java - libGDX - 添加分数并将其显示在屏幕的左上角？

Question

这是 libGDX 中一个简单游戏的示例代码。当雨滴落入桶中时，分数应增加一分。总分应显示在左上角。

如果错过 3 滴，则显示 GAME OVER。我知道要增加分数，但我不知道要显示它。谢谢。

public class Drop implements ApplicationListener {
Texture dropImage;
Texture bucketImage;
Sound dropSound;
Music rainMusic;
SpriteBatch batch;
OrthographicCamera camera;
Rectangle bucket;
Array<Rectangle> raindrops;
long lastDropTime;

@Override
public void create() {
  // load the images for the droplet and the bucket, 64x64 pixels each
  dropImage = new Texture(Gdx.files.internal("droplet.png"));
  bucketImage = new Texture(Gdx.files.internal("bucket.png"));

  // load the drop sound effect and the rain background "music"
  dropSound = Gdx.audio.newSound(Gdx.files.internal("drop.wav"));
  rainMusic = Gdx.audio.newMusic(Gdx.files.internal("rain.mp3"));

  // start the playback of the background music immediately
  rainMusic.setLooping(true);
  rainMusic.play();

  // create the camera and the SpriteBatch
  camera = new OrthographicCamera();
  camera.setToOrtho(false, 800, 480);
  batch = new SpriteBatch();

  // create a Rectangle to logically represent the bucket
  bucket = new Rectangle();
  bucket.x = 800 / 2 - 64 / 2; // center the bucket horizontally
  bucket.y = 20; // bottom left corner of the bucket is 20 pixels above the bottom         screen edge
  bucket.width = 64;
  bucket.height = 64;

  // create the raindrops array and spawn the first raindrop
  raindrops = new Array<Rectangle>();
  spawnRaindrop();
}

private void spawnRaindrop() {
  Rectangle raindrop = new Rectangle();
  raindrop.x = MathUtils.random(0, 800-64);
  raindrop.y = 480;
  raindrop.width = 64;
  raindrop.height = 64;
  raindrops.add(raindrop);
  lastDropTime = TimeUtils.nanoTime();
}

@Override
public void render() {
  // clear the screen with a dark blue color. The
  // arguments to glClearColor are the red, green
  // blue and alpha component in the range [0,1]
  // of the color to be used to clear the screen.
  Gdx.gl.glClearColor(0, 0, 0.2f, 1);
  Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT);

  // tell the camera to update its matrices.
  camera.update();

  // tell the SpriteBatch to render in the
  // coordinate system specified by the camera.
  batch.setProjectionMatrix(camera.combined);

  // begin a new batch and draw the bucket and
  // all drops
  batch.begin();
  batch.draw(bucketImage, bucket.x, bucket.y);
  for(Rectangle raindrop: raindrops) {
     batch.draw(dropImage, raindrop.x, raindrop.y);
  }
  batch.end();

  // process user input
  if(Gdx.input.isTouched()) {
     Vector3 touchPos = new Vector3();
     touchPos.set(Gdx.input.getX(), Gdx.input.getY(), 0);
     camera.unproject(touchPos);
     bucket.x = touchPos.x - 64 / 2;
  }
  if(Gdx.input.isKeyPressed(Keys.LEFT)) bucket.x -= 200 * Gdx.graphics.getDeltaTime();
  if(Gdx.input.isKeyPressed(Keys.RIGHT)) bucket.x += 200 * Gdx.graphics.getDeltaTime();

  // make sure the bucket stays within the screen bounds
  if(bucket.x < 0) bucket.x = 0;
  if(bucket.x > 800 - 64) bucket.x = 800 - 64;

  // check if we need to create a new raindrop
  if(TimeUtils.nanoTime() - lastDropTime > 1000000000) spawnRaindrop();

  // move the raindrops, remove any that are beneath the bottom edge of
  // the screen or that hit the bucket. In the later case we play back
  // a sound effect as well.
  Iterator<Rectangle> iter = raindrops.iterator();
  while(iter.hasNext()) {
     Rectangle raindrop = iter.next();
     raindrop.y -= 200 * Gdx.graphics.getDeltaTime();
     if(raindrop.y + 64 < 0) iter.remove();
     if(raindrop.overlaps(bucket)) {
        dropSound.play();
        iter.remove();
     }
  }
}

@Override
public void dispose() {
  // dispose of all the native resources
  dropImage.dispose();
  bucketImage.dispose();
  dropSound.dispose();
  rainMusic.dispose();
  batch.dispose();
}

@Override
public void resize(int width, int height) {
}

@Override
public void pause() {
}

@Override
public void resume() {
}
}

Answer 1

Here是指向 libGDX 用户 wiki 的链接，当我遇到相同的 Pong 重制问题时，我发现它很有帮助。

要显示分数，您需要的工具是:一个用于保存分数的 int 变量，一个用于帮助显示分数的 String 或 CharacterSequence 变量(我将使用 String)，以及一个用于显示字体类型。

第一步:声明所有这些工具。

private int score;
private String yourScoreName;
BitmapFont yourBitmapFontName;

第二步:在create方法中初始化它们

public void create()     
    score = 0;
    yourScoreName = "score: 0";
    yourBitmapFontName = new BitmapFont();

第三步:递增 score 变量并更改碰撞逻辑方法中的 yourScoreName String 变量(当雨滴与水桶重叠时)。

if(raindrop.overlaps(bucket)) {
     score++;
     yourScoreName = "score: " + score;
     dropSound.play();
     iter.remove();

第四步:在 render() 方法中，设置字体的颜色并在 spriteBatch.begin 和 spriteBatch.end 之间调用 BitmapFont 上的 draw 方法。

batch.begin(); 
yourBitmapFontName.setColor(1.0f, 1.0f, 1.0f, 1.0f);
yourBitmapFontName.draw(batch, yourScoreName, 25, 100); 
batch.end();

使用:font.setColor() 方法中的参数，以便您可以看到它们与背景颜色的对比，font.draw() 方法中的数字参数，以获取顶部显示的分数相关纹理左上角(font.draw()方法中最后两个数字参数代表得分纹理的x和y坐标)。

第五步:运行它，然后微笑。

相同的逻辑将适用于显示“游戏结束”。出于启发式目的，我会将逻辑的创建留给您。

阅读 link 中的文档以更深入地了解魔法。