
public abstract void init();
public abstract void update(float dt);
public abstract void draw();
public abstract void render();
public abstract void handleInput();
public abstract void dispose();
}
背景类
public class Play extends GameState{
// private BitmapFont font=new BitmapFont();
private World world;
private Body playerBody;
private int viewportWidth= 10 * 32 ;
int viewportHeight= 8 * 32 ;
private Box2DDebugRenderer b2d;
private OrthographicCamera B2DCAM;
private TiledMap tileMap;
private OrthogonalTiledMapRenderer orthomap;
private MyContactListener cl;
private float tileSize;
private Background[] backgrounds;
private Texture back;
//file name
private final String LEVEL_1 ="maps/tilemap1.tmx";
public Play(GameStateManager gsm) {
super(gsm);
//setup box2d
world=new World(new Vector2(0,-9.8f),true);
cl=new MyContactListener();
world.setContactListener(cl);
sb=new SpriteBatch(1000);
//cam=new OrthographicCamera();
b2d=new Box2DDebugRenderer();
//create Player
createPlayer();
//create Tiles
createTiles();
orthomap = new OrthogonalTiledMapRenderer(tileMap,1/32f);
//setup Box2D Cam
B2DCAM=new OrthographicCamera();
B2DCAM.setToOrtho(false, MyMainGame.Width/PPM,MyMainGame.Height/PPM);
cam=new OrthographicCamera();
cam.setToOrtho(false,10,7);
back = MyMainGame.con.getTexture("background");
TextureRegion sky = new TextureRegion(back, 0, 0, 320, 240);
TextureRegion clouds = new TextureRegion(back, 0, 240, 320, 240);
TextureRegion mountains = new TextureRegion(back, 0, 480, 320, 240);
backgrounds = new Background[3];
backgrounds[0] = new Background(sky,cam, 0f);
backgrounds[1] = new Background(clouds, cam, 0.1f);
backgrounds[2] = new Background(mountains, cam, 0.2f);
/* //TODO - remove me
File file = new File(LEVEL_1);
if(file.exists())
System.out.println("file exists");*/
}
@Override
public void init() {
}
@Override
public void update(float dt) {
handleInput();
world.step(dt,6,2);
MyMainGame.con.getTexture("sprite");
for (Background b : backgrounds) {
b.update(dt);
}
}
@Override
public void draw() {
}
@Override
public void render() {
//clear screen
Gdx.gl20.glClear(GL20.GL_COLOR_BUFFER_BIT);
//
cam.position.set(playerBody.getPosition().x * PPM +MyMainGame.Width / 4,MyMainGame.Height / 2,0);
// cam.setToOrtho(false,playerBody.getPosition().x * PPM +MyMainGame.Width / 4,MyMainGame.Height / 2);
//cam.setPosition(playerBody.getPosition().x * PPM +MyMainGame.Width / 4, MyMainGame.Height / 2);
cam.setToOrtho(false,10,7);
cam.update();
sb.setProjectionMatrix(cam.combined);
for(int i = 0; i < backgrounds.length; i++) {
backgrounds[i].render(sb);
}
orthomap.setView(cam);
orthomap.render();
b2d.render(world,B2DCAM.combined);
}
@Override
public void handleInput() {
if(MyInput.isPressed((MyInput.SPACE))){
System.out.println("space pressed");
if(cl.isPlayerOnGround())
System.out.println(cl.isPlayerOnGround());
playerBody.applyForceToCenter(0,200,true);
}
}
@Override
public void dispose() {
world.dispose();
b2d.dispose();
tileMap.dispose();
orthomap.dispose();
}
private void createPlayer(){
BodyDef bodydef=new BodyDef();
FixtureDef fixdef=new FixtureDef();
PolygonShape shape=new PolygonShape();
//create player
bodydef.position.set(160/PPM,200/PPM);
bodydef.type= BodyDef.BodyType.DynamicBody;
playerBody=world.createBody(bodydef);
shape.setAsBox(5/PPM,5/PPM);
fixdef.shape=shape;
fixdef.filter.categoryBits= BIT_PLAYER;
fixdef.filter.maskBits=Box2DVariables.BIT_BLUE;
playerBody.createFixture(fixdef).setUserData("PLAYER");
//create foot sensor
shape.setAsBox(2/PPM,2/PPM,new Vector2(0,-5/PPM),0);
fixdef.shape=shape;
fixdef.filter.categoryBits= BIT_PLAYER;
fixdef.filter.maskBits=Box2DVariables.BIT_BLUE;
fixdef.isSensor=true;
playerBody.createFixture(fixdef).setUserData("FOOT");
}
private void createTiles(){
//load tile map
tileMap = new TmxMapLoader().load(LEVEL_1);
//orthomap = new OrthogonalTiledMapRenderer(tileMap,1);
tileSize=(int)tileMap.getProperties().get("tilewidth", Integer.class);
System.out.println("Tile Size " +tileSize);
TiledMapTileLayer layer;
layer=(TiledMapTileLayer)tileMap.getLayers().get("Blue");
createLayer(layer,Box2DVariables.BIT_BLUE);
layer=(TiledMapTileLayer)tileMap.getLayers().get("Green");
createLayer(layer,Box2DVariables.BIT_GREEN);
layer=(TiledMapTileLayer)tileMap.getLayers().get("Red");
createLayer(layer,Box2DVariables.BIT_RED);
System.out.println("Layer Height " +layer.getHeight());
System.out.println("Layer Width " +layer.getWidth());
}
private void createLayer(TiledMapTileLayer layer,short bits){
BodyDef bodydef=new BodyDef();
FixtureDef fixdef=new FixtureDef();
//go through cells in layer
for(int row=0;row<layer.getHeight();row++){
for(int col=0;col<layer.getWidth();col++){
//get cells
TiledMapTileLayer.Cell cell=layer.getCell(col,row);
//check if cell exists
if(cell==null) continue;
if(cell.getTile()==null) continue;
//create body and fixture from cell
bodydef.type= BodyDef.BodyType.StaticBody;
bodydef.position.set((col+0.5f)*tileSize/PPM,(row+0.5f)*tileSize/PPM);
ChainShape cs=new ChainShape();
Vector2[] v=new Vector2[3];
//bottom left
v[0]=new Vector2(-tileSize/2/PPM,-tileSize/2/PPM);
//top left
v[1]=new Vector2(-tileSize/2/PPM,tileSize/2/PPM);
//top right corner
v[2]=new Vector2(tileSize/2/PPM,tileSize/2/PPM);
cs.createChain(v);
fixdef.friction=0;
fixdef.shape =cs;
fixdef.filter.categoryBits=Box2DVariables.BIT_BLUE;
fixdef.filter.maskBits=BIT_PLAYER;
fixdef.isSensor=false;
world.createBody(bodydef).createFixture(fixdef);
}
}
}
}
我在渲染方法的Play类中收到一个错误，作为空指针异常。真的不知道发生了什么！ sb.setProjectionMatrix提供nullpointer异常！
TextureRegion sky = new TextureRegion(back, 0, 0, 320, 240);
TextureRegion clouds = new TextureRegion(back, 0, 240, 320, 240);
TextureRegion mountains = new TextureRegion(back, 0, 480, 320, 240);
backgrounds = new Background[3];
backgrounds[0] = new Background(sky,cam, 0f);
backgrounds[1] = new Background(clouds, cam, 0.1f);
backgrounds[2] = new Background(mountains, cam, 0.2f);
如何分割背景图像并按照上面在游戏中所示添加它？